This reverts r366419 because the analysis performed is within the context of
the loop and it's only valid to add wrapping flags to "global" expressions if
they're always correct.
llvm-svn: 373184
exits"
Get a better approach in https://reviews.llvm.org/D68107 to solve the problem.
Revert the initial patch and will commit the new one soon.
This reverts commit rL372990.
llvm-svn: 373044
Summary: As discussed in the loop group meeting. With the current
definition of loop guard, we should not allow multiple loop exiting
blocks. For loops that has multiple loop exiting blocks, we can simply
unable to find the loop guard.
When getUniqueExitBlock() obtains a vector size not equals to one, that
means there is either no exit blocks or there exists more than one
unique block the loop exit to.
If we don't disallow loop with multiple loop exit blocks, then with our
current implementation, there can exist exit blocks don't post dominated
by the non pre-header successor of the guard block.
Reviewer: reames, Meinersbur, kbarton, etiotto, bmahjour
Reviewed By: Meinersbur, kbarton
Subscribers: fhahn, hiraditya, llvm-commits
Tag: LLVM
Differential Revision: https://reviews.llvm.org/D66529
llvm-svn: 373011
The static analyzer is warning about a potential null dereference, but we should be able to use cast<ExtractValueInst> directly and if not assert will fire for us.
llvm-svn: 372993
for extreme large case.
We had a case that a single loop which has 4000 exits and the average number
of predecessors of each exit is > 1000, and we found compiling the case spent
a significant amount of time on checking whether a loop has dedicated exits.
This patch adds a limit for the iterations to the check. With the patch, the
time to compile our testcase reduced from 1000s to 200s (clang release build).
Differential Revision: https://reviews.llvm.org/D67359
llvm-svn: 372990
The static analyzer is warning about a potential null dereferences, but since the pointer is only used in a switch statement for Operator::getOpcode() (with an empty default) then its easiest just to wrap this in a null test as the dyn_cast might return null here.
llvm-svn: 372962
Previously we might attempt to use a BitCast to turn bits into vectors of pointers,
but that requires an inttoptr cast to be legal. Add an assertion to detect the formation of illegal bitcast attempts
early (in the tests, we often constant-fold away the result before getting to this assertion check),
while being careful to still handle the early-return conditions without adding extra complexity in the result.
Patch by Jameson Nash <jameson@juliacomputing.com>.
Differential Revision: https://reviews.llvm.org/D65057
llvm-svn: 372940
Summary:
If a block has all incoming values with the same MemoryAccess (ignoring
incoming values from unreachable blocks), then use that incoming
MemoryAccess and do not create a Phi in the first place.
Revert IDF work-around added in rL372673; it should not be required unless
the Def inserted is the first in its block.
The patch also cleans up a series of tests, added during the many
iterations on insertDef.
The patch also fixes PR43438.
The same issue that occurs in insertDef with "adding phis, hence the IDF of
Phis is needed", can also occur in fixupDefs: the `getPreviousRecursive`
call only adds Phis walking on the predecessor edges, which means there
may be the case of a Phi added walking the CFG "backwards" which
triggers the needs for an additional Phi in successor blocks.
Such Phis are added during fixupDefs only in the presence of unreachable
blocks.
Hence this highlights the need to avoid adding Phis in blocks with
unreachable predecessors in the first place.
Reviewers: george.burgess.iv
Subscribers: Prazek, sanjoy.google, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D67995
llvm-svn: 372932
Because we do not constant fold multiplications in SimplifyFMAMul,
we match 1.0 and 0.0 for both operands, as multiplying by them
is guaranteed to produce an exact result (if it is allowed to do so).
Note that it is not enough to just swap the operands to ensure a
constant is on the RHS, as we want to also cover the case with
2 constants.
Reviewers: lebedev.ri, spatel, reames, scanon
Reviewed By: lebedev.ri, reames
Differential Revision: https://reviews.llvm.org/D67553
llvm-svn: 372915
As @reames pointed out post-commit, rL371518 adds additional rounding
in some cases, when doing constant folding of the multiplication.
This breaks a guarantee llvm.fma makes and must be avoided.
This patch reapplies rL371518, but splits off the simplifications not
requiring rounding from SimplifFMulInst as SimplifyFMAFMul.
Reviewers: spatel, lebedev.ri, reames, scanon
Reviewed By: reames
Differential Revision: https://reviews.llvm.org/D67434
llvm-svn: 372899
Currently m_Br only takes references to BasicBlock*, which limits its
flexibility. For example, you have to declare a variable, even if you
ignore the result or you have to have additional checks to make sure the
matched BB matches an expected one.
This patch adds m_BasicBlock and m_SpecificBB matchers, which can be
used like the existing matchers for constants or values.
I also had a look at the existing uses and updated a few. IMO it makes
the code a bit more explicit.
Reviewers: spatel, craig.topper, RKSimon, majnemer, lebedev.ri
Reviewed By: lebedev.ri
Differential Revision: https://reviews.llvm.org/D68013
llvm-svn: 372885
The changes here are based on the corresponding diffs for allowing FMF on 'select':
D61917 <https://reviews.llvm.org/D61917>
As discussed there, we want to have fast-math-flags be a property of an FP value
because the alternative (having them on things like fcmp) leads to logical
inconsistency such as:
https://bugs.llvm.org/show_bug.cgi?id=38086
The earlier patch for select made almost no practical difference because most
unoptimized conditional code begins life as a phi (based on what I see in clang).
Similarly, I don't expect this patch to do much on its own either because
SimplifyCFG promptly drops the flags when converting to select on a minimal
example like:
https://bugs.llvm.org/show_bug.cgi?id=39535
But once we have this plumbing in place, we should be able to wire up the FMF
propagation and start solving cases like that.
The change to RecurrenceDescriptor::AddReductionVar() is required to prevent a
regression in a LoopVectorize test. We are intersecting the FMF of any
FPMathOperator there, so if a phi is not properly annotated, new math
instructions may not be either. Once we fix the propagation in SimplifyCFG, it
may be safe to remove that hack.
Differential Revision: https://reviews.llvm.org/D67564
llvm-svn: 372878
The changes here are based on the corresponding diffs for allowing FMF on 'select':
D61917
As discussed there, we want to have fast-math-flags be a property of an FP value
because the alternative (having them on things like fcmp) leads to logical
inconsistency such as:
https://bugs.llvm.org/show_bug.cgi?id=38086
The earlier patch for select made almost no practical difference because most
unoptimized conditional code begins life as a phi (based on what I see in clang).
Similarly, I don't expect this patch to do much on its own either because
SimplifyCFG promptly drops the flags when converting to select on a minimal
example like:
https://bugs.llvm.org/show_bug.cgi?id=39535
But once we have this plumbing in place, we should be able to wire up the FMF
propagation and start solving cases like that.
The change to RecurrenceDescriptor::AddReductionVar() is required to prevent a
regression in a LoopVectorize test. We are intersecting the FMF of any
FPMathOperator there, so if a phi is not properly annotated, new math
instructions may not be either. Once we fix the propagation in SimplifyCFG, it
may be safe to remove that hack.
Differential Revision: https://reviews.llvm.org/D67564
llvm-svn: 372866
Summary:
MemoryPhis may be needed following a Def insertion inthe IDF of all the
new accesses added (phis + potentially a def). Ensure this also occurs when
only the new MemoryPhis are the defining accesses.
Note: The need for computing IDF here is because of new Phis added with
edges incoming from unreachable code, Phis that had previously been
simplified. The preferred solution is to not reintroduce such Phis.
This patch is the needed fix while working on the preferred solution.
Reviewers: george.burgess.iv
Subscribers: Prazek, sanjoy.google, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D67927
llvm-svn: 372673
Static analyzer complains about const_cast uninitialized variables, we should explicitly set these to null.
Ideally that const wrapper would go away though.......
llvm-svn: 372603
Summary:
The CallAnalyzer::visitSwitchInst has an early exit when the estimated
lower bound of the switch cost will put the overall cost of the inline
above the threshold. However, this code is not correctly estimating the
lower bound for switches that can be transformed into bit tests, leading
to unnecessary lost inlines, and also differing behavior with
optimization remarks enabled.
First, the early exit is controlled by whether ComputeFullInlineCost is
enabled or not, and that in turn is disabled by default but enabled when
enabling -pass-remarks=missed. This by itself wouldn't lead to a
problem, except that as described below, the lower bound can be above
the real lower bound, so we can sometimes get different inline decisions
with inline remarks enabled, which is problematic.
The early exit was added in along with a new switch cost model in D31085.
The reason why this early exit was added is due to a concern one reviewer
raised about compile time for large switches:
https://reviews.llvm.org/D31085?id=94559#inline-276200
However, the code just below there calls
getEstimatedNumberOfCaseClusters, which in turn immediately calls
BasicTTIImpl getEstimatedNumberOfCaseClusters, which in the worst case
does a linear scan of the cases to get the high and low values. The
bit test handling in particular is guarded by whether the number of
cases fits into the max bit width. There is no suggestion that anyone
measured a compile time issue, it appears to be theoretical.
The problem is that the reviewer's comment about the lower bound
calculation is incorrect, specifically in the case of a switch that can
be lowered to a bit test. This isn't followed up on the comment
thread, but the author does add a FIXME to that effect above the early
exit added when they subsequently revised the patch.
As a result, we were incorrectly early exiting and not inlining
functions with switch statements that would be lowered to bit tests in
cases where we were nearing the threshold. Combined with the fact that
this early exit was skipped with opt remarks enabled, this caused
different inlining decisions to be made when -pass-remarks=missed is
enabled to debug the missing inline.
Remove the early exit for the above reasons.
I also copied over an existing AArch64 inlining test to X86, and
adjusted the threshold so that the bit test inline only occurs with the
fix in this patch.
Reviewers: davidxl
Subscribers: eraman, kristof.beyls, haicheng, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D67716
llvm-svn: 372440
At present, `-scalar-evolution-max-iterations` is a `cl::Optional`
option, which means it demands to be passed exactly zero or one times.
Our build system makes it pretty tricky to guarantee this. We often
accidentally pass the flag more than once (but always with the same
value) which results in an error, after which compilation fails:
```
clang (LLVM option parsing): for the -scalar-evolution-max-iterations option: may only occur zero or one times!
```
It seems reasonable to allow -scalar-evolution-max-iterations to be
passed more than once. Quoting the [[ http://llvm.org/docs/CommandLine.html#controlling-the-number-of-occurrences-required-and-allowed | documentation ]]:
> The cl::ZeroOrMore modifier ... indicates that your program will allow the option to be specified zero or more times.
> ...
> If an option is specified multiple times for an option of the cl::opt class, only the last value will be retained.
Original patch by: Enrico Bern Hardy Tanuwidjaja <etanuwid@fb.com>
Differential Revision: https://reviews.llvm.org/D67512
llvm-svn: 372346
This patch implements the demangling functionality as described in the
Vector Function ABI. This patch will be used to implement the
SearchVectorFunctionSystem (SVFS) as described in the RFC:
http://lists.llvm.org/pipermail/llvm-dev/2019-June/133484.html
A fuzzer is added to test the demangling utility.
Patch by Sumedh Arani <sumedh.arani@arm.com>
Differential revision: https://reviews.llvm.org/D66024
llvm-svn: 372343
Summary:
This is the first patch in a series of patches that will implement data dependence graph in LLVM. Many of the ideas used in this implementation are based on the following paper:
D. J. Kuck, R. H. Kuhn, D. A. Padua, B. Leasure, and M. Wolfe (1981). DEPENDENCE GRAPHS AND COMPILER OPTIMIZATIONS.
This patch contains support for a basic DDGs containing only atomic nodes (one node for each instruction). The edges are two fold: def-use edges and memory-dependence edges.
The implementation takes a list of basic-blocks and only considers dependencies among instructions in those basic blocks. Any dependencies coming into or going out of instructions that do not belong to those basic blocks are ignored.
The algorithm for building the graph involves the following steps in order:
1. For each instruction in the range of basic blocks to consider, create an atomic node in the resulting graph.
2. For each node in the graph establish def-use edges to/from other nodes in the graph.
3. For each pair of nodes containing memory instruction(s) create memory edges between them. This part of the algorithm goes through the instructions in lexicographical order and creates edges in reverse order if the sink of the dependence occurs before the source of it.
Authored By: bmahjour
Reviewer: Meinersbur, fhahn, myhsu, xtian, dmgreen, kbarton, jdoerfert
Reviewed By: Meinersbur, fhahn, myhsu
Subscribers: ychen, arphaman, simoll, a.elovikov, mgorny, hiraditya, jfb, wuzish, llvm-commits, jsji, Whitney, etiotto
Tag: #llvm
Differential Revision: https://reviews.llvm.org/D65350
llvm-svn: 372238
Summary:
This fixes B42473 and B42706.
This patch makes the SDA propagate branch divergence until the end of the RPO traversal. Before, the SyncDependenceAnalysis propagated divergence only until the IPD in rpo order. RPO is incompatible with post dominance in the presence of loops. This made the SDA crash because blocks were missed in the propagation.
Reviewers: foad, nhaehnle
Reviewed By: foad
Subscribers: jvesely, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D65274
llvm-svn: 372223
Summary:
This is the first patch in a series of patches that will implement data dependence graph in LLVM. Many of the ideas used in this implementation are based on the following paper:
D. J. Kuck, R. H. Kuhn, D. A. Padua, B. Leasure, and M. Wolfe (1981). DEPENDENCE GRAPHS AND COMPILER OPTIMIZATIONS.
This patch contains support for a basic DDGs containing only atomic nodes (one node for each instruction). The edges are two fold: def-use edges and memory-dependence edges.
The implementation takes a list of basic-blocks and only considers dependencies among instructions in those basic blocks. Any dependencies coming into or going out of instructions that do not belong to those basic blocks are ignored.
The algorithm for building the graph involves the following steps in order:
1. For each instruction in the range of basic blocks to consider, create an atomic node in the resulting graph.
2. For each node in the graph establish def-use edges to/from other nodes in the graph.
3. For each pair of nodes containing memory instruction(s) create memory edges between them. This part of the algorithm goes through the instructions in lexicographical order and creates edges in reverse order if the sink of the dependence occurs before the source of it.
Authored By: bmahjour
Reviewer: Meinersbur, fhahn, myhsu, xtian, dmgreen, kbarton, jdoerfert
Reviewed By: Meinersbur, fhahn, myhsu
Subscribers: ychen, arphaman, simoll, a.elovikov, mgorny, hiraditya, jfb, wuzish, llvm-commits, jsji, Whitney, etiotto
Tag: #llvm
Differential Revision: https://reviews.llvm.org/D65350
llvm-svn: 372162
Summary:
When inserting a Def, the current algorithm is walking edges backward
and inserting new Phis where needed. There may be additional Phis needed
in the IDF of the newly inserted Def and Phis.
