SplitEditor::defFromParent() can create a register copy.
If register is a tuple of other registers and not all lanes are used
a copy will be done on a full tuple regardless. Later register unit
for an unused lane will be considered free and another overlapping
register tuple can be assigned to a different value even though first
register is live at that point. That is because interference only look at
liveness info, while full register copy clobbers all lanes, even unused.
This patch fixes copy to only cover used lanes.
Differential Revision: https://reviews.llvm.org/D29105
llvm-svn: 293728
When choosing the best successor for a block, ordinarily we would have preferred
a block that preserves the CFG unless there is a strong probability the other
direction. For small blocks that can be duplicated we now skip that requirement
as well, subject to some simple frequency calculations.
Differential Revision: https://reviews.llvm.org/D28583
llvm-svn: 293716
Fix a bug where we would construct shufflevector instructions addressing
invalid elements.
Differential Revision: https://reviews.llvm.org/D29313
llvm-svn: 293673
Well, sort of. But the lower-level code that invoke used to be using completely
botched the handling of varargs functions, which hopefully won't be possible if
they're using the same code.
llvm-svn: 293670
Summary:
The affected transforms all implicitly use associativity of addition,
for which we usually require unsafe math to be enabled.
The "Aggressive" flag is only meant to convey information about the
performance of the fused ops relative to a fmul+fadd sequence.
Fixes Bug 31626.
Reviewers: spatel, hfinkel, mehdi_amini, arsenm, tstellarAMD
Subscribers: jholewinski, nemanjai, wdng, llvm-commits
Differential Revision: https://reviews.llvm.org/D28675
llvm-svn: 293635
Summary:
In revision rL278321, ExecutionDepsFix learned how to pick a better
register for undef register reads, e.g. for instructions such as
`vcvtsi2sdq`. While this revision improved performance on a good number
of our benchmarks, it unfortunately also caused significant regressions
(up to 3x) on others. This regression turned out to be caused by loops
such as:
PH -> A -> B (xmm<Undef> -> xmm<Def>) -> C -> D -> EXIT
^ |
+----------------------------------+
In the previous version of the clearance calculation, we would visit
the blocks in order, remembering for each whether there were any
incoming backedges from blocks that we hadn't processed yet and if
so queuing up the block to be re-processed. However, for loop structures
such as the above, this is clearly insufficient, since the block B
does not have any unknown backedges, so we do not see the false
dependency from the previous interation's Def of xmm registers in B.
To fix this, we need to consider all blocks that are part of the loop
and reprocess them one the correct clearance values are known. As
an optimization, we also want to avoid reprocessing any later blocks
that are not part of the loop.
In summary, the iteration order is as follows:
Before: PH A B C D A'
Corrected (Naive): PH A B C D A' B' C' D'
Corrected (w/ optimization): PH A B C A' B' C' D
To facilitate this optimization we introduce two new counters for each
basic block. The first counts how many of it's predecssors have
completed primary processing. The second counts how many of its
predecessors have completed all processing (we will call such a block
*done*. Now, the criteria to reprocess a block is as follows:
- All Predecessors have completed primary processing
- For x the number of predecessors that have completed primary
processing *at the time of primary processing of this block*,
the number of predecessors that are done has reached x.
The intuition behind this criterion is as follows:
We need to perform primary processing on all predecessors in order to
find out any direct defs in those predecessors. When predecessors are
done, we also know that we have information about indirect defs (e.g.
in block B though that were inherited through B->C->A->B). However,
we can't wait for all predecessors to be done, since that would
cause cyclic dependencies. However, it is guaranteed that all those
predecessors that are prior to us in reverse postorder will be done
before us. Since we iterate of the basic blocks in reverse postorder,
the number x above, is precisely the count of the number of predecessors
prior to us in reverse postorder.
Reviewers: myatsina
Differential Revision: https://reviews.llvm.org/D28759
llvm-svn: 293571
For some reason the exception selector register must be a pointer (that's
assumed by SDag); on the other hand, it gets moved into an IR-level type which
might be entirely different (i32 on AArch64). IRTranslator needs to be aware of
this.
llvm-svn: 293546
Previously, we would hit UB (or the ISD::DELETED_NODE assert) if we
happened to replace a node during UpdateChains, because it would be
left in the list we were iterating over. This nulls out the pointer
when that happens so that we can avoid the issue.
Fixes llvm.org/PR31710
llvm-svn: 293522
To simplify/clarify memory ownership, make leaks (as one was found/fixed
recently) harder to write, etc.
(also, while I was there - removed a duplicate lookup in a container)
llvm-svn: 293506
The primary use of the dump() functions in LLVM is for use in a
debugger. Unfortunately lldb does not seem to handle default arguments
so using `p SomeMI.dump()` fails and you have to type the longer `p
SomeMI.dump(nullptr)`. Remove the paramter to make the most common use
easy. (You can always construct something like `p
SomeMI.print(dbgs(),MyTII)` if you need more features).
Differential Revision: https://reviews.llvm.org/D29241
llvm-svn: 293440
The type system already requires that the number of vector elements must fit in 32-bits so an index should as well. Even if the type of the index were larger all we care about is that the constant index can fit in 64-bits so that we can call getZExtValue.
llvm-svn: 293413
When the OperandsMapper creates virtual registers, it used to just create
plain scalar register with the right size. This may confuse the
instruction selector because we lose the information of the instruction
using those registers what supposed to do. The MachineVerifier complains
about that already.
With this patch, the OperandsMapper still creates plain scalar register,
but the expectation is for the mapping function to remap the type
properly. The default mapping function has been updated to do that.
rdar://problem/30231850
llvm-svn: 293362
We had various variants of defining dump() functions in LLVM. Normalize
them (this should just consistently implement the things discussed in
http://lists.llvm.org/pipermail/cfe-dev/2014-January/034323.html
For reference:
- Public headers should just declare the dump() method but not use
LLVM_DUMP_METHOD or #if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
- The definition of a dump method should look like this:
#if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
LLVM_DUMP_METHOD void MyClass::dump() {
// print stuff to dbgs()...
}
#endif
llvm-svn: 293359
In r292621, the recommit fixes a bug related with live interval update
after the partial redundent copy is moved.
This recommit solves an additional bug related to the lack of update of
subranges.
The original patch is to solve the performance problem described in
PR27827. Register coalescing sometimes cannot remove a copy because of
interference. But if we can find a reverse copy in one of the predecessor
block of the copy, the copy is partially redundent and we may remove the
copy partially by moving it to the predecessor block without the
reverse copy.
Differential Revision: https://reviews.llvm.org/D28585
Re-apply r292621
Revert "Revert rL292621. Caused some internal build bot failures in apple."
This reverts commit r292984.
Original patch: Wei Mi <wmi@google.com>
Subrange fix: Mostly Matthias Braun <matze@braunis.de>
llvm-svn: 293353
We have to delete the block manually or it leaks. That triggers failures in
-fsanitize=leak bots (unsurprisingly), which should be fixed by this patch.
llvm-svn: 293347
Preparation for upcoming changes. No testcase as none of the public
targets bundles early enough and has a post machine scheduler enabled at
the same time. The error is also easily catched by asserts.
llvm-svn: 293324
Summary: This change prevent the signed value of cost from being negative as the value is passed as an unsigned argument.
Reviewers: mcrosier, jmolloy, qcolombet, javed.absar
Reviewed By: mcrosier, qcolombet
Subscribers: llvm-commits
Differential Revision: https://reviews.llvm.org/D28871
llvm-svn: 293307
In case of a SIGN/ZERO_EXTEND of an incomplete vector type (using only a
partial number of available vector elements), WidenVecRes_Convert() used to
resort to scalarization.
This patch adds a handling of the (common) case where an input vector can be
found of same width as the widened result vector, by converting the node to
SIGN/ZERO_EXTEND_VECTOR_INREG.
Review: Eli Friedman
llvm-svn: 293268
The translation scheme is mostly cribbed from FastISel, and it's not entirely
convincing semantically. But it does seem to work in the common cases and allow
variables to be printed so it can't be all wrong.
llvm-svn: 293228
This commit introduces a set of experimental intrinsics intended to prevent
optimizations that make assumptions about the rounding mode and floating point
exception behavior. These intrinsics will later be extended to specify
flush-to-zero behavior. More work is also required to model instruction
dependencies in machine code and to generate these instructions from clang
(when required by pragmas and/or command line options that are not currently
supported).