Adding Phis in the IDF of the Def was added ina previous patch, but we
may also need other Phis in the IDF of the newly added Phis.
Reviewers: george.burgess.iv
Subscribers: Prazek, sanjoy.google, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D67637
llvm-svn: 372138
Summary:
Regularly when moving an instruction that may not read or write memory,
the instruction is not modelled in MSSA, so not action is necessary.
For a non-conventional AA pipeline, MSSA needs to explicitly check when
creating accesses, so as to not model instructions that may not read and
write memory.
Reviewers: george.burgess.iv
Subscribers: Prazek, sanjoy.google, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D67562
llvm-svn: 372137
We were failing to compute trip counts (both exact and maximum) for any loop which involved a comparison against either an umin or smin. It looks like this simply got missed when we added smin/umin to SCEV. (Note: umin was submitted separately earlier today. Turned out two folks hit this at the same time.)
Differential Revision: https://reviews.llvm.org/D67514
llvm-svn: 371776
Expanding the folding of `nearbyint()`, `rint()` and `trunc()` to library
functions, in addition to the current support for intrinsics.
Differential revision: https://reviews.llvm.org/D67468
llvm-svn: 371774
This patch adds support for SCEVUMinExpr to getRangeRef,
similar to the support for SCEVUMaxExpr.
Reviewers: sanjoy.google, efriedma, reames, nikic
Reviewed By: sanjoy.google
Differential Revision: https://reviews.llvm.org/D67177
llvm-svn: 371768
Implement a TODO from rL371452, and handle loop invariant addresses in predicated blocks. If we can prove that the load is safe to speculate into the header, then we can avoid using a masked.load in favour of a normal load.
This is mostly about vectorization robustness. In the common case, it's generally expected that LICM/LoadStorePromotion would have eliminated such loads entirely.
Differential Revision: https://reviews.llvm.org/D67372
llvm-svn: 371745
Folding for fma/fmuladd was added here:
rL202914
...and as seen in existing/unchanged tests, that works to propagate NaN
if it's already an input, but we should fold an fma() that creates NaN too.
From IEEE-754-2008 7.2 "Invalid Operation", there are 2 clauses that apply
to fma, so I added tests for those patterns:
c) fusedMultiplyAdd: fusedMultiplyAdd(0, ∞, c) or fusedMultiplyAdd(∞, 0, c)
unless c is a quiet NaN; if c is a quiet NaN then it is implementation
defined whether the invalid operation exception is signaled
d) addition or subtraction or fusedMultiplyAdd: magnitude subtraction of
infinities, such as: addition(+∞, −∞)
Differential Revision: https://reviews.llvm.org/D67446
llvm-svn: 371735
Summary:
I don't have a direct motivational case for this,
but it would be good to have this for completeness/symmetry.
This pattern is basically the motivational pattern from
https://bugs.llvm.org/show_bug.cgi?id=43251
but with different predicate that requires that the offset is non-zero.
The completeness bit comes from the fact that a similar pattern (offset != zero)
will be needed for https://bugs.llvm.org/show_bug.cgi?id=43259,
so it'd seem to be good to not overlook very similar patterns..
Proofs: https://rise4fun.com/Alive/21b
Also, there is something odd with `isKnownNonZero()`, if the non-zero
knowledge was specified as an assumption, it didn't pick it up (PR43267)
Reviewers: spatel, nikic, xbolva00
Reviewed By: spatel
Subscribers: hiraditya, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D67411
llvm-svn: 371718
When possible, replace calls to library routines on the host with equivalent
ones in LLVM.
Differential revision: https://reviews.llvm.org/D67459
llvm-svn: 371677
This was actually the original intention in D67332,
but i messed up and forgot about it.
This patch was originally part of D67411, but precommitting this.
llvm-svn: 371630
Configure TLI to say that r600/amdgpu does not have any library
functions, such that InstCombine does not do anything like turn sin/cos
into the library function @tan with sufficient fast math flags.
Differential Revision: https://reviews.llvm.org/D67406
Change-Id: I02f907d3e64832117ea9800e9f9285282856e5df
llvm-svn: 371592
Summary:
Do not model debuginfo intrinsics in MemorySSA.
Regularly these are non-memory modifying instructions. With -disable-basicaa, they were being modelled as Defs.
Reviewers: george.burgess.iv
Subscribers: aprantl, Prazek, sanjoy.google, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D67307
llvm-svn: 371565
Expose a utility function so that all places which want to suppress speculation (when otherwise legal) due to ordering and/or sanitizer interaction can do so.
llvm-svn: 371556
Since NaN is very rare in normal programs, so the probability for floating point unordered comparison should be extremely small. Current probability is 3/8, it is too large, this patch changes it to a tiny number.
Differential Revision: https://reviews.llvm.org/D65303
llvm-svn: 371541
Summary:
This is motivated by D67122 sanitizer check enhancement.
That patch seemingly worsens `-fsanitize=pointer-overflow`
overhead from 25% to 50%, which strongly implies missing folds.
In this particular case, given
```
char* test(char& base, unsigned long offset) {
return &base + offset;
}
```
it will end up producing something like
https://godbolt.org/z/LK5-iH
which after optimizations reduces down to roughly
```
define i1 @t0(i8* nonnull %base, i64 %offset) {
%base_int = ptrtoint i8* %base to i64
%adjusted = add i64 %base_int, %offset
%non_null_after_adjustment = icmp ne i64 %adjusted, 0
%no_overflow_during_adjustment = icmp uge i64 %adjusted, %base_int
%res = and i1 %non_null_after_adjustment, %no_overflow_during_adjustment
ret i1 %res
}
```
Without D67122 there was no `%non_null_after_adjustment`,
and in this particular case we can get rid of the overhead:
Here we add some offset to a non-null pointer,
and check that the result does not overflow and is not a null pointer.
But since the base pointer is already non-null, and we check for overflow,
that overflow check will already catch the null pointer,
so the separate null check is redundant and can be dropped.
Alive proofs:
https://rise4fun.com/Alive/WRzq
There are more patterns of "unsigned-add-with-overflow", they are not handled here,
but this is the main pattern, that we currently consider canonical,
so it makes sense to handle it.
https://bugs.llvm.org/show_bug.cgi?id=43246
Reviewers: spatel, nikic, vsk
Reviewed By: spatel
Subscribers: hiraditya, llvm-commits, reames
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D67332
llvm-svn: 371349
Summary:
Add an intrinsic that takes 2 unsigned integers with
the scale of them provided as the third argument and
performs fixed point multiplication on them. The
result is saturated and clamped between the largest and
smallest representable values of the first 2 operands.
This is a part of implementing fixed point arithmetic
in clang where some of the more complex operations
will be implemented as intrinsics.
Patch by: leonardchan, bjope
Reviewers: RKSimon, craig.topper, bevinh, leonardchan, lebedev.ri, spatel
Reviewed By: leonardchan
Subscribers: ychen, wuzish, nemanjai, MaskRay, jsji, jdoerfert, Ka-Ka, hiraditya, rjmccall, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D57836
llvm-svn: 371308
This addresses the issue mentioned on D19867. When we simplify
with.overflow instructions in CVP, we leave behind extractvalue
of insertvalue sequences that LVI no longer understands. This
means that we can not simplify any instructions based on the
with.overflow anymore (until some over pass like InstCombine
cleans them up).
This patch extends LVI extractvalue handling by calling
SimplifyExtractValueInst (which doesn't do anything more than
constant folding + looking through insertvalue) and using the block
value of the simplification.
A possible alternative would be to do something similar to
SimplifyIndVars, where we instead directly try to replace
extractvalue users of the with.overflow. This would need some
additional structural changes to CVP, as it's currently not legal
to remove anything but the current instruction -- we'd have to
introduce a worklist with instructions scheduled for deletion or similar.
Differential Revision: https://reviews.llvm.org/D67035
llvm-svn: 371306
Summary:
This is the first change to enable the TLI to be built per-function so
that -fno-builtin* handling can be migrated to use function attributes.
See discussion on D61634 for background. This is an enabler for fixing
handling of these options for LTO, for example.
This change should not affect behavior, as the provided function is not
yet used to build a specifically per-function TLI, but rather enables
that migration.
Most of the changes were very mechanical, e.g. passing a Function to the
legacy analysis pass's getTLI interface, or in Module level cases,
adding a callback. This is similar to the way the per-function TTI
analysis works.
There was one place where we were looking for builtins but not in the
context of a specific function. See FindCXAAtExit in
lib/Transforms/IPO/GlobalOpt.cpp. I'm somewhat concerned my workaround
could provide the wrong behavior in some corner cases. Suggestions
welcome.
Reviewers: chandlerc, hfinkel
Subscribers: arsenm, dschuff, jvesely, nhaehnle, mehdi_amini, javed.absar, sbc100, jgravelle-google, eraman, aheejin, steven_wu, george.burgess.iv, dexonsmith, jfb, asbirlea, gchatelet, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D66428
llvm-svn: 371284
Summary:
I'm not planning to check this in at the moment, but feedback is very welcome, in particular how this affects performance.
The feedback obtains here will guide the next steps towards enabling this.
This patch enables the use of MemorySSA in the loop pass manager.
Passes that currently use MemorySSA:
- EarlyCSE
Passes that use MemorySSA after this patch:
- EarlyCSE
- LICM
- SimpleLoopUnswitch
Loop passes that update MemorySSA (and do not use it yet, but could use it after this patch):
- LoopInstSimplify
- LoopSimplifyCFG
- LoopUnswitch
- LoopRotate
- LoopSimplify
- LCSSA
Loop passes that do *not* update MemorySSA:
- IndVarSimplify
- LoopDelete
- LoopIdiom
- LoopSink
- LoopUnroll
- LoopInterchange
- LoopUnrollAndJam
- LoopVectorize
- LoopReroll
- IRCE
Reviewers: chandlerc, george.burgess.iv, davide, sanjoy, gberry
Subscribers: jlebar, Prazek, dmgreen, jdoerfert, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D58311
llvm-svn: 370384
Summary:
Now that with D65143/D65144 we've produce `@llvm.umul.with.overflow`,
and with D65147 we've flattened the CFG, we now can see that
the guard may have been there to prevent division by zero is redundant.
We can simply drop it:
```
----------------------------------------
Name: no overflow or zero
%iszero = icmp eq i4 %y, 0
%umul = smul_overflow i4 %x, %y
%umul.ov = extractvalue {i4, i1} %umul, 1
%umul.ov.not = xor %umul.ov, -1
%retval.0 = or i1 %iszero, %umul.ov.not
ret i1 %retval.0
=>
%iszero = icmp eq i4 %y, 0
%umul = smul_overflow i4 %x, %y
%umul.ov = extractvalue {i4, i1} %umul, 1
%umul.ov.not = xor %umul.ov, -1
%retval.0 = or i1 %iszero, %umul.ov.not
ret i1 %umul.ov.not
Done: 1
Optimization is correct!
```
Note that this is inverted from what we have in a previous patch,
here we are looking for the inverted overflow bit.
And that inversion is kinda problematic - given this particular
pattern we neither hoist that `not` closer to `ret` (then the pattern
would have been identical to the one without inversion,
and would have been handled by the previous patch), neither
do the opposite transform. But regardless, we should handle this too.
I've filled [[ https://bugs.llvm.org/show_bug.cgi?id=42720 | PR42720 ]].
Reviewers: nikic, spatel, xbolva00, RKSimon
Reviewed By: spatel
Subscribers: hiraditya, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D65151
llvm-svn: 370351
Summary:
Now that with D65143/D65144 we've produce `@llvm.umul.with.overflow`,
and with D65147 we've flattened the CFG, we now can see that
the guard may have been there to prevent division by zero is redundant.
We can simply drop it:
```
----------------------------------------
Name: no overflow and not zero
%iszero = icmp ne i4 %y, 0
%umul = umul_overflow i4 %x, %y
%umul.ov = extractvalue {i4, i1} %umul, 1
%retval.0 = and i1 %iszero, %umul.ov
ret i1 %retval.0
=>
%iszero = icmp ne i4 %y, 0
%umul = umul_overflow i4 %x, %y
%umul.ov = extractvalue {i4, i1} %umul, 1
%retval.0 = and i1 %iszero, %umul.ov
ret %umul.ov
Done: 1
Optimization is correct!
```
Reviewers: nikic, spatel, xbolva00
Reviewed By: spatel
Subscribers: hiraditya, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D65150
llvm-svn: 370350
The code we had isSafeToLoadUnconditionally was blatantly wrong. This function takes a "Size" argument which is supposed to describe the span loaded from. Instead, the code use the size of the pointer passed (which may be unrelated!) and only checks that span. For any Size > LoadSize, this can and does lead to miscompiles.
Worse, the generic code just a few lines above correctly handles the cases which *are* valid. So, let's delete said code.
Removing this code revealed two issues:
1) As noted by jdoerfert the removed code incorrectly handled external globals. The test update in SROA is to stop testing incorrect behavior.
2) SROA was confusing bytes and bits, but this wasn't obvious as the Size parameter was being essentially ignored anyway. Fixed.
Differential Revision: https://reviews.llvm.org/D66778
llvm-svn: 370102
Summary:
We already use the fact that an object with known size X does not alias
another objection of size Y > X before. With this commit, we use
dereferenceability information to determine a lower bound for Y and not
only rely on the user provided query size.
The result for @global_and_deref_arg_2() and @local_and_deref_ret_2()
in test/Analysis/BasicAA/dereferenceable.ll improved with this patch.
Reviewers: asbirlea, chandlerc, hfinkel, sanjoy
Subscribers: hiraditya, bollu, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D66157
llvm-svn: 369786
Given an instruction I, the MustBeExecutedContextExplorer allows to
easily traverse instructions that are guaranteed to be executed whenever
I is. For now, these instruction have to be statically "after" I, in
the same or different basic blocks.
This patch also adds a pass which prints the must-be-executed-context
for each instruction in a module. It is used to test the
MustBeExecutedContextExplorer, for now on the examples given in the
class comment of the MustBeExecutedIterator.
Differential Revision: https://reviews.llvm.org/D65186
llvm-svn: 369765
I noticed another instance of the issue where references to aliases were
being replaced with aliasees, this time in InstCombine. In the instance that
I saw it turned out to be only a QoI issue (a symbol ended up being missing
from the symbol table due to the last reference to the alias being removed,
preventing HWASAN from symbolizing a global reference), but it could easily
have manifested as incorrect behaviour.
Since this is the third such issue encountered (previously: D65118, D65314)
it seems to be time to address this common error/QoI issue once and for all
and make the strip* family of functions not look through aliases.
Includes a test for the specific issue that I saw, but no doubt there are
other similar bugs fixed here.
As with D65118 this has been tested to make sure that the optimization isn't
load bearing. I built Clang, Chromium for Linux, Android and Windows as well
as the test-suite and there were no size regressions.
Differential Revision: https://reviews.llvm.org/D66606
llvm-svn: 369697
Summary:
Add a flag to the FunctionToLoopAdaptor that allows enabling MemorySSA only for the loop pass managers that are known to preserve it.
If an LPM is known to have only loop transforms that *all* preserve MemorySSA, then use MemorySSA if `EnableMSSALoopDependency` is set.
If an LPM has loop passes that do not preserve MemorySSA, then the flag passed is `false`, regardless of the value of `EnableMSSALoopDependency`.
When using a custom loop pass pipeline via `passes=...`, use keyword `loop` vs `loop-mssa` to use MemorySSA in that LPM. If a loop that does not preserve MemorySSA is added while using the `loop-mssa` keyword, that's an error.
Add the new `loop-mssa` keyword to a few tests where a difference occurs when enabling MemorySSA.
Reviewers: chandlerc
Subscribers: mehdi_amini, Prazek, george.burgess.iv, sanjoy.google, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D66376
llvm-svn: 369548
Summary:
When inserting a new Def, and inserting Phis in the IDF when needed,
also mark the already existing Phis in the IDF as non-optimized, since
these may need fixing as well.
In the test attached, there is a Phi in the IDF that happens to be
trivial, and is wrongfully removed by the call to getLastDef that
follows. This is a valid situation and the existing IDF Phis need to
marked as "may need fixing" as well.
Resolves PR43044.
Reviewers: george.burgess.iv
Subscribers: Prazek, sanjoy.google, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D66495
llvm-svn: 369464
Summary:
CaptureTracker subclasses might have better dereferenceability
information which allows null pointer checks to be no-capturing.
The first user will be D59922.
Reviewers: sanjoy, hfinkel, aykevl, sstefan1, uenoku, xbolva00
Subscribers: hiraditya, bollu, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D66371
llvm-svn: 369305
Summary:
Simplify the API using Optional<> and address comments in
https://reviews.llvm.org/D66165
Reviewers: vitalybuka
Subscribers: hiraditya, llvm-commits, ostannard, pcc
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D66317
llvm-svn: 369300
Summary:
When inserting uses from outside the MemorySSA creation, we don't
normally need to rename uses, based on the assumption that there will be
no inserted Phis (if Def existed that required a Phi, that Phi already
exists). However, when dealing with unreachable blocks, MemorySSA will
optimize away Phis whose incoming blocks are unreachable, and these Phis end
up being re-added when inserting a Use.
There are two potential solutions here:
1. Analyze the inserted Phis and clean them up if they are unneeded
(current method for cleaning up trivial phis does not cover this)
2. Leave the Phi in place and rename uses, the same way as whe inserting
defs.
This patch use approach 2.
Resolves first test in PR42940.
Reviewers: george.burgess.iv
Subscribers: Prazek, sanjoy.google, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D66033
llvm-svn: 369291
Summary:
Before we required the comparison against null to be "canonical", hence
null to be operand #1. This patch allows null to be in either operand,
similar to the handling of loaded globals that follows.
Reviewers: sanjoy, hfinkel, aykevl, sstefan1, uenoku
Subscribers: hiraditya, bollu, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D66321
llvm-svn: 369158
If they're left in the cache then they can't be removed efficiently when the
cache is notified to unlink a @llvm.assume call, and that can lead to values
from different functions entirely remaining there.
llvm-svn: 369091
Summary:
Currently we fail to compute known bits for recurrences where the
first incoming value is the start value of the recurrence.
Instead of exiting the loop when the first incoming value is not
the step of the recurrence, continue to check the second incoming
value.
The original code uses a loop to handle both cases, but incorrectly
exits instead of continuing.
Reviewers: lebedev.ri, spatel, nikic
Reviewed By: lebedev.ri
Subscribers: hiraditya, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D66216
llvm-svn: 369088
The verification I added has overly restrictive asserts.
Unreachable blocks can have any incoming value in practice, after an
update due to a "replaceAllUses" call when the repalced entry is
LiveOnEntry.
llvm-svn: 369050
For indirect call sites having a small set of possible callees,
!callees metadata can be used to indicate what those callees are.
This patch updates the call graph and lazy call graph analyses so
that they consider this metadata when encountering call sites. For
the call graph, it adds a new external call graph node to the graph
for each unique !callees metadata node. A call graph edge connects
an indirect call site with the external node associated with the
!callees metadata that is attached to it. And there is an edge from
this external node to each of the callees indicated by the metadata.
Similarly, for the lazy call graph, the patch adds Ref edges from a
caller to the possible callees indicated by the metadata.
The primary purpose of the patch is to facilitate iterating over the
functions in a module such that all of the callees indicated by a
given !callees metadata node will be visited prior to the functions
containing call sites annotated by that node. This property is
required by optimizations performing a bottom-up traversal of the
SCC DAG. For example, the inliner can be made to inline through an
indirect call. If the call site is annotated with !callees metadata,
this patch ensures that the inliner will have visited all of the
callees prior to the caller, allowing it to reliably compute the
cost of inlining one or more of the potential callees.
Original patch by @mssimpso. I've made some small changes to get it
to apply, build, and pass tests on the top of tree, as well as
some minor tweaks to formatting and functionality.
Subscribers: mehdi_amini, hiraditya, llvm-commits, mssimpso
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D39339
llvm-svn: 369025
Now that we've moved to C++14, we no longer need the llvm::make_unique
implementation from STLExtras.h. This patch is a mechanical replacement
of (hopefully) all the llvm::make_unique instances across the monorepo.
llvm-svn: 369013
Some uses of getArgumentAliasingToReturnedPointer and
isIntrinsicReturningPointerAliasingArgumentWithoutCapturing require the
calls/intrinsics to preserve the nullness of the argument.
For alias analysis, the nullness property does not really come into
play.
This patch explicitly sets it to true. In D61669, the alias analysis
uses will be switched to not require preserving nullness.
Reviewers: nlopes, efriedma, hfinkel, sanjoy, aqjune, jdoerfert
Reviewed By: jdoerfert
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D64150
llvm-svn: 368993
I'm planning on handling intrinsics that will benefit from checking
the address space enums. Don't bother moving the address collection
for now, since those won't need th enums.
llvm-svn: 368895
Use isGuaranteedToTransferExecutionToSuccessor() instead of
isSafeToSpeculativelyExecute() when seeing whether we can propagate
the information in an assume backwards in isValidAssumeForContext().
The latter is more general - it also allows arbitrary loads/stores -
and is also the condition we want: if our assume is guaranteed to
execute, its condition not holding would be UB.
Original patch by arielb1.
Differential Revision: https://reviews.llvm.org/D37215
llvm-svn: 368723
This pass is a port of the according pass from the HSAIL compiler.
It parses printf calls and setup runtime printf buffer.
After that it copies printf arguments to the buffer and fills in
module metadata for runtime.
Differential Revision: https://reviews.llvm.org/D24035
llvm-svn: 368592
Introducing non-global control for default block-scan-limit in MemDep analysis.
Useful when there are many compilations per initialized LLVM instance (e.g. JIT).
Reviewed By: asbirlea
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D65806
llvm-svn: 368502
Summary: Implement a new analysis to estimate the number of cache lines
required by a loop nest.
The analysis is largely based on the following paper:
Compiler Optimizations for Improving Data Locality
By: Steve Carr, Katherine S. McKinley, Chau-Wen Tseng
http://www.cs.utexas.edu/users/mckinley/papers/asplos-1994.pdf
The analysis considers temporal reuse (accesses to the same memory
location) and spatial reuse (accesses to memory locations within a cache
line). For simplicity the analysis considers memory accesses in the
innermost loop in a loop nest, and thus determines the number of cache
lines used when the loop L in loop nest LN is placed in the innermost
position.
The result of the analysis can be used to drive several transformations.
As an example, loop interchange could use it determine which loops in a
perfect loop nest should be interchanged to maximize cache reuse.
Similarly, loop distribution could be enhanced to take into
consideration cache reuse between arrays when distributing a loop to
eliminate vectorization inhibiting dependencies.
The general approach taken to estimate the number of cache lines used by
the memory references in the inner loop of a loop nest is:
Partition memory references that exhibit temporal or spatial reuse into
reference groups.
For each loop L in the a loop nest LN: a. Compute the cost of the
reference group b. Compute the 'cache cost' of the loop nest by summing
up the reference groups costs
For further details of the algorithm please refer to the paper.
Authored By: etiotto
Reviewers: hfinkel, Meinersbur, jdoerfert, kbarton, bmahjour, anemet,
fhahn
Reviewed By: Meinersbur
Subscribers: reames, nemanjai, MaskRay, wuzish, Hahnfeld, xusx595,
venkataramanan.kumar.llvm, greened, dmgreen, steleman, fhahn, xblvaOO,
Whitney, mgorny, hiraditya, mgrang, jsji, llvm-commits
Tag: LLVM
Differential Revision: https://reviews.llvm.org/D63459
llvm-svn: 368439
The matchSelectPattern code can match patterns like (x >= 0) ? x : -x
for absolute value. But it can also match ((x-y) >= 0) ? (x-y) : (y-x).
If the latter form was matched we can only use the nsw flag if its
set on both subtracts.
This match makes sure we're looking at the former case only.
Differential Revision: https://reviews.llvm.org/D65692
llvm-svn: 368195
Without this patch computeConstantDifference returns None for cases like
these:
computeConstantDifference(%x, %x)
computeConstantDifference({%x,+,16}, {%x,+,16})
Differential Revision: https://reviews.llvm.org/D65474
llvm-svn: 368193
As discussed in PR42696:
https://bugs.llvm.org/show_bug.cgi?id=42696
...but won't help that case yet.
We have an odd situation where a select operand equivalence fold was
implemented in InstSimplify when it could have been done more generally
in InstCombine if we allow dropping of {nsw,nuw,exact} from a binop operand.
Here's an example:
https://rise4fun.com/Alive/Xplr
%cmp = icmp eq i32 %x, 2147483647
%add = add nsw i32 %x, 1
%sel = select i1 %cmp, i32 -2147483648, i32 %add
=>
%sel = add i32 %x, 1
I've left the InstSimplify code in place for now, but my guess is that we'd
prefer to remove that as a follow-up to save on code duplication and
compile-time.
Differential Revision: https://reviews.llvm.org/D65576
llvm-svn: 367695
Summary:
While there is always a `Value::replaceAllUsesWith()`,
sometimes the replacement needs to be conditional.
I have only cleaned a few cases where `replaceUsesWithIf()`
could be used, to both add test coverage,
and show that it is actually useful.
Reviewers: jdoerfert, spatel, RKSimon, craig.topper
Reviewed By: jdoerfert
Subscribers: dschuff, sbc100, jgravelle-google, hiraditya, aheejin, george.burgess.iv, asbirlea, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D65528
llvm-svn: 367548
Summary:
Verify that the incoming defs into phis are the last defs from the
respective incoming blocks.
When moving blocks, insertDef must RenameUses. Adding this verification
makes GVNHoist tests fail that uncovered this issue.
Reviewers: george.burgess.iv
Subscribers: jlebar, Prazek, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D63147
llvm-svn: 367451
Summary:
LoopRotate may simplify instructions, leading to the new instructions not having memory accesses created for them.
Allow this behavior, by allowing the new access to be null when the template is null, and looking upwards for the proper defined access when dealing with simplified instructions.
Reviewers: george.burgess.iv
Subscribers: jlebar, Prazek, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D65338
llvm-svn: 367352
Summary:
In D37215, AssumeLikeInstruction are regarded as `willreturn`. In this patch, annotation is added to those which don't have `willreturn` now(`sideeffect, object_size, experimental_widenable_condition`).
Reviewers: jdoerfert, nikic, sstefan1
Reviewed By: nikic
Subscribers: hiraditya, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D65455
llvm-svn: 367342
LoopInfo can be easily preserved by passing it to the functions that
modify the CFG (SplitCriticalEdge and MergeBlockIntoPredecessor.
SplitCriticalEdge also preserves LoopSimplify and LCSSA form when when passing in
LoopInfo. The test case shows that we preserve LoopSimplify and
LoopInfo. Adding addPreservedID(LCSSAID) did not preserve LCSSA for some
reason.
Also I am not sure if it is possible to preserve those in the new pass
manager, as they aren't analysis passes.
Reviewers: reames, hfinkel, davide, jdoerfert
Reviewed By: jdoerfert
Differential Revision: https://reviews.llvm.org/D65137
llvm-svn: 367332
Summary: As clarified in D53184, volatile load and store do not trap. Therefore, we should remove volatile checks for instructions in `isGuaranteedToTransferExecutionToSuccessor`.
Reviewers: jdoerfert, efriedma, nikic
Reviewed By: nikic
Subscribers: hiraditya, jfb, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D65375
llvm-svn: 367226
Summary:
The existing isDivergent(Value) methods query whether a value is
divergent at its definition. However even if a value is uniform at its
definition, a use of it in another basic block can be divergent because
of divergent control flow between the def and the use.
This patch adds new isDivergent(Use) methods to DivergenceAnalysis,
LegacyDivergenceAnalysis and GPUDivergenceAnalysis.
This might allow D63953 or other similar workarounds to be removed.
Reviewers: alex-t, nhaehnle, arsenm, rtaylor, rampitec, simoll, jingyue
Reviewed By: nhaehnle
Subscribers: jfb, jvesely, wdng, hiraditya, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D65141
llvm-svn: 367218
Summary:
This is the first patch for the loop guard. We introduced
getLoopGuardBranch() and isGuarded().
This currently only works on simplified loop, as it requires a preheader
and a latch to identify the guard.
It will work on loops of the form:
/// GuardBB:
/// br cond1, Preheader, ExitSucc <== GuardBranch
/// Preheader:
/// br Header
/// Header:
/// ...
/// br Latch
/// Latch:
/// br cond2, Header, ExitBlock
/// ExitBlock:
/// br ExitSucc
/// ExitSucc:
Prior discussions leading upto the decision to introduce the loop guard
API: http://lists.llvm.org/pipermail/llvm-dev/2019-May/132607.html
Reviewer: reames, kbarton, hfinkel, jdoerfert, Meinersbur, dmgreen
Reviewed By: reames
Subscribers: wuzish, hiraditya, jsji, llvm-commits, bmahjour, etiotto
Tag: LLVM
Differential Revision: https://reviews.llvm.org/D63885
llvm-svn: 367033
Summary:
SimplifyFPBinOp is a variant of SimplifyBinOp that lets you specify
fast math flags, but the name is misleading because both functions
can simplify both FP and non-FP ops. Instead, overload SimplifyBinOp
so that you can optionally specify fast math flags.