Differential Revision: https://reviews.llvm.org/D27028
llvm-svn: 293226
* Simplify Consecutive Merge Store Candidate Search
Now that address aliasing is much less conservative, push through
simplified store merging search and chain alias analysis which only
checks for parallel stores through the chain subgraph. This is cleaner
as the separation of non-interfering loads/stores from the
store-merging logic.
When merging stores search up the chain through a single load, and
finds all possible stores by looking down from through a load and a
TokenFactor to all stores visited.
This improves the quality of the output SelectionDAG and the output
Codegen (save perhaps for some ARM cases where we correctly constructs
wider loads, but then promotes them to float operations which appear
but requires more expensive constant generation).
Some minor peephole optimizations to deal with improved SubDAG shapes (listed below)
Additional Minor Changes:
1. Finishes removing unused AliasLoad code
2. Unifies the chain aggregation in the merged stores across code
paths
3. Re-add the Store node to the worklist after calling
SimplifyDemandedBits.
4. Increase GatherAllAliasesMaxDepth from 6 to 18. That number is
arbitrary, but seems sufficient to not cause regressions in
tests.
5. Remove Chain dependencies of Memory operations on CopyfromReg
nodes as these are captured by data dependence
6. Forward loads-store values through tokenfactors containing
{CopyToReg,CopyFromReg} Values.
7. Peephole to convert buildvector of extract_vector_elt to
extract_subvector if possible (see
CodeGen/AArch64/store-merge.ll)
8. Store merging for the ARM target is restricted to 32-bit as
some in some contexts invalid 64-bit operations are being
generated. This can be removed once appropriate checks are
added.
This finishes the change Matt Arsenault started in r246307 and
jyknight's original patch.
Many tests required some changes as memory operations are now
reorderable, improving load-store forwarding. One test in
particular is worth noting:
CodeGen/PowerPC/ppc64-align-long-double.ll - Improved load-store
forwarding converts a load-store pair into a parallel store and
a memory-realized bitcast of the same value. However, because we
lose the sharing of the explicit and implicit store values we
must create another local store. A similar transformation
happens before SelectionDAG as well.
Reviewers: arsenm, hfinkel, tstellarAMD, jyknight, nhaehnle
llvm-svn: 293184
This allows MIR passes to emit optimization remarks with the same level
of functionality that is available to IR passes.
It also hooks up the greedy register allocator to report spills. This
allows for interesting use cases like increasing interleaving on a loop
until spilling of registers is observed.
I still need to experiment whether reporting every spill scales but this
demonstrates for now that the functionality works from llc
using -pass-remarks*=<pass>.
Differential Revision: https://reviews.llvm.org/D29004
llvm-svn: 293110
Later code expects the vector loads produced to be directly
concatenable, which means we shouldn't pad anything except the last load
produced with UNDEF.
llvm-svn: 293088
The previous patch (https://reviews.llvm.org/rL289538) got reverted because of a bug. Chandler also requested some changes to the algorithm.
http://lists.llvm.org/pipermail/llvm-commits/Week-of-Mon-20161212/413479.html
This is an updated patch. The key difference is that collectBitProviders (renamed to calculateByteProvider) now collects the origin of one byte, not the whole value. It simplifies the implementation and allows to stop the traversal earlier if we know that the result won't be used.
From the original commit:
Match a pattern where a wide type scalar value is loaded by several narrow loads and combined by shifts and ors. Fold it into a single load or a load and a bswap if the targets supports it.
Assuming little endian target:
i8 *a = ...
i32 val = a[0] | (a[1] << 8) | (a[2] << 16) | (a[3] << 24)
=>
i32 val = *((i32)a)
i8 *a = ...
i32 val = (a[0] << 24) | (a[1] << 16) | (a[2] << 8) | a[3]
=>
i32 val = BSWAP(*((i32)a))
This optimization was discussed on llvm-dev some time ago in "Load combine pass" thread. We came to the conclusion that we want to do this transformation late in the pipeline because in presence of atomic loads load widening is irreversible transformation and it might hinder other optimizations.