Likewise for SimplifyFPUnOp.
Reviewers: spatel
Reviewed By: spatel
Subscribers: xbolva00, cameron.mcinally, eraman, hiraditya, haicheng, zzheng, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D64902
llvm-svn: 366902
It is not safe in general to replace an alias in a GEP with its aliasee
if the alias can be replaced with another definition (i.e. via strong/weak
resolution (linkonce_odr) or via symbol interposition (default visibility
in ELF)) while the aliasee cannot. An example of how this can go wrong is
in the included test case.
I was concerned that this might be a load-bearing misoptimization (it's
possible for us to use aliases to share vtables between base and derived
classes, and on Windows, vtable symbols will always be aliases in RTTI
mode, so this change could theoretically inhibit trivial devirtualization
in some cases), so I built Chromium for Linux and Windows with and without
this change. The file sizes of the resulting binaries were identical, so it
doesn't look like this is going to be a problem.
Differential Revision: https://reviews.llvm.org/D65118
llvm-svn: 366754
Summary:
- As the pointer stripping now tracks through `addrspacecast`, prepare
to handle the bit-width difference from the result pointer.
Reviewers: jdoerfert
Subscribers: jvesely, nhaehnle, hiraditya, arphaman, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D64928
llvm-svn: 366470
Summary:
LoopInfoWrapperPass::verify uses DT, which means DT must be alive
even if it has no direct users.
Fixes a crash in expensive checks mode.
Reviewers: pcc, leonardchan
Subscribers: hiraditya, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D64896
llvm-svn: 366388
Implement IR intrinsics for stack tagging. Generated code is very
unoptimized for now.
Two special intrinsics, llvm.aarch64.irg.sp and llvm.aarch64.tagp are
used to implement a tagged stack frame pointer in a virtual register.
Differential Revision: https://reviews.llvm.org/D64172
llvm-svn: 366360
Summary:
Since the target has no significant advantage of vectorization,
vector instructions bous threshold bonus should be optional.
amdgpu-inline-arg-alloca-cost parameter default value and the target
InliningThresholdMultiplier value tuned then respectively.
Reviewers: arsenm, rampitec
Subscribers: kzhuravl, jvesely, wdng, nhaehnle, yaxunl, dstuttard, tpr, t-tye, eraman, hiraditya, haicheng, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D64642
llvm-svn: 366348
Summary:
- As the pointer stripping could trace through `addrspacecast` now, need
to sext/trunc the offset to ensure it has the same width as the
pointer after stripping.
Reviewers: jdoerfert
Subscribers: hiraditya, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D64768
llvm-svn: 366162
Summary:
There is currently a correctness issue when unrolling loops containing
callbr's where their indirect targets are being updated correctly to the
newly created labels, but their operands are not. This manifests in
unrolled loops where the second and subsequent copies of callbr
instructions have blockaddresses of the label from the first instance of
the unrolled loop, which would result in nonsensical runtime control
flow.
For now, conservatively do not unroll the loop. In the future, I think
we can pursue unrolling such loops provided we transform the cloned
callbr's operands correctly.
Such a transform and its legalities are being discussed in:
https://reviews.llvm.org/D64101
Link: https://bugs.llvm.org/show_bug.cgi?id=42489
Link: https://groups.google.com/forum/#!topic/clang-built-linux/z-hRWP9KqPI
Reviewers: fhahn, hfinkel, efriedma
Reviewed By: fhahn, hfinkel, efriedma
Subscribers: efriedma, hiraditya, zzheng, dmgreen, llvm-commits, pirama, kees, nathanchance, E5ten, craig.topper, chandlerc, glider, void, srhines
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D64368
llvm-svn: 366130
Summary: Vector of the same value with few undefs will sill be considered "Bytewise"
Reviewers: eugenis, pcc, jfb
Reviewed By: jfb
Subscribers: dexonsmith, hiraditya, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D64031
llvm-svn: 365971
Summary:
This helps with more efficient use of memset for pattern initialization
From @pcc prototype for -ftrivial-auto-var-init=pattern optimizations
Binary size change on CTMark, (with -fuse-ld=lld -Wl,--icf=all, similar results with default linker options)
```
master patch diff
Os 8.238864e+05 8.238864e+05 0.0
O3 1.054797e+06 1.054797e+06 0.0
Os zero 8.292384e+05 8.292384e+05 0.0
O3 zero 1.062626e+06 1.062626e+06 0.0
Os pattern 8.579712e+05 8.338048e+05 -0.030299
O3 pattern 1.090502e+06 1.067574e+06 -0.020481
```
Zero vs Pattern on master
```
zero pattern diff
Os 8.292384e+05 8.579712e+05 0.036578
O3 1.062626e+06 1.090502e+06 0.025124
```
Zero vs Pattern with the patch
```
zero pattern diff
Os 8.292384e+05 8.338048e+05 0.003333
O3 1.062626e+06 1.067574e+06 0.003193
```
Reviewers: pcc, eugenis
Subscribers: hiraditya, cfe-commits, llvm-commits
Tags: #clang, #llvm
Differential Revision: https://reviews.llvm.org/D63967
llvm-svn: 365858
The interface predates CallBase, so both it and implementation were
significantly more complicated than they needed to be. There was even
some redundancy that could be eliminated.
Should also help with OpaquePointers by not trying to derive a
function's type from it's PointerType.
llvm-svn: 365767
This patch replaces the three almost identical "strip & accumulate"
implementations for constant pointer offsets with a single one,
combining the respective functionalities. The old interfaces are kept
for now.
Differential Revision: https://reviews.llvm.org/D64468
llvm-svn: 365723
Summary:
We will need to handle IntToPtr which I will submit in a separate patch as it's
not going to be NFC.
Reviewers: eugenis, pcc
Reviewed By: eugenis
Subscribers: hiraditya, cfe-commits, llvm-commits
Tags: #clang, #llvm
Differential Revision: https://reviews.llvm.org/D63940
llvm-svn: 365709
This makes the functions in Loads.h require a type to be specified
independently of the pointer Value so that when pointers have no structure
other than address-space, it can still do its job.
Most callers had an obvious memory operation handy to provide this type, but a
SROA and ArgumentPromotion were doing more complicated analysis. They get
updated to merge the properties of the various instructions they were
considering.
llvm-svn: 365468
This patch adds a function attribute, nofree, to indicate that a function does
not, directly or indirectly, call a memory-deallocation function (e.g., free,
C++'s operator delete).
Reviewers: jdoerfert
Differential Revision: https://reviews.llvm.org/D49165
llvm-svn: 365336
It's possible that some function can load and store the same
variable using the same constant expression:
store %Derived* @foo, %Derived** bitcast (%Base** @bar to %Derived**)
%42 = load %Derived*, %Derived** bitcast (%Base** @bar to %Derived**)
The bitcast expression was mistakenly cached while processing loads,
and never examined later when processing store. This caused @bar to
be mistakenly treated as read-only variable. See load-store-caching.ll.
llvm-svn: 365188
This reverts r365040 (git commit 5cacb91475)
Speculatively reverting, since this appears to have broken check-lld on
Linux. Partial analysis in https://crbug.com/981168.
llvm-svn: 365097
We haven't changed the set of users, just specialized an operand for those users. Given that, the previous wrap flags must still be correct.
Sorry for the lack of test case. Noticed this while working on something else, and haven't figured out to exercise this standalone.
llvm-svn: 365053
On some occasions ReuseOrCreateCast may convert previously
expanded value to undefined. That value may be passed by
SCEVExpander as an argument to InsertBinop making IV chain
undefined.
Differential revision: https://reviews.llvm.org/D63928
llvm-svn: 365009
This reverts r364422 (git commit 1a3dc76186)
The inlining cost calculation is incorrect, leading to stack overflow due to large stack frames from heavy inlining.
llvm-svn: 365000
Summary:
If LTOUnit splitting is disabled, the module summary analysis computes
the summary information necessary to perform single implementation
devirtualization during the thin link with the index and no IR. The
information collected from the regular LTO IR in the current hybrid WPD
algorithm is summarized, including:
1) For vtable definitions, record the function pointers and their offset
within the vtable initializer (subsumes the information collected from
IR by tryFindVirtualCallTargets).
2) A record for each type metadata summarizing the vtable definitions
decorated with that metadata (subsumes the TypeIdentiferMap collected
from IR).
Also added are the necessary bitcode records, and the corresponding
assembly support.
The follow-on index-based WPD patch is D55153.
Depends on D53890.
Reviewers: pcc
Subscribers: mehdi_amini, Prazek, inglorion, eraman, steven_wu, dexonsmith, arphaman, llvm-commits
Differential Revision: https://reviews.llvm.org/D54815
llvm-svn: 364960
I'm currently working on a GSoC project that aims to improve the the bug reports
of the analyzer. The main heuristic I plan to use is to explain values that are
a control dependency of the bug location better.
01 bool b = messyComputation();
02 int i = 0;
03 if (b) // control dependency of the bug site, let's explain why we assume val
04 // to be true
05 10 / i; // warn: division by zero
Because of this, I'd like to generalize IDFCalculator so that I could use it for
Clang's CFG: D62883.
In detail:
* Rename IDFCalculator to IDFCalculatorBase, make it take a general CFG node
type as a template argument rather then strictly BasicBlock (but preserve
ForwardIDFCalculator and ReverseIDFCalculator)
* Move IDFCalculatorBase from llvm/include/llvm/Analysis to
llvm/include/llvm/Support (but leave the BasicBlock variants in
llvm/include/llvm/Analysis)
* clang-format the file since this patch messes up git blame anyways
* Change typedef to using
* Add the new type ChildrenGetterTy, and store an instance of it in
IDFCalculatorBase. This is important because I'll have to specialize it for
Clang's CFG to filter out nullpointer successors, similarly to D62507.
Differential Revision: https://reviews.llvm.org/D63389
llvm-svn: 364911
The `willreturn` function attribute guarantees that a function call will
come back to the call site if the call is also known not to throw.
Therefore, this attribute can be used in
`isGuaranteedToTransferExecutionToSuccessor`.
Patch by Hideto Ueno (@uenoku)
Reviewers: jdoerfert, sstefan1
Reviewed By: jdoerfert
Subscribers: hiraditya, jfb, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D63372
llvm-svn: 364580
The previous output was next to useless if *any* exit was not computable. If we have more than one exit, show the exit count for each so that it's easier to see what's going from with SCEV analysis when debugging.
llvm-svn: 364579
Summary:
Doing better separation of Cost and Threshold.
Cost counts the abstract complexity of live instructions, while Threshold is an upper bound of complexity that inlining is comfortable to pay.
There are two parts:
- huge 15K last-call-to-static bonus is no longer subtracted from Cost
but rather is now added to Threshold.
That makes much more sense, as the cost of inlining (Cost) is not changed by the fact
that internal function is called once. It only changes the likelyhood of this inlining
being profitable (Threshold).
- bonus for calls proved-to-be-inlinable into callee is no longer subtracted from Cost
but added to Threshold instead.
While calculations are somewhat different, overall InlineResult should stay the same since Cost >= Threshold compares the same.
Reviewers: eraman, greened, chandlerc, yrouban, apilipenko
Reviewed By: apilipenko
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D60740
llvm-svn: 364422
Summary:
Handle smul.fix.sat in the scalarizer. This is done by
adding smul.fix.sat to the set of "isTriviallyVectorizable"
intrinsics.
The addition of smul.fix.sat in isTriviallyVectorizable and
hasVectorInstrinsicScalarOpd can also be seen as a preparation
to be able to use hasVectorInstrinsicScalarOpd in ConstantFolding.
Reviewers: rengolin, RKSimon, dblaikie
Reviewed By: rengolin
Subscribers: hiraditya, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D63704
llvm-svn: 364177
As discussed in PR42314:
https://bugs.llvm.org/show_bug.cgi?id=42314
Improving the canonicalization for these patterns:
rL363956
...means we should adjust/enhance the related simplification.
https://rise4fun.com/Alive/w1cp
Name: isPow2 or zero
%x = and i32 %xx, 2048
%a = add i32 %x, -1
%r = and i32 %a, %x
=>
%r = i32 0
llvm-svn: 363997
Summary:
This is unfortunately needed for correctness, if we are to extend the tolerance of the update API to the way simple loop unswitch is doing cloning.
In simple loop unswitch (as opposed to loop unswitch), not all blocks are cloned. This can create unreachable cloned blocks (no predecessor), which are later cleaned up.
In MemorySSA, the APIs for supporting these kind of updates (clone + update exit blocks), make certain assumption on the integrity of the CFG. When cloning, if something was not cloned, it's values in MemorySSA default to LiveOnEntry. When updating exit blocks, it is safe to assume that we can first insert phis in the blocks merging two clones, then add additional phis in the IDF of the blocks that received phis. This no longer holds true if one of the clones being merged comes from an unreachable block. We'd conservatively need to add all phis before filling in their incoming definitions. In practice this restriction can be relaxed if we clean up trivial phis after the first round of insertion.
Reviewers: george.burgess.iv
Subscribers: jlebar, Prazek, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D63354
llvm-svn: 363880
Summary:
When computing IDF for insert updates, ensure we use the snapshot CFG offered by GraphDiff.
Caught by D63389.
Reviewers: kuhar, george.burgess.iv
Subscribers: jlebar, Prazek, llvm-commits, Szelethus
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D63443
llvm-svn: 363879
Summary:
This patch teaches ConstantFolding to constant fold
both scalar and vector variants of llvm.smul.fix and
llvm.smul.fix.sat.
As described in the LangRef rounding is unspecified for
these instrinsics. If the result cannot be represented
exactly the default behavior in ConstantFolding is to
round down towards negative infinity. If a target has a
preferred rounding that is different some kind of target
hook would be needed (same strategy as used by the
SelectionDAG legalizer).
Reviewers: nikic, leonardchan, RKSimon
Reviewed By: leonardchan
Subscribers: hiraditya, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D63385
llvm-svn: 363811
This patch splits ConstantFoldScalarCall into several
functions.
Benefits:
- Reduces indentation levels and avoids long if-statements.
- Makes it easier to add support for > 3 operands.
llvm-svn: 363810
Summary:
The test case does an (out of bounds) load from a global constant with
type <3 x float>. InstSimplify tried to turn this into an integer load
of the whole alloc size of the vector, which is 128 bits due to
alignment padding, and then bitcast this to <3 x vector> which failed
an assertion due to the type size mismatch.
The fix is to do an integer load of the normal size of the vector, with
no alignment padding.
Reviewers: tpr, arsenm, majnemer, dstuttard
Reviewed By: arsenm
Subscribers: hfinkel, wdng, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D63375
llvm-svn: 363784
Inter-block localization is the same as what currently happens, except now it
only runs on the entry block because that's where the problematic constants with
long live ranges come from.
The second phase is a new intra-block localization phase which attempts to
re-sink the already localized instructions further right before one of the
multiple uses.
One additional change is to also localize G_GLOBAL_VALUE as they're constants
too. However, on some targets like arm64 it takes multiple instructions to
materialize the value, so some additional heuristics with a TTI hook have been
introduced attempt to prevent code size regressions when localizing these.
Overall, these changes improve CTMark code size on arm64 by 1.2%.
Full code size results:
Program baseline new diff
------------------------------------------------------------------------------
test-suite...-typeset/consumer-typeset.test 1249984 1217216 -2.6%
test-suite...:: CTMark/ClamAV/clamscan.test 1264928 1232152 -2.6%
test-suite :: CTMark/SPASS/SPASS.test 1394092 1361316 -2.4%
test-suite...Mark/mafft/pairlocalalign.test 731320 714928 -2.2%
test-suite :: CTMark/lencod/lencod.test 1340592 1324200 -1.2%
test-suite :: CTMark/kimwitu++/kc.test 3853512 3820420 -0.9%
test-suite :: CTMark/Bullet/bullet.test 3406036 3389652 -0.5%
test-suite...ark/tramp3d-v4/tramp3d-v4.test 8017000 8016992 -0.0%
test-suite...TMark/7zip/7zip-benchmark.test 2856588 2856588 0.0%
test-suite...:: CTMark/sqlite3/sqlite3.test 765704 765704 0.0%
Geomean difference -1.2%
Differential Revision: https://reviews.llvm.org/D63303
llvm-svn: 363632
This patch really contains two pieces:
Teach SCEV how to fold a phi in the header of a loop to the value on the backedge when a) the backedge is known to execute at least once, and b) the value is safe to use globally within the scope dominated by the original phi.
Teach IndVarSimplify's rewriteLoopExitValues to allow loop invariant expressions which already exist (and thus don't need new computation inserted) even in loops where we can't optimize away other uses.
Differential Revision: https://reviews.llvm.org/D63224
llvm-svn: 363619
Summary:
LoopRotate doesn't create a faithful clone of an instruction, it may
simplify it beforehand. Hence the clone of an instruction that has a
MemoryDef associated may not be a definition, but a use or not a memory
alternig instruction.
Don't rely on the template when the clone may be simplified.
Reviewers: george.burgess.iv
Subscribers: jlebar, Prazek, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D63355
llvm-svn: 363597
Summary:
Add all MemoryPhis in IDF before filling in their incomign values.
Otherwise, a new Phi can be added that needs to become the incoming
value of another Phi.
Test fails the verification in verifyPrevDefInPhis.
Reviewers: george.burgess.iv
Subscribers: jlebar, Prazek, zzheng, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D63353
llvm-svn: 363590
When considering a loop containing nontemporal stores or loads for
vectorization, suppress the vectorization if the corresponding
vectorized store or load with the aligment of the original scaler
memory op is not supported with the nontemporal hint on the target.
This adds two new functions:
bool isLegalNTStore(Type *DataType, unsigned Alignment) const;
bool isLegalNTLoad(Type *DataType, unsigned Alignment) const;
to TTI, leaving the target independent default implementation as
returning true, but with overriding implementations for X86 that
check the legality based on available Subtarget features.
This fixes https://llvm.org/PR40759
Differential Revision: https://reviews.llvm.org/D61764
llvm-svn: 363581
Second functional change following on from rL362687. Pass the
NoWrapFlags from the MulExpr to InsertBinop when we're generating a
shl or mul.
Differential Revision: https://reviews.llvm.org/D61934
llvm-svn: 363540
Fix folds of addo and subo with an undef operand to be:
`@llvm.{u,s}{add,sub}.with.overflow` all fold to `{ undef, false }`,
as per LLVM undef rules.
Same for commuted variants.
Based on the original version of the patch by @nikic.
Fixes [[ https://bugs.llvm.org/show_bug.cgi?id=42209 | PR42209 ]]
Differential Revision: https://reviews.llvm.org/D63065
llvm-svn: 363522
Based on D59959, this switches SCEV to use unsigned/signed range
intersection based on the sign hint. This will prefer non-wrapping
ranges in the relevant domain. I've left the one intersection in
getRangeForAffineAR() to use the smallest intersection heuristic,
as there doesn't seem to be any obvious preference there.
Differential Revision: https://reviews.llvm.org/D60035
llvm-svn: 363490
with 'objc_arc_inert'
Those calls are no-ops, so they can be safely deleted.
rdar://problem/49839633
Differential Revision: https://reviews.llvm.org/D62433
llvm-svn: 363468
There is a circular dependency between SROA and InferAddressSpaces
today that requires running both multiple times in order to be able to
eliminate all simple allocas and addrspacecasts. InferAddressSpaces
can't remove addrspacecasts when written to memory, and SROA helps
move pointers out of memory.
This should avoid inserting new commuting addrspacecasts with GEPs,
since there are unresolved questions about pointer wrapping between
different address spaces.
For now, don't replace volatile operations that don't match the alloca
addrspace, as it would change the address space of the access. It may
be still OK to insert an addrspacecast from the new alloca, but be
more conservative for now.
llvm-svn: 363462
InsertBinop now accepts NoWrapFlags, so pass them through when
expanding a simple add expression.
This is the first re-commit of the functional changes from rL362687,
which was previously reverted.
Differential Revision: https://reviews.llvm.org/D61934
llvm-svn: 363364
I find the current documentation of poison somewhat confusing,
mainly because its use of "undefined behavior" doesn't seem to
align with our usual interpretation (of immediate UB). Especially
the sentence "any instruction that has a dependence on a poison
value has undefined behavior" is very confusing.
Clarify poison semantics by:
* Replacing the introductory paragraph with the standard rationale
for having poison values.
* Spelling out that instructions depending on poison return poison.
* Spelling out how we go from a poison value to immediate undefined
behavior and give the two examples we currently use in ValueTracking.
* Spelling out that side effects depending on poison are UB.
Differential Revision: https://reviews.llvm.org/D63044
llvm-svn: 363320
I recently got this wrong (again), and I'm sure I'm not the only one. Put a comment in the logical place someone would look to "fix" the obvious "missed optimization" which arrises based on the common misunderstanding. Hopefully, this will save others time. :)
llvm-svn: 363318
Summary:
The logic in EarlyCSE that looks through 'not' operations in the
predicate recognizes e.g. that `select (not (cmp sgt X, Y)), X, Y` is
equivalent to `select (cmp sgt X, Y), Y, X`. Without this change,
however, only the latter is recognized as a form of `smin X, Y`, so the
two expressions receive different hash codes. This leads to missed
optimization opportunities when the quadratic probing for the two hashes
doesn't happen to collide, and assertion failures when probing doesn't
collide on insertion but does collide on a subsequent table grow
operation.
This change inverts the order of some of the pattern matching, checking
first for the optional `not` and then for the min/max/abs patterns, so
that e.g. both expressions above are recognized as a form of `smin X, Y`.
It also adds an assertion to isEqual verifying that it implies equal
hash codes; this fires when there's a collision during insertion, not
just grow, and so will make it easier to notice if these functions fall
out of sync again. A new flag --earlycse-debug-hash is added which can
be used when changing the hash function; it forces hash collisions so
that any pair of values inserted which compare as equal but hash
differently will be caught by the isEqual assertion.
Reviewers: spatel, nikic
Reviewed By: spatel, nikic
Subscribers: lebedev.ri, arsenm, craig.topper, efriedma, hiraditya, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D62644
llvm-svn: 363274
SCEV does not propagate arguments through one-input Phis so as to make it easy for the SCEV expander (and related code) to preserve LCSSA. It's not entirely clear this restriction is neccessary, but for the moment it exists. For this reason, we don't analyze single-entry phi inputs. However it is possible that when an this input leaves the loop through LCSSA Phi, it is a provable constant. Missing that results in an order of optimization issue in loop exit value rewriting where we miss some oppurtunities based on order in which we visit sibling loops.
This patch teaches computeSCEVAtScope about this case. We can generalize it later, but so far we can only replace LCSSA Phis with their constant loop-exiting values. We should probably also add similiar logic directly in the SCEV construction path itself.
Patch by: mkazantsev (with revised commit message by me)
Differential Revision: https://reviews.llvm.org/D58113
llvm-svn: 363180
This case is slightly tricky, because loop distribution should be
allowed in some cases, and not others. As long as runtime dependency
checks don't need to be introduced, this should be OK. This is further
complicated by the fact that LoopDistribute partially ignores if LAA
says that vectorization is safe, and then does its own runtime pointer
legality checks.
Note this pass still does not handle noduplicate correctly, as this
should always be forbidden with it. I'm not going to bother trying to
fix it, as it would require more effort and I think noduplicate should
be removed.
https://reviews.llvm.org/D62607
llvm-svn: 363160
The capture was added in the first commit of https://reviews.llvm.org/D61934
when it was used. In the reland, the use was removed but the capture
wasn't removed.
llvm-svn: 363155
'Use wrap flags in InsertBinop' (rL362687) was reverted due to
miscompiles. This patch introduces the previous change to pass
no-wrap flags but now only FlagAnyWrap is passed.
Differential Revision: https://reviews.llvm.org/D61934
llvm-svn: 363147
The issue is that if we have a loop with multiple predecessors outside the loop, the code was expecting to merge them and only return if equal, but instead returned the first one seen.
I have no idea if this actually tripped anywhere. I noticed it by accident when reading the code and have no idea how to go about constructing a test case.
llvm-svn: 363112
We have the related getSplatValue() already in IR (see code just above the proposed addition).
But sometimes we only need to know that the value is a splat rather than capture the splatted
scalar value. Also, we have an isSplatValue() function already in SDAG.
Motivation - recent bugs that would potentially benefit from improved splat analysis in IR:
https://bugs.llvm.org/show_bug.cgi?id=37428https://bugs.llvm.org/show_bug.cgi?id=42174
Differential Revision: https://reviews.llvm.org/D63138
llvm-svn: 363106
Summary: After applying a set of insert updates, there may be trivial Phis left over. Clean them up.
Reviewers: george.burgess.iv
Subscribers: jlebar, Prazek, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D63033
llvm-svn: 363094
Summary:
The method `getLoopPassPreservedAnalyses` should not mark MemorySSA as
preserved, because it's being called in a lot of passes that do not
preserve MemorySSA.
Instead, mark the MemorySSA analysis as preserved by each pass that does
preserve it.
These changes only affect the new pass mananger.
Reviewers: chandlerc
Subscribers: mehdi_amini, jlebar, Prazek, george.burgess.iv, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D62536
llvm-svn: 363091
This is another step towards correcting our usage of fast-math-flags when applied on an fcmp.
In this case, we are checking for 'nnan' on the fcmp itself rather than the operand of
the fcmp. But I'm leaving that clause in until we're more confident that we can stop
relying on fcmp's FMF.
By using the more general "isKnownNeverNaN()", we gain a simplification shown on the
tests with 'uitofp' regardless of the FMF on the fcmp (uitofp never produces a NaN).
On the tests with 'fabs', we are now relying on the FMF for the call fabs instruction
in addition to the FMF on the fcmp.
This is a continuation of D62979 / rL362879.
llvm-svn: 362903
Pointers that are in-bounds (either through dereferenceable_or_null or
thorough a getelementptr inbounds) cannot be captured with a comparison
against null. There is no way to construct a pointer that is still in
bounds but also NULL.
This helps safe languages that insert null checks before load/store
instructions. Without this patch, almost all pointers would be
considered captured even for simple loads. With this patch, an icmp with
null will not be seen as escaping as long as certain conditions are met.
There was a lot of discussion about this patch. See the Phabricator
thread for detals.
Differential Revision: https://reviews.llvm.org/D60047
llvm-svn: 362900
This is 1 step towards correcting our usage of fast-math-flags when applied on an fcmp.
In this case, we are checking for 'nnan' on the fcmp itself rather than the operand of
the fcmp. But I'm leaving that clause in until we're more confident that we can stop
relying on fcmp's FMF.
By using the more general "isKnownNeverNaN()", we gain a simplification shown on the
tests with 'uitofp' regardless of the FMF on the fcmp (uitofp never produces a NaN).
On the tests with 'fabs', we are now relying on the FMF for the call fabs instruction
in addition to the FMF on the fcmp.
I'll update the 'ult' case below here as a follow-up assuming no problems here.
Differential Revision: https://reviews.llvm.org/D62979
llvm-svn: 362879
Patch which introduces a target-independent framework for generating
hardware loops at the IR level. Most of the code has been taken from
PowerPC CTRLoops and PowerPC has been ported over to use this generic
pass. The target dependent parts have been moved into
TargetTransformInfo, via isHardwareLoopProfitable, with
HardwareLoopInfo introduced to transfer information from the backend.
Three generic intrinsics have been introduced:
- void @llvm.set_loop_iterations
Takes as a single operand, the number of iterations to be executed.
- i1 @llvm.loop_decrement(anyint)
Takes the maximum number of elements processed in an iteration of
the loop body and subtracts this from the total count. Returns
false when the loop should exit.
- anyint @llvm.loop_decrement_reg(anyint, anyint)
Takes the number of elements remaining to be processed as well as
the maximum numbe of elements processed in an iteration of the loop
body. Returns the updated number of elements remaining.
llvm-svn: 362774
This adds support for unary fneg based on the implementation of BinaryOperator without the soft float FP cost.
Previously we would just delegate to visitUnaryInstruction. I think the only real change is that we will pass the FastMath flags to SimplifyFNeg now.
Differential Revision: https://reviews.llvm.org/D62699
llvm-svn: 362732
Summary: Dependence Analysis performs static checks to confirm validity
of delinearization. These checks often fail for 64-bit targets due to
type conversions and integer wrapping that prevent simplification of the
SCEV expressions. These checks would also fail at compile-time if the
lower bound of the loops are compile-time unknown.
For example:
void foo(int n, int m, int a[][m]) {
for (int i = 0; i < n; ++i)
for (int j = 0; j < m; ++j) {
a[i][j] = a[i+1][j-2];
}
}
opt -mem2reg -instcombine -indvars -loop-simplify -loop-rotate -inline
-pass-remarks=.* -debug-pass=Arguments
-da-permissive-validity-checks=false k3.ll -analyze -da
will produce the following by default:
da analyze - anti [* *|<]!
but will produce the following expected dependence vector if the
validity checks are disabled:
da analyze - consistent anti [1 -2]!