Eventually we'd like to support folding patterns like this where the offset has a variable and a constant part:
i32 val = a[i] | (a[i + 1] << 8) | (a[i + 2] << 16) | (a[i + 3] << 24)
Matching the pattern above is easier at SelectionDAG level since address reassociation has already happened and the fact that the loads are adjacent is clear. Understanding that these loads are adjacent at IR level would have involved looking through geps/zexts/adds while looking at the addresses.
The general scheme is to match OR expressions by recursively calculating the origin of individual bytes which constitute the resulting OR value. If all the OR bytes come from memory verify that they are adjacent and match with little or big endian encoding of a wider value. If so and the load of the wider type (and bswap if needed) is allowed by the target generate a load and a bswap if needed.
Reviewed By: RKSimon, filcab, chandlerc
Differential Revision: https://reviews.llvm.org/D27861
llvm-svn: 293036
If dominator tree has no roots, the pass that calculates it is
likely to be skipped. It occures, for instance, in the case of
entities with linkage available_externally. Do not run tree
verification in such case.
Differential Revision: https://reviews.llvm.org/D28767
llvm-svn: 293033
clang already emits this with -cl-no-signed-zeros, but codegen
doesn't do anything with it. Treat it like the other fast math
attributes, and change one place to use it.
llvm-svn: 293024
Looks like our cmake goop for handling .inc->td dependencies doesn't
track the .td files.
This manifests as cmake complaining about missing files since r293009.
Force a rerun to avoid that.
llvm-svn: 293012
There was a bug here where we were using p0 instead of s32 for the
selector type in the landingpad. Instead of hardcoding these types we
should get the types from the landingpad instruction directly.
Note that we replicate an assert from SDAG here to only support
two-valued landingpads.
llvm-svn: 292995
Summary:
When conditional branches with complex conditions are split into
multiple branches in SelectionDAGBuilder::FindMergedConditions, also
handle inverted conditions. These may sometimes appear without having
been optimized by InstCombine when CodeGenPrepare decides to sink and
duplicate cmp instructions, causing them to have only one use. This
problem can be increased by e.g. GVNHoist hiding more cmps from
InstCombine by combining equivalent cmps from different blocks.
For example codegen X & !(Y | Z) as:
jmp_if_X TmpBB
jmp FBB
TmpBB:
jmp_if_notY Tmp2BB
jmp FBB
Tmp2BB:
jmp_if_notZ TBB
jmp FBB
Reviewers: bogner, MatzeB, qcolombet
Subscribers: llvm-commits, hiraditya, mcrosier, sebpop
Differential Revision: https://reviews.llvm.org/D28380
llvm-svn: 292944
Summary:
This teaches getNode to simplify extracting from Undef. This is similar to what is done for EXTRACT_VECTOR_ELT. It also adds support for extracting from CONCAT_VECTOR when we can reuse one of the inputs to the concat. These seem like simple non-target specific optimizations.
For X86 we currently handle undef in extractSubvector, but not all EXTRACT_SUBVECTOR creations go through there.
Ultimately, my motivation here is to simplify extractSubvector and remove custom lowering for EXTRACT_SUBVECTOR since we don't do anything but handle undef and BUILD_VECTOR optimizations, but those should be DAG combines.
Reviewers: RKSimon, delena
Reviewed By: RKSimon
Subscribers: llvm-commits
Differential Revision: https://reviews.llvm.org/D29000
llvm-svn: 292876
A register unit may be allocatable and non-reserved but some of the
register(tuples) built with it are reserved. We still need to calculate
liveness in this case.
Note to out of tree targets: If you start seeing machine verifier errors
with this commit, it probably means that you do not properly mark super
registers of reserved register as reserved. See for example r292836 or
r292870 for example on how to fix that.
rdar://29996737
Differential Revision: https://reviews.llvm.org/D28881
llvm-svn: 292871
Summary:
The LibFunc::Func enum holds enumerators named for libc functions.