This revision will introduce a debug option that will leave the validity
checks in place by default, but allow them to be turned off. New tests
are added for cases where it cannot be proven at compile-time that the
individual subscripts stay in-bound with respect to a particular
dimension of an array. These tests enable the option to provide user
guarantee that the subscripts do not over/under-flow into other
dimensions, thereby producing more accurate dependence vectors.
For prior discussion on this topic, leading to this change, please see
the following thread:
http://lists.llvm.org/pipermail/llvm-dev/2019-May/132372.html
Reviewers: Meinersbur, jdoerfert, kbarton, dmgreen, fhahn
Reviewed By: Meinersbur, jdoerfert, dmgreen
Subscribers: fhahn, hiraditya, javed.absar, llvm-commits, Whitney,
etiotto
Tag: LLVM
Differential Revision: https://reviews.llvm.org/D62610
llvm-svn: 362711
If the given SCEVExpr has no (un)signed flags attached to it, transfer
these to the resulting instruction or use them to find an existing
instruction.
Differential Revision: https://reviews.llvm.org/D61934
llvm-svn: 362687
This patch allows current users of Value::stripPointerCasts() to force
the result of the function to have the same representation as the value
it was called on. This is useful in various cases, e.g., (non-)null
checks.
In this patch only a single call site was adjusted to fix an existing
misuse that would cause nonnull where they may be wrong. Uses in
attribute deduction and other areas, e.g., D60047, are to be expected.
For a discussion on this topic, please see [0].
[0] http://lists.llvm.org/pipermail/llvm-dev/2018-December/128423.html
Reviewers: hfinkel, arsenm, reames
Subscribers: wdng, hiraditya, bollu, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D61607
llvm-svn: 362545
The underlying ConstantRange functionality has been added in D60952,
D61207 and D61238, this just exposes it for LVI.
I'm switching the code from using a whitelist to a blacklist, as
we're down to one unsupported operation here (xor) and writing it
this way seems more obvious :)
Differential Revision: https://reviews.llvm.org/D62822
llvm-svn: 362519
This looks like an oversight as all the other binary operators are present.
Accidentally noticed while auditing places that need FNeg handling.
No test because as noted in the review it would be contrived and amount to "don't crash"
Differential Revision: https://reviews.llvm.org/D62790
llvm-svn: 362441
Summary: Fneg can be implemented with an xor rather than a function call so we don't need to add the function call overhead. This was pointed out in D62699
Reviewers: efriedma, cameron.mcinally
Reviewed By: efriedma
Subscribers: javed.absar, eraman, hiraditya, haicheng, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D62747
llvm-svn: 362304
When the object size argument is -1, no checking can be done, so calling the
_chk variant is unnecessary. We already did this for a bunch of these
functions.
rdar://50797197
Differential revision: https://reviews.llvm.org/D62358
llvm-svn: 362272
These can take a significant amount of time in some builds.
Suggested by Andrea Di Biagio.
Differential Revision: https://reviews.llvm.org/D62666
llvm-svn: 362219
In order to fold an always overflowing signed saturating add/sub,
we need to know in which direction the always overflow occurs.
This patch splits up AlwaysOverflows into AlwaysOverflowsLow and
AlwaysOverflowsHigh to pass through this information (but it is
not used yet).
Differential Revision: https://reviews.llvm.org/D62463
llvm-svn: 361858
Replace "unary operator" with "unary instruction" in visitUnaryInstruction since
we now have a UnaryOperator class which might needs its own visit function.
Fix a copy/paste in visitCastInst that appears to have been copied from
visitPtrToInt.
llvm-svn: 361794
Summary:
This reuses the getArithmeticInstrCost, but passes dummy values of the second
operand flags.
The X86 costs are wrong and can be improved in a follow up. I just wanted to
stop it from reporting an unknown cost first.
Reviewers: RKSimon, spatel, andrew.w.kaylor, cameron.mcinally
Reviewed By: spatel
Subscribers: hiraditya, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D62444
llvm-svn: 361788
Summary:
for.outer:
br for.inner
for.inner:
LI <loop invariant load instruction>
for.inner.latch:
br for.inner, for.outer.latch
for.outer.latch:
br for.outer, for.outer.exit
LI is a loop invariant load instruction that post dominate for.outer, so LI should be able to move out of the loop nest. However, there is a bug in allLoopPathsLeadToBlock().
Current algorithm of allLoopPathsLeadToBlock()
1. get all the transitive predecessors of the basic block LI belongs to (for.inner) ==> for.outer, for.inner.latch
2. if any successors of any of the predecessors are not for.inner or for.inner's predecessors, then return false
3. return true
Although for.inner.latch is for.inner's predecessor, but for.inner dominates for.inner.latch, which means if for.inner.latch is ever executed, for.inner should be as well. It should not return false for cases like this.
Author: Whitney (committed by xingxue)
Reviewers: kbarton, jdoerfert, Meinersbur, hfinkel, fhahn
Reviewed By: jdoerfert
Subscribers: hiraditya, jsji, llvm-commits, etiotto, bmahjour
Tags: #LLVM
Differential Revision: https://reviews.llvm.org/D62418
llvm-svn: 361762
The implementation in ValueTracking and ConstantRange are equally
powerful, reuse the one in ConstantRange, which will make this easier
to extend.
llvm-svn: 361723
Adds support for the uadd.sat family of intrinsics in LVI, based on
ConstantRange methods from D60946.
Differential Revision: https://reviews.llvm.org/D62447
llvm-svn: 361703
In LVI, calculate the range of extractvalue(op.with.overflow(%x, %y), 0)
as the range of op(%x, %y). This is mainly useful in conjunction with
D60650: If the result of the operation is extracted in a branch guarded
against overflow, then the value of %x will be appropriately constrained
and the result range of the operation will be calculated taking that
into account.
Differential Revision: https://reviews.llvm.org/D60656
llvm-svn: 361693
This was part of InstCombine, but it's better placed in
InstSimplify. InstCombine also had an unreachable but weaker
fold for insertelement with undef index, so that is deleted.
llvm-svn: 361559
Summary:
This PR extends the loop object with more utilities to get loop bounds, step, induction variable, and guard branch. There already exists passes which try to obtain the loop induction variable in their own pass, e.g. loop interchange. It would be useful to have a common area to get these information. Moreover, loop fusion (https://reviews.llvm.org/D55851) is planning to use getGuard() to extend the kind of loops it is able to fuse, e.g. rotated loop with non-constant upper bound, which would have a loop guard.
/// Example:
/// for (int i = lb; i < ub; i+=step)
/// <loop body>
/// --- pseudo LLVMIR ---
/// beforeloop:
/// guardcmp = (lb < ub)
/// if (guardcmp) goto preheader; else goto afterloop
/// preheader:
/// loop:
/// i1 = phi[{lb, preheader}, {i2, latch}]
/// <loop body>
/// i2 = i1 + step
/// latch:
/// cmp = (i2 < ub)
/// if (cmp) goto loop
/// exit:
/// afterloop:
///
/// getBounds
/// getInitialIVValue --> lb
/// getStepInst --> i2 = i1 + step
/// getStepValue --> step
/// getFinalIVValue --> ub
/// getCanonicalPredicate --> '<'
/// getDirection --> Increasing
/// getGuard --> if (guardcmp) goto loop; else goto afterloop
/// getInductionVariable --> i1
/// getAuxiliaryInductionVariable --> {i1}
/// isCanonical --> false
Committed on behalf of @Whitney (Whitney Tsang).
Reviewers: kbarton, hfinkel, dmgreen, Meinersbur, jdoerfert, syzaara, fhahn
Reviewed By: kbarton
Subscribers: tvvikram, bmahjour, etiotto, fhahn, jsji, hiraditya, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D60565
llvm-svn: 361517
Summary:
It was supposed that Ref LazyCallGraph::Edge's were being inserted by
inlining, but that doesn't seem to be the case. Instead, it seems that
there was no test for a blockaddress Constant in an instruction that
referenced the function that contained the instruction. Ex:
```
define void @f() {
%1 = alloca i8*, align 8
2:
store i8* blockaddress(@f, %2), i8** %1, align 8
ret void
}
```
When iterating blockaddresses, do not add the function they refer to
back to the worklist if the blockaddress is referring to the contained
function (as opposed to an external function).
Because blockaddress has sligtly different semantics than GNU C's
address of labels, there are 3 cases that can occur with blockaddress,
where only 1 can happen in GNU C due to C's scoping rules:
* blockaddress is within the function it refers to (possible in GNU C).
* blockaddress is within a different function than the one it refers to
(not possible in GNU C).
* blockaddress is used in to declare a global (not possible in GNU C).
The second case is tested in:
```
$ ./llvm/build/unittests/Analysis/AnalysisTests \
--gtest_filter=LazyCallGraphTest.HandleBlockAddress
```
This patch adjusts the iteration of blockaddresses in
LazyCallGraph::visitReferences to not revisit the blockaddresses
function in the first case.
The Linux kernel contains code that's not semantically valid at -O0;
specifically code passed to asm goto. It requires that asm goto be
inline-able. This patch conservatively does not attempt to handle the
more general case of inlining blockaddresses that have non-callbr users
(pr/39560).
https://bugs.llvm.org/show_bug.cgi?id=39560https://bugs.llvm.org/show_bug.cgi?id=40722https://github.com/ClangBuiltLinux/linux/issues/6https://reviews.llvm.org/rL212077
Reviewers: jyknight, eli.friedman, chandlerc
Reviewed By: chandlerc
Subscribers: george.burgess.iv, nathanchance, mgorny, craig.topper, mengxu.gatech, void, mehdi_amini, E5ten, chandlerc, efriedma, eraman, hiraditya, haicheng, pirama, llvm-commits, srhines
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D58260
llvm-svn: 361173
This is the sibling transform for rL360899 (D61691):
maxnum(X, GreaterC) == C --> false
maxnum(X, GreaterC) <= C --> false
maxnum(X, GreaterC) < C --> false
maxnum(X, GreaterC) >= C --> true
maxnum(X, GreaterC) > C --> true
maxnum(X, GreaterC) != C --> true
llvm-svn: 361118
minnum(X, LesserC) == C --> false
minnum(X, LesserC) >= C --> false
minnum(X, LesserC) > C --> false
minnum(X, LesserC) != C --> true
minnum(X, LesserC) <= C --> true
minnum(X, LesserC) < C --> true
maxnum siblings will follow if there are no problems here.
We should be able to perform some other combines when the constants
are equal or greater-than too, but that would go in instcombine.
We might also generalize this by creating an FP ConstantRange
(similar to what we do for integers).
Differential Revision: https://reviews.llvm.org/D61691
llvm-svn: 360899
Based on ConstantRange support added in D61084, we can now handle
abs and nabs select pattern flavors in LVI.
Differential Revision: https://reviews.llvm.org/D61794
llvm-svn: 360700
Summary:
Currently InductionBinOps are only saved for FP induction variables, the PR extends it with non FP induction variable, so user of IVDescriptors can query the InductionBinOps for integer induction variables.
The changes in hasUnsafeAlgebra() and getUnsafeAlgebraInst() are required for the existing LIT test cases to pass. As described in the comment of the two functions, one of the requirement to return true is it is a FP induction variable. The checks was not needed because InductionBinOp was not set on non FP cases before.
https://reviews.llvm.org/D60565 depends on the patch.
Committed on behalf of @Whitney (Whitney Tsang).
Reviewers: jdoerfert, kbarton, fhahn, hfinkel, dmgreen, Meinersbur
Reviewed By: jdoerfert
Subscribers: mgorny, hiraditya, jsji, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D61329
llvm-svn: 360671
Summary:
We hit undefined references building with ThinLTO when one source file
contained explicit instantiations of a template method (weak_odr) but
there were also implicit instantiations in another file (linkonce_odr),
and the latter was the prevailing copy. In this case the symbol was
marked hidden when the prevailing linkonce_odr copy was promoted to
weak_odr. It led to unsats when the resulting shared library was linked
with other code that contained a reference (expecting to be resolved due
to the explicit instantiation).
Add a CanAutoHide flag to the GV summary to allow the thin link to
identify when all copies are eligible for auto-hiding (because they were
all originally linkonce_odr global unnamed addr), and only do the
auto-hide in that case.
Most of the changes here are due to plumbing the new flag through the
bitcode and llvm assembly, and resulting test changes. I augmented the
existing auto-hide test to check for this situation.
Reviewers: pcc
Subscribers: mehdi_amini, inglorion, eraman, dexonsmith, arphaman, dang, llvm-commits, steven_wu, wmi
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D59709
llvm-svn: 360466
If we have a large module which is mostly intrinsics, we hammer the lib call lookup path from CodeGenPrepare. Adding a fastpath reduces compile by 15% for one such example.
The problem is really more general than intrinsics - a module with lots of non-intrinsics non-libcall calls has the same problem - but we might as well avoid an easy case quickly.
llvm-svn: 360391
InsertBinop tries to move insertion-points out of loops for expressions
that are loop-invariant. This patch adds a new parameter, IsSafeToHost,
to guard that hoisting. This allows callers to suppress that hoisting
for unsafe situations, such as divisions that may have a zero
denominator.
This fixes PR38697.
Differential Revision: https://reviews.llvm.org/D55232
llvm-svn: 360280
Summary:
Preserve MemorySSA in LoopSimplify, in the old pass manager, if the analysis is available.
Do not preserve it in the new pass manager.
Update tests.
Subscribers: nemanjai, jlebar, javed.absar, Prazek, kbarton, zzheng, jsji, llvm-commits, george.burgess.iv, chandlerc
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D60833
llvm-svn: 360270
Summary:
Currently we express umin as `~umax(~x, ~y)`. However, this becomes
a problem for operands in non-integral pointer spaces, because `~x`
is not something we can compute for `x` non-integral. However, since
comparisons are generally still allowed, we are actually able to
express `umin(x, y)` directly as long as we don't try to express is
as a umax. Support this by adding an explicit umin/smin representation
to SCEV. We do this by factoring the existing getUMax/getSMax functions
into a new function that does all four. The previous two functions were
largely identical.
Reviewed By: sanjoy
Differential Revision: https://reviews.llvm.org/D50167
llvm-svn: 360159
Summary:
Originally the insertDef method was only used when building MemorySSA, and was limiting the number of Phi nodes that it created.
Now it's used for updates as well, and it can create additional Phis needed for correctness.
Make sure no Phis are created in unreachable blocks (condition met during MSSA build), otherwise the renamePass will find a null DTNode.
Resolves PR41640.
Reviewers: george.burgess.iv
Subscribers: jlebar, Prazek, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D61410
llvm-svn: 359845
Summary: Create a method to clean up multiple potentially trivial phis, since we will need this often.