Unfortunately, there are real situations, including libc implementations, where
function names are actually macros (musl uses "#define fopen64 fopen", for
example; any other transitively visible macro would have similar effects).
Strictly speaking, a conforming C++ Standard Library should provide any such
macros as functions instead (via <cstdio>). However, there are some "library"
functions which are not part of the standard, and thus not subject to this
rule (fopen64, for example). So, in order to be both portable and consistent,
the enum should not use the bare function names.
The old enum naming used a namespace LibFunc and an enum Func, with bare
enumerators. This patch changes LibFunc to be an enum with enumerators prefixed
with "LibFFunc_". (Unfortunately, a scoped enum is not sufficient to override
macros.)
There are additional changes required in clang.
Reviewers: rsmith
Subscribers: mehdi_amini, mzolotukhin, nemanjai, llvm-commits
Differential Revision: https://reviews.llvm.org/D28476
llvm-svn: 292848
Since we're now avoiding operations using narrow scalar integer types,
we have to legalize the integer side of the FP conversions.
This requires teaching the legalizer how to do that.
llvm-svn: 292828
Re-Commit r292543 with a fix for the situation when the chain end is
MBB.end().
This function can be used to accumulate the set of all read and modified
register in a sequence of instructions.
Use this code in AArch64A57FPLoadBalancing::scavengeRegister() to prove
the concept.
- The AArch64A57LoadBalancing code is using a backwards analysis now
which is irrespective of kill flags. This is the main motivation for
this change.
Differential Revision: http://reviews.llvm.org/D22082
llvm-svn: 292705
Translating the constant can create more VRegs, which can invalidate the
reference into the DenseMap. So we have to look up the value again after all
that's happened.
llvm-svn: 292675
This patch fixes debug information for __thread variable on Mips
using .dtprelword and .dtpreldword directives.
Patch by Aleksandar Beserminji.
Differential Revision: http://reviews.llvm.org/D28770
llvm-svn: 292624
The recommit fixes a bug related with live interval update after the partial
redundent copy is moved.
The original patch is to solve the performance problem described in PR27827.
Register coalescing sometimes cannot remove a copy because of interference.
But if we can find a reverse copy in one of the predecessor block of the copy,
the copy is partially redundent and we may remove the copy partially by moving
it to the predecessor block without the reverse copy.
Differential Revision: https://reviews.llvm.org/D28585
llvm-svn: 292621
Inline spiller can decide to move a spill as early as possible in the basic block.
It will skip phis and label, but we also need to make sure it skips instructions
in the basic block prologue which restore exec mask.
Added isPositionLike callback in TargetInstrInfo to detect instructions which
shall be skipped in addition to common phis, labels etc.
Differential Revision: https://reviews.llvm.org/D27997
llvm-svn: 292554
It's easier to test the non-fallback path if we just drop these
intrinsics for now, like we did before we added the fallback path.
We'll obviously need to fix this properly, but the fixme for that is
already here.
llvm-svn: 292547
Rather than trying to find MF based on the possibly-null MI we've
passed in here, just pass it in directly. It's already available at
all callers anyway.
llvm-svn: 292544
This function can be used to accumulate the set of all read and modified
register in a sequence of instructions.
Use this code in AArch64A57FPLoadBalancing::scavengeRegister() to prove
the concept.
- The AArch64A57LoadBalancing code is using a backwards analysis now
which is irrespective of kill flags. This is the main motivation for
this change.
Differential Revision: http://reviews.llvm.org/D22082
llvm-svn: 292543
This is a set of register units intended to track register liveness, it
is similar in spirit to LivePhysRegs.
You can also think of this as the liveness tracking parts of the
RegisterScavenger factored out into an own class.
This was proposed in http://llvm.org/PR27609
Differential Revision: http://reviews.llvm.org/D21916
llvm-svn: 292542
This patch improves the knownbits logic for unsigned integer min/max opcodes.
For UMIN we know that the result will have the maximum of the inputs' known leading zero bits in the result, similarly for UMAX the maximum of the inputs' leading one bits.
This is particularly useful for simplifying clamping patterns,. e.g. as SSE doesn't have a uitofp instruction we want to use sitofp instead where possible and for that we need to confirm that the top bit is not set.
Differential Revision: https://reviews.llvm.org/D28853
llvm-svn: 292528
Summary:
The SDNodeOrder is saved in the IROrder field in the SDNode, and this
field may affects scheduling. Thus, letting dbg.value/declare increase
the order numbers may in turn affect scheduling.
Because of this change we also need to update the code deciding when
dbg values should be output, in ScheduleDAGSDNodes.cpp/ProcessSDDbgValues.
Dbg values now have the same order as the SDNode they are connected to,
not the following orders.
Test cases provided by Florian Hahn.
Reviewers: bogner, aprantl, sunfish, atrick
Reviewed By: atrick
Subscribers: fhahn, probinson, andreadb, llvm-commits, MatzeB
Differential Revision: https://reviews.llvm.org/D25318
llvm-svn: 292485
Summary:
Adds a RegisterBank tablegen class that can be used to declare the register
banks and an associated tablegen pass to generate the necessary code.
Changes since first commit attempt:
* Added missing guards
* Added more missing guards
* Found and fixed a use-after-free bug involving Twine locals
Reviewers: t.p.northover, ab, rovka, qcolombet
Reviewed By: qcolombet
Subscribers: aditya_nandakumar, rengolin, kristof.beyls, vkalintiris, mgorny, dberris, llvm-commits, rovka
Differential Revision: https://reviews.llvm.org/D27338
llvm-svn: 292478
- Fix doxygen comments: Do not repeat name, remove duplicated doxygen
comment (on declaration + implementation), etc.
- Use more range based for
llvm-svn: 292455
Non-prevailing weak/linkonce odr symbols will be dropped by ThinLTO to
available_externally when possible. If they had an initializer in the
global_ctors list, a comdat group was being created. This code
already had logic to skip available_externally defs, but now the
EliminateAvailableExternally pass will drop these symbols to
declarations earlier. Change the check to skip all declarations for
linker (which includes available_externally along with declarations).
Reviewers: mehdi_amini
Subscribers: llvm-commits
Differential Revision: https://reviews.llvm.org/D28737
llvm-svn: 292408
Summary:
In this function, virtual registers can be introduced (for example
through calls to emitThumbRegPlusImmInReg). doScavengeFrameVirtualRegs
will replace those virtual registers with concrete registers later on
in PrologEpilogInserter, which sets NoVRegs again.
This patch fixes the Codegen/Thumb/segmented-stacks.ll test case which
failed with expensive checks.
https://llvm.org/bugs/show_bug.cgi?id=27484
Reviewers: rnk, bkramer, olista01
Reviewed By: olista01
Subscribers: llvm-commits, rengolin
Differential Revision: https://reviews.llvm.org/D28829
llvm-svn: 292372
Summary:
Adds a RegisterBank tablegen class that can be used to declare the register
banks and an associated tablegen pass to generate the necessary code.
Changes since last commit:
The new tablegen pass is now correctly guarded by LLVM_BUILD_GLOBAL_ISEL and
this should fix the buildbots however it may not be the whole fix. The previous
buildbot failures suggest there may be a memory bug lurking that I'm unable to
reproduce (including when using asan) or spot in the source. If they re-occur
on this commit then I'll need assistance from the bot owners to track it down.
Reviewers: t.p.northover, ab, rovka, qcolombet
Reviewed By: qcolombet
Subscribers: aditya_nandakumar, rengolin, kristof.beyls, vkalintiris, mgorny, dberris, llvm-commits, rovka
Differential Revision: https://reviews.llvm.org/D27338
llvm-svn: 292367
You can now define the register class of a virtual register on the
operand itself avoiding the need to use a "registers:" block.
Example: "%0:gr64 = COPY %rax"
Differential Revision: https://reviews.llvm.org/D22398
llvm-svn: 292321
The patch is to solve the performance problem described in PR27827.
Register coalescing sometimes cannot remove a copy because of interference.
But if we can find a reverse copy in one of the predecessor block of the copy,
the copy is partially redundent and we may remove the copy partially by moving
it to the predecessor block without the reverse copy.
Differential Revision: https://reviews.llvm.org/D28585
llvm-svn: 292292
Stanislav Mekhanoshin