Reviewers: george.burgess.iv
Subscribers: jlebar, Prazek, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D61471
llvm-svn: 359842
Summary:
Commit
rL331949: SCEV] Do not use induction in isKnownPredicate for simplification umax
changed the codepath for umax from isKnownPredicate to
isKnownViaNonRecursiveReasoning to avoid compile time blow up (and as
I found out also stack overflows). However, there is an exact copy of
the code for umax that was lacking this change. In D50167 I want to unify
these codepaths, but to avoid that being a behavior change for the smax
case, pull this independent bit out of it.
Reviewed By: sanjoy
Differential Revision: https://reviews.llvm.org/D61166
llvm-svn: 359693
Summary:
This change was part of D46460. However, in the meantime rL341926 fixed the
correctness issue here. What remained was the performance issue in setLoopID
where it would iterate through all blocks in the loop and their successors,
rather than just the predecessor of the header (the later presumably being
much faster). We already have the `getLoopLatches` to compute precisely these
basic blocks in an efficient manner, so just use it (as the original commit
did for `getLoopID`).
Reviewed By: jdoerfert
Differential Revision: https://reviews.llvm.org/D61215
llvm-svn: 359684
Summary:
MemorySSA keeps internal pointers of AA and DT.
If these get invalidated, so should MemorySSA.
Reviewers: george.burgess.iv, chandlerc
Subscribers: jlebar, Prazek, llvm-commits
Tags: LLVM
Differential Revision: https://reviews.llvm.org/D61043
llvm-svn: 359627
Summary:
This is a redo of D60914.
The objective is to not invalidate AAManager, which is stateless, unless
there is an explicit invalidate in one of the AAResults.
To achieve this, this patch adds an API to PAC, to check precisely this:
is this analysis not invalidated explicitly == is this analysis not abandoned == is this analysis stateless, so preserved without explicitly being marked as preserved by everyone
Reviewers: chandlerc
Subscribers: mehdi_amini, jlebar, george.burgess.iv, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D61284
llvm-svn: 359622
Summary:
MemorySSA keeps internal pointers of AA and DT.
If these get invalidated, so should MemorySSA.
Reviewers: george.burgess.iv, chandlerc
Subscribers: jlebar, Prazek, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D61043
........
This was causing windows build bot failures
llvm-svn: 359555
This implements TargetTransformInfo method getMemcpyCost, which estimates the
number of instructions to which a memcpy instruction expands to.
Differential Revision: https://reviews.llvm.org/D59787
llvm-svn: 359547
Summary:
MemorySSA keeps internal pointers of AA and DT.
If these get invalidated, so should MemorySSA.
Reviewers: george.burgess.iv, chandlerc
Subscribers: jlebar, Prazek, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D61043
llvm-svn: 359519
I got confused on the terminology, and the change in D60598 was not
correct. I was thinking of "exact" in terms of the result being
non-approximate. However, the relevant distinction here is whether
the result is
* Largest range such that:
Forall Y in Other: Forall X in Result: X BinOp Y does not wrap.
(makeGuaranteedNoWrapRegion)
* Smallest range such that:
Forall Y in Other: Forall X not in Result: X BinOp Y wraps.
(A hypothetical makeAllowedNoWrapRegion)
* Both. (makeExactNoWrapRegion)
I'm adding a separate makeExactNoWrapRegion method accepting a
single APInt (same as makeExactICmpRegion) and using it in the
places where the guarantee is relevant.
Differential Revision: https://reviews.llvm.org/D60960
llvm-svn: 359402
Summary:
Both the input Value pointer and the returned Value
pointers in GetUnderlyingObjects are now declared as
const.
It turned out that all current (in-tree) uses of
GetUnderlyingObjects were trivial to update, being
satisfied with have those Value pointers declared
as const. Actually, in the past several of the users
had to use const_cast, just because of ValueTracking
not providing a version of GetUnderlyingObjects with
"const" Value pointers. With this patch we get rid
of those const casts.
Reviewers: hfinkel, materi, jkorous
Reviewed By: jkorous
Subscribers: dexonsmith, jkorous, jholewinski, sdardis, eraman, hiraditya, jrtc27, atanasyan, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D61038
llvm-svn: 359072
Summary:
If two arguments are both readonly, then they have no memory dependency
that would violate noalias, even if they do actually overlap.
Reviewers: hfinkel, efriedma
Reviewed By: efriedma
Subscribers: efriedma, hiraditya, llvm-commits, tstellar
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D60239
llvm-svn: 359047
Summary:
Enabling MemorySSA in the old pass manager leads to MemorySSA being run
twice due to the fact that LCSSA and LoopSimplify do not preserve
MemorySSA. This is the first step to address that: target LCSSA.
LCSSA does not make any changes that invalidate MemorySSA, so it
preserves it by design. It must preserve AA as well, for this to hold.
After this patch, MemorySSA is still run twice in the old pass manager.
Step two follows: target LoopSimplify.
Subscribers: mehdi_amini, jlebar, Prazek, llvm-commits, george.burgess.iv, chandlerc
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D60832
llvm-svn: 359032
Converting InlineCost interface and its internals into CallBase usage.
Inliners themselves are still not converted.
Reviewed By: reames
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D60636
llvm-svn: 358982
In the process, use the existing masked.load combine which is slightly stronger, and handles a mix of zero and undef elements in the mask.
llvm-svn: 358913
This reverts commit 7bf4d7c07f2fac862ef34c82ad0fef6513452445.
After thinking about this more, this isn't right, the range is not exact
in the same sense as makeExactICmpRegion(). This needs a separate
function.
llvm-svn: 358876
Following D60632 makeGuaranteedNoWrapRegion() always returns an
exact nowrap region. Rename the function accordingly. This is in
line with the naming of makeExactICmpRegion().
llvm-svn: 358875
ConstantRanges have an annoying special case: If upper and lower are
the same, it can be either an empty or a full set. When constructing
constant ranges nearly always a full set is intended, but this still
requires an explicit check in many places.
This revision adds a getNonEmpty() constructor that disambiguates this
case: If upper and lower are the same, a full set is created.
Differential Revision: https://reviews.llvm.org/D60947
llvm-svn: 358854
code to `CallBase`.
This patch focuses on the legacy PM, call graph, and some of inliner and legacy
passes interacting with those APIs from `CallSite` to the new `CallBase` class.
No interesting changes.
Differential Revision: https://reviews.llvm.org/D60412
llvm-svn: 358739
Summary:
The immediate post dominator of the loop header may be part of the divergent loop.
Since this /was/ the divergence propagation bound the SDA would not detect joins of divergent paths outside the loop.
Reviewers: nhaehnle
Reviewed By: nhaehnle
Subscribers: mmasten, arsenm, jvesely, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D59042
llvm-svn: 358681
isSafeToExpand was making a common, but dangerously wrong, mistake in assuming that if any instruction within a basic block executes, that all instructions within that block must execute. This can be trivially shown to be false by considering the following small example:
bb:
add x, y <-- InsertionPoint
call @throws()
udiv x, y <-- SCEV* S
br ...
It's clearly not legal to expand S above the throwing call, but the previous logic would do so since S dominates (but not properlyDominates) the block containing the InsertionPoint.
Since iterating instructions w/in a block is expensive, this change special cases two cases: 1) S is an operand of InsertionPoint, and 2) InsertionPoint is the terminator of it's block. These two together are enough to keep all current optimizations triggering while fixing the latent correctness issue.
As best I can tell, this is a silent bug in current ToT. Given that, there's no tests with this change. It was noticed in an upcoming optimization change (D60093), and was reviewed as part of that. That change will include the test which caused me to notice the issue. I'm submitting this seperately so that anyone bisecting a problem gets a clear explanation.
llvm-svn: 358680
If a branch is conditional on extractvalue(op.with.overflow(%x, C), 1)
then we can constrain the value of %x inside the branch based on
makeGuaranteedNoWrapRegion(). We do this by extending the edge-value
handling in LVI. This allows CVP to then fold comparisons against %x,
as illustrated in the tests.
Differential Revision: https://reviews.llvm.org/D60650
llvm-svn: 358597
This adds a WithOverflowInst class with a few helper methods to get
the underlying binop, signedness and nowrap type and makes use of it
where sensible. There will be two more uses in D60650/D60656.
The refactorings are all NFC, though I left some TODOs where things
could be improved. In particular we have two places where add/sub are
handled but mul isn't.
Differential Revision: https://reviews.llvm.org/D60668
llvm-svn: 358512
Summary:
When inserting a new Def, MemorySSA may be have non-minimal number of Phis.
While inserting, the walk to find the previous definition may cleanup minimal Phis.
When the last definition is trivial to obtain, we do not cache it.
It is possible while getting the previous definition for a Def to get two different answers:
- one that was straight-forward to find when walking the first path (a trivial phi in this case), and
- another that follows a cleanup of the trivial phi, it determines it may need additional Phi nodes, it inserts them and returns a new phi in the same position as the former trivial one.
While the Phis added for the second path are all redundant, they are not complete (the walk is only done upwards), and they are not properly cleaned up afterwards.
A way to fix this problem is to cache the straight-forward answer we got on the first walk.
The caching is only kept for the duration of a getPreviousDef call, and for Phis we use TrackingVH, so removing the trivial phi will lead to replacing it with the next dominating phi in the cache.
Resolves PR40749.
Reviewers: george.burgess.iv
Subscribers: jlebar, Prazek, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D60634
llvm-svn: 358313
Summary:
Create a method to forget everything in SCEV.
Add a cl::opt and PassManagerBuilder option to use this in LoopUnroll.
Motivation: Certain Halide applications spend a very long time compiling in forgetLoop, and prefer to forget everything and rebuild SCEV from scratch.
Sample difference in compile time reduction: 21.04 to 14.78 using current ToT release build.
Testcase showcasing this cannot be opensourced and is fairly large.
The option disabled by default, but it may be desirable to enable by
default. Evidence in favor (two difference runs on different days/ToT state):
File Before (s) After (s)
clang-9.bc 7267.91 6639.14
llvm-as.bc 194.12 194.12
llvm-dis.bc 62.50 62.50
opt.bc 1855.85 1857.53
File Before (s) After (s)
clang-9.bc 8588.70 7812.83
llvm-as.bc 196.20 194.78
llvm-dis.bc 61.55 61.97
opt.bc 1739.78 1886.26
Reviewers: sanjoy
Subscribers: mehdi_amini, jlebar, zzheng, javed.absar, dmgreen, jdoerfert, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D60144
llvm-svn: 358304
Summary:
After introducing the limit for clobber walking, `walkToPhiOrClobber` would assert that the limit is at least 1 on entry.
The test included triggered that assert.
The callsite in `tryOptimizePhi` making the calls to `walkToPhiOrClobber` is structured like this:
```
while (true) {
if (getBlockingAccess()) { // calls walkToPhiOrClobber
}
for (...) {
walkToPhiOrClobber();
}
}
```
The cleanest fix is to check if the limit was reached inside `walkToPhiOrClobber`, and give an allowence of 1.
This approach not make any alias() calls (no calls to instructionClobbersQuery), so the performance condition is enforced.
The limit is set back to 0 if not used, as this provides info on the fact that we stopped before reaching a true clobber.
Reviewers: george.burgess.iv
Subscribers: jlebar, Prazek, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D60479
llvm-svn: 358303
This is a follow-up patch to D60504 to further improve
performance issues in computeKnownBitsFromAssume.
The patch is NFC, but may improve compile-time performance
if the compiler isn't clever enough to do the optimization
itself.
llvm-svn: 358163
If the ObjectSizeOffsetEvaluator fails to fold the object size call, then it may
litter some unused instructions in the function. When done repeatably in
InstCombine, this results in an infinite loop. Fix this by tracking the set of
instructions that were inserted, then removing them on failure.
rdar://49172227
Differential revision: https://reviews.llvm.org/D60298
llvm-svn: 358146
This patch changes the order of pattern matching by first testing
a compare instruction's predicate, before doing the pattern
match for the whole expression tree.
Patch by Paul Walker.
Reviewed By: spatel
Differential Revision: https://reviews.llvm.org/D60504
llvm-svn: 358097
This is the same change as D60420 but for signed sub rather than
signed add: Range information is intersected into the known bits
result, allows to detect more no/always overflow conditions.
Differential Revision: https://reviews.llvm.org/D60469
llvm-svn: 358020
This is D59386 for the signed add case. The computeConstantRange()
result is now intersected into the existing known bits information,
allowing to detect additional no-overflow/always-overflow conditions
(though the latter isn't used yet).
This (finally...) covers the motivating case from D59071.
Differential Revision: https://reviews.llvm.org/D60420
llvm-svn: 358014
This patch factors out mappings of scalar maths functions to their vector
counterparts from TargetLibraryInfo.cpp to a separate VecFuncs.def file. Such
mappings are currently available for Accelerate framework, and SVML library.
This is in support of the follow-up: https://reviews.llvm.org/D59881
Patch by pjeeva01
Differential revision: https://reviews.llvm.org/D60211
llvm-svn: 358001
Switch part of the computeOverflowForSignedAdd() implementation to
use Range.isAllNegative() rather than KnownBits.isNegative() and
similar. They do the same thing, but using the ConstantRange methods
allows dropping the KnownBits variables more easily in D60420.
llvm-svn: 357969
Add support for min/max flavor selects in computeConstantRange(),
which allows us to fold comparisons of a min/max against a constant
in InstSimplify. This fixes an infinite InstCombine loop, with the
test case taken from D59378.
Relative to the previous iteration, this contains some adjustments for
AMDGPU med3 tests: The AMDGPU target runs InstSimplify prior to codegen,
which ends up constant folding some existing med3 tests after this
change. To preserve these tests a hidden -amdgpu-scalar-ir-passes option
is added, which allows disabling scalar IR passes (that use InstSimplify)
for testing purposes.
Differential Revision: https://reviews.llvm.org/D59506
llvm-svn: 357870
Current LCG doesn't check aliased functions. So if an internal function has a public alias it will not be added to CG SCC, but it is still reachable from outside through the alias.
So this patch adds aliased functions to SCC.
Differential Revision: https://reviews.llvm.org/D59898
llvm-svn: 357795
A block reachable from the entry block can't have any route to a block that's not reachable from the entry block (if it did, that route would make it reachable from the entry block). That is the intended performance optimization for isPotentiallyReachable. For the case where we ask whether an unreachable from entry block has a route to a reachable from entry block, we can't conclude one way or the other. Fix a bug where we claimed there could be no such route.
The fix in rL357425 ironically reintroduced the very bug it was fixing but only when a DominatorTree is provided. This fixes the remaining bug.
llvm-svn: 357734
Create method `optForNone()` testing for the function level equivalent of
`-O0` and refactor appropriately.
Differential revision: https://reviews.llvm.org/D59852
llvm-svn: 357638
The Emscripten OS provides a definition of __EMSCRIPTEN__, and also that it
supports iprintf optimizations.
Also define small_printf optimizations, which is a printf with float support
but not long double (which in wasm can be useful since long doubles are 128
bit and force linking of float128 emulation code). This part is based on
sunfish's https://reviews.llvm.org/D57620 (which can't land yet since
the WASI integration isn't ready yet).
Differential Revision: https://reviews.llvm.org/D60167
llvm-svn: 357552
The code was failing to actually check for the presence of the call to widenable_condition. The whole point of specifying the widenable_condition intrinsic was allowing widening transforms. A normal branch is not widenable. A normal branch leading to a deopt is not widenable (in general).
I added a test case via LoopPredication, but GuardWidening has an analogous bug. Those are the only two passes actually using this utility just yet. Noticed while working on LoopPredication for non-widenable branches; POC in D60111.
llvm-svn: 357493
Summary:
This lets us avoid e.g. checking if A >=s B in getSMaxExpr(A, B) if we've
already established that (A smax B) is the best we can do.
Fixes PR41225.
Reviewers: asbirlea
Subscribers: mcrosier, jlebar, bixia, jdoerfert, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D60010
llvm-svn: 357320
Updated to use DenseMap::insert instead of [] operator for insertion, to
avoid a crash caused by epoch checks.
This reverts commit 2b85de4383.
llvm-svn: 357257
By extending OrderedBB to allow removing and replacing cached
instructions, we can preserve OrderedBBs in DSE easily. This eliminates
one source of quadratic compile time in DSE.
Fixes PR38829.
Reviewers: rnk, efriedma, hfinkel
Reviewed By: efriedma
Differential Revision: https://reviews.llvm.org/D59789
llvm-svn: 357208
If the caller can preserve the OBB, we can avoid recomputing the order
for each getDependency call.
Reviewers: efriedma, rnk, hfinkel
Reviewed By: rnk
Differential Revision: https://reviews.llvm.org/D59788
llvm-svn: 357206
The issue here is that we actually allow CGSCC passes to mutate IR (and
therefore invalidate analyses) outside of the current SCC. At a minimum,
we need to support mutating parent and ancestor SCCs to support the
ArgumentPromotion pass which rewrites all calls to a function.
However, the analysis invalidation infrastructure is heavily based
around not needing to invalidate the same IR-unit at multiple levels.
With Loop passes for example, they don't invalidate other Loops. So we
need to customize how we handle CGSCC invalidation. Doing this without
gratuitously re-running analyses is even harder. I've avoided most of
these by using an out-of-band preserved set to accumulate the cross-SCC
invalidation, but it still isn't perfect in the case of re-visiting the
same SCC repeatedly *but* it coming off the worklist. Unclear how
important this use case really is, but I wanted to call it out.
Another wrinkle is that in order for this to successfully propagate to
function analyses, we have to make sure we have a proxy from the SCC to
the Function level. That requires pre-creating the necessary proxy.
The motivating test case now works cleanly and is added for
ArgumentPromotion.
Thanks for the review from Philip and Wei!
Differential Revision: https://reviews.llvm.org/D59869
llvm-svn: 357137
This adds ConstantRange::getFull(BitWidth) and
ConstantRange::getEmpty(BitWidth) named constructors as more readable
alternatives to the current ConstantRange(BitWidth, /* full */ false)
and similar. Additionally private getFull() and getEmpty() member
functions are added which return a full/empty range with the same bit
width -- these are commonly needed inside ConstantRange.cpp.
The IsFullSet argument in the ConstantRange(BitWidth, IsFullSet)
constructor is now mandatory for the few usages that still make use of it.
Differential Revision: https://reviews.llvm.org/D59716
llvm-svn: 356852
We're already computing the known bits of the operands here. If the
known bits of the operands can determine the sign bit of the result,
we'll already catch this in signedAddMayOverflow(). The only other
way (and as the comment already indicates) we'll get new information
from computing known bits on the whole add, is if there's an assumption
on it.
As such, we change the code to only compute known bits from assumptions,
instead of computing full known bits on the add (which would unnecessarily
recompute the known bits of the operands as well).
Differential Revision: https://reviews.llvm.org/D59473
llvm-svn: 356785
Summary:
Adding contained caching to AliasAnalysis. BasicAA is currently the only one using it.
AA changes:
- This patch is pulling the caches from BasicAAResults to AAResults, meaning the getModRefInfo call benefits from the IsCapturedCache as well when in "batch mode".
- All AAResultBase implementations add the QueryInfo member to all APIs. AAResults APIs maintain wrapper APIs such that all alias()/getModRefInfo call sites are unchanged.
- AA now provides a BatchAAResults type as a wrapper to AAResults. It keeps the AAResults instance and a QueryInfo instantiated to batch mode. It delegates all work to the AAResults instance with the batched QueryInfo. More API wrappers may be needed in BatchAAResults; only the minimum needed is currently added.
MemorySSA changes:
- All walkers are now templated on the AA used (AliasAnalysis=AAResults or BatchAAResults).
- At build time, we optimize uses; now we create a local walker (lives only as long as OptimizeUses does) using BatchAAResults.
- All Walkers have an internal AA and only use that now, never the AA in MemorySSA. The Walkers receive the AA they will use when built.
- The walker we use for queries after the build is instantiated on AliasAnalysis and is built after building MemorySSA and setting AA.
- All static methods doing walking are now templated on AliasAnalysisType if they are used both during build and after. If used only during build, the method now only takes a BatchAAResults. If used only after build, the method now takes an AliasAnalysis.
Subscribers: sanjoy, arsenm, jvesely, nhaehnle, jlebar, george.burgess.iv, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D59315
llvm-svn: 356783
Summary:
In C++, the behavior of casting a double value that is beyond the range
of a single precision floating-point to a float value is undefined. This
change replaces such a cast with APFloat::convert to convert the value,
which is consistent with how we convert a double value to a half value.
Reviewers: sanjoy
Subscribers: lebedev.ri, sanjoy, jlebar, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D59500
llvm-svn: 356781
This adds support for scalarizing these intrinsics as well the X86TargetTransformInfo support to avoid scalarizing them in the cases X86 can handle.
I've omitted handling special cases for constant masks for this first pass. Though CodeGenPrepare can constant fold the branch conditions and remove some of the control flow anyway.
Fixes PR40994 and is covers most of PR3666. Might want to implement constant masks to close that.
Differential Revision: https://reviews.llvm.org/D59180
llvm-svn: 356687
This is D59450, but for signed sub. This case is not NFC, because
the overflow logic in ConstantRange is more powerful than the existing
check. This resolves the TODO in the function.
I've added two tests to show that this indeed catches more cases than
the previous logic, but the main correctness test coverage here is in
the existing ConstantRange unit tests.
Differential Revision: https://reviews.llvm.org/D59617
llvm-svn: 356685
Summary:
This is a refactoring patch.
- Reduce the number of map searches by reusing the iterator.
- Add asserts to check that the entry is in the cache, as this is something BasicAA relies on to avoid infinite recursion.
Reviewers: chandlerc, aschwaighofer
Subscribers: sanjoy, jlebar, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D59151
llvm-svn: 356644
Code archaeology in D59315 revealed that MSSA should never be moved.
Rather than trying to check dynamically that this hasn't happened in the
verify() functions of Walkers, it's likely best to just delete its move
constructor.
Since all these verify() functions did is check that MSSA hasn't moved,
this allows us to remove these verify functions.
I can readd the verification checks if someone's super concerned about
us trying to `memcpy` MemorySSA or something somewhere, but I imagine we
have other problems if we're trying anything like that...
llvm-svn: 356641
This is a small followup to D59511. The code that was moved into
computeConstantRange() there is a bit overly conversative: If the
abs is not nsw, it does not compute any range. However, abs without
nsw still has a well-defined contiguous unsigned range from 0 to
SIGNED_MIN. This is a lot less useful than the usual 0 to SIGNED_MAX
range, but if we're already here we might as well specify it...
Differential Revision: https://reviews.llvm.org/D59563
llvm-svn: 356586
Improve computeOverflowForUnsignedAdd/Sub in ValueTracking by
intersecting the computeConstantRange() result into the ConstantRange
created from computeKnownBits(). This allows us to detect some
additional never/always overflows conditions that can't be determined
from known bits.
This revision also adds basic handling for constants to
computeConstantRange(). Non-splat vectors will be handled in a followup.
The signed case will also be handled in a followup, as it needs some
more groundwork.
Differential Revision: https://reviews.llvm.org/D59386
llvm-svn: 356489
These changes are related to PR37743 and include:
SelectionDAGBuilder::visitSelect handles the unary SelectPatternFlavor::SPF_ABS case to build ABS node.
Delete the redundant recognizer of the integer ABS pattern from the DAGCombiner.
Add promoting the integer ABS node in the LegalizeIntegerType.
Expand-based legalization of integer result for the ABS nodes.
Expand-based legalization of ABS vector operations.
Add some integer abs testcases for different typesizes for Thumb arch
Add the custom ABS expanding and change the SAD pattern recognizer for X86 arch: The i64 result of the ABS is expanded to:
tmp = (SRA, Hi, 31)
Lo = (UADDO tmp, Lo)
Hi = (XOR tmp, (ADDCARRY tmp, hi, Lo:1))
Lo = (XOR tmp, Lo)
The "detectZextAbsDiff" function is changed for the recognition of pattern with the ABS node. Given a ABS node, detect the following pattern:
(ABS (SUB (ZERO_EXTEND a), (ZERO_EXTEND b))).
Change integer abs testcases for codegen with the ABS node support for AArch64.
Indicate that the ABS is legal for the i64 type when the NEON is supported.
Change the integer abs testcases to show changing of codegen.
Add combine and legalization of ABS nodes for Thumb arch.
Extend 'matchSelectPattern' to recognize the ABS patterns with ICMP_SGE condition.
For discussion, see https://bugs.llvm.org/show_bug.cgi?id=37743
Patch by: @ikulagin (Ivan Kulagin)
Differential Revision: https://reviews.llvm.org/D49837
llvm-svn: 356468
As discussed on PR41125 and D59363, we have a mismatch between icmp eq/ne cases with an undef operand:
When the other operand is constant we fold to undef (handled in ConstantFoldCompareInstruction)
When the other operand is non-constant we fold to a bool constant based on isTrueWhenEqual (handled in SimplifyICmpInst).
Neither is really wrong, but this patch changes the logic in SimplifyICmpInst to consistently fold to undef.
The NewGVN test change is annoying (as with most heavily reduced tests) but AFAICT I have kept the purpose of the test based on rL291968.
Differential Revision: https://reviews.llvm.org/D59541
llvm-svn: 356456
Add support for min/max flavor selects in computeConstantRange(),
which allows us to fold comparisons of a min/max against a constant
in InstSimplify. This was suggested by spatel as an alternative
approach to D59378. I've also added the infinite looping test from
that revision here.
Differential Revision: https://reviews.llvm.org/D59506
llvm-svn: 356415
This is preparation for D59506. The InstructionSimplify abs handling
is moved into computeConstantRange(), which is the general place for
such calculations. This is NFC and doesn't affect the existing tests
in test/Transforms/InstSimplify/icmp-abs-nabs.ll.
Differential Revision: https://reviews.llvm.org/D59511
llvm-svn: 356409
This reinstates r347934, along with a tweak to address a problem with
PHI node ordering that that commit created (or exposed). (That commit
was reverted at r348426, due to the PHI node issue.)
Original commit message:
r320789 suppressed moving the insertion point of SCEV expressions with
dev/rem operations to the loop header in non-loop-invariant situations.
This, and similar, hoisting is also unsafe in the loop-invariant case,
since there may be a guard against a zero denominator. This is an
adjustment to the fix of r320789 to suppress the movement even in the
loop-invariant case.
This fixes PR30806.
Differential Revision: https://reviews.llvm.org/D57428
llvm-svn: 356392
This is the same change as rL356290, but for signed add. It replaces
the existing ripple logic with the overflow logic in ConstantRange.
This is NFC in that it should return NeverOverflow in exactly the
same cases as the previous implementation. However, it does make
computeOverflowForSignedAdd() more powerful by now also determining
AlwaysOverflows conditions. As none of its consumers handle this yet,
this has no impact on optimization. Making use of AlwaysOverflows
in with.overflow folding will be handled as a followup.
Differential Revision: https://reviews.llvm.org/D59450
llvm-svn: 356345
Following the suggestion in D59450, I'm moving the code for constructing
a ConstantRange from KnownBits out of ValueTracking, which also allows us
to test this code independently.
I'm adding this method to ConstantRange rather than KnownBits (which
would have been a bit nicer API wise) to avoid creating a dependency
from Support to IR, where ConstantRange lives.
Differential Revision: https://reviews.llvm.org/D59475
llvm-svn: 356339
Use the methods introduced in rL356276 to implement the
computeOverflowForUnsigned(Add|Sub) functions in ValueTracking, by
converting the KnownBits into a ConstantRange.
This is NFC: The existing KnownBits based implementation uses the same
logic as the the ConstantRange based one. This is not the case for the
signed equivalents, so I'm only changing unsigned here.
This is in preparation for D59386, which will also intersect the
computeConstantRange() result into the range determined from KnownBits.
llvm-svn: 356290
Summary:
The AliasSummary previously contained the AliaseeGUID, which was only
populated when reading the summary from bitcode. This patch changes it
to instead hold the ValueInfo of the aliasee, and always populates it.
This enables more efficient access to the ValueInfo (specifically in the
recent patch r352438 which needed to perform an index hash table lookup
using the aliasee GUID).
As noted in the comments in AliasSummary, we no longer technically need
to keep a pointer to the corresponding aliasee summary, since it could
be obtained by walking the list of summaries on the ValueInfo looking
for the summary in the same module. However, I am concerned that this
would be inefficient when walking through the index during the thin
link for various analyses. That can be reevaluated in the future.
By always populating this new field, we can remove the guard and special
handling for a 0 aliasee GUID when dumping the dot graph of the summary.
An additional improvement in this patch is when reading the summaries
from LLVM assembly we now set the AliaseeSummary field to the aliasee
summary in that same module, which makes it consistent with the behavior
when reading the summary from bitcode.
Reviewers: pcc, mehdi_amini
Subscribers: inglorion, eraman, steven_wu, dexonsmith, arphaman, llvm-commits
Differential Revision: https://reviews.llvm.org/D57470
llvm-svn: 356268
The shift argument is defined to be modulo the bitwidth, so if that argument
is a constant, we can always reduce the constant to its minimal form to allow
better CSE and other follow-on transforms.
We need to be careful to ignore constant expressions here, or we will likely
infinite loop. I'm adding a general vector constant query for that case.
Differential Revision: https://reviews.llvm.org/D59374
llvm-svn: 356192
Tim Northover