As part of PR22777, fix testcases that fail the debug info verifier.
The changes fall into the following categories:
- Empty `filename:` fields in `MDFile`s. Compile units and some types
require non-empty filenames. A number of testcases have empty
filenames, probably due to hand-reduction of testcases.
- Not-quite empty arrays: `!{i32 0}`. This used to be equivalent in
the debug info schema to `!{}`. They cause problems for
`!MDSubroutineType`'s `types:` array, since it requires all operands
to be valid types. (Note that `!{null}` is the correct type array
for functions that take no arguments and return `void`.)
- Significantly bitrotted testcases. Nodes got left behind a few
upgrades ago because of missing or invalid tags.
llvm-svn: 232415
The problem here is the infamous one direction known safe. I was
hesitant to turn it off before b/c of the potential for regressions
without an actual bug from users hitting the problem. This is that bug ;
).
The main performance impact of having known safe in both directions is
that often times it is very difficult to find two releases without a use
in-between them since we are so conservative with determining potential
uses. The one direction known safe gets around that problem by taking
advantage of many situations where we have two retains in a row,
allowing us to avoid that problem. That being said, the one direction
known safe is unsafe. Consider the following situation:
retain(x)
retain(x)
call(x)
call(x)
release(x)
Then we know the following about the reference count of x:
// rc(x) == N (for some N).
retain(x)
// rc(x) == N+1
retain(x)
// rc(x) == N+2
call A(x)
call B(x)
// rc(x) >= 1 (since we can not release a deallocated pointer).
release(x)
// rc(x) >= 0
That is all the information that we can know statically. That means that
we know that A(x), B(x) together can release (x) at most N+1 times. Lets
say that we remove the inner retain, release pair.
// rc(x) == N (for some N).
retain(x)
// rc(x) == N+1
call A(x)
call B(x)
// rc(x) >= 1
release(x)
// rc(x) >= 0
We knew before that A(x), B(x) could release x up to N+1 times meaning
that rc(x) may be zero at the release(x). That is not safe. On the other
hand, consider the following situation where we have a must use of
release(x) that x must be kept alive for after the release(x)**. Then we
know that:
// rc(x) == N (for some N).
retain(x)
// rc(x) == N+1
retain(x)
// rc(x) == N+2
call A(x)
call B(x)
// rc(x) >= 2 (since we know that we are going to release x and that that release can not be the last use of x).
release(x)
// rc(x) >= 1 (since we can not deallocate the pointer since we have a must use after x).
…
// rc(x) >= 1
use(x)
Thus we know that statically the calls to A(x), B(x) can together only
release rc(x) N times. Thus if we remove the inner retain, release pair:
// rc(x) == N (for some N).
retain(x)
// rc(x) == N+1
call A(x)
call B(x)
// rc(x) >= 1
…
// rc(x) >= 1
use(x)
We are still safe unless in the final … there are unbalanced retains,
releases which would have caused the program to blow up anyways even
before optimization occurred. The simplest form of must use is an
additional release that has not been paired up with any retain (if we
had paired the release with a retain and removed it we would not have
the additional use). This fits nicely into the ARC framework since
basically what you do is say that given any nested releases regardless
of what is in between, the inner release is known safe. This enables us to get
back the lost performance.
<rdar://problem/19023795>
llvm-svn: 232351
Verify that debug info intrinsic arguments are valid. (These checks
will not recurse through the full debug info graph, so they don't need
to be cordoned of in `DebugInfoVerifier`.)
With those checks in place, changing the `DbgIntrinsicInst` accessors to
downcast to `MDLocalVariable` and `MDExpression` is natural (added isa
specializations in `Metadata.h` to support this).
Added tests to `test/Verifier` for the new -verify checks, and fixed the
debug info in all the in-tree tests.
If you have out-of-tree testcases that have started to fail to -verify,
hopefully the verify checks are helpful. The most likely problem is
that the expression argument is `!{}` (instead of `!MDExpression()`).
llvm-svn: 232296
Summary: This is a first step toward getting proper support for aggregate loads and stores.
Test Plan: Added unittests
Reviewers: reames, chandlerc
Reviewed By: chandlerc
Subscribers: majnemer, joker.eph, chandlerc, llvm-commits
Differential Revision: http://reviews.llvm.org/D7780
Patch by Amaury Sechet
From: Mehdi Amini <mehdi.amini@apple.com>
llvm-svn: 232284
The linker on that platform may re-order symbols or strip dead symbols, which
will break bit set checks. Avoid this by hiding the symbols from the linker.
llvm-svn: 232235
This reapplies the patch previously committed at revision 232190. This was
reverted at revision 232196 as it caused test failures in tests that did not
expect operands to be commuted. I have made the tests more resilient to
reassociation in revision 232206.
llvm-svn: 232209
As a follow-up to r232200, add an `-instcombine` to canonicalize scalar
allocations to `i32 1`. Since r232200, `iX 1` (for X != 32) are only
created by RAUWs, so this shouldn't fire too often. Nevertheless, it's
a cheap check and a nice cleanup.
llvm-svn: 232202
Write the `alloca` array size explicitly when it's non-canonical.
Previously, if the array size was `iX 1` (where X is not 32), the type
would mutate to `i32` when round-tripping through assembly.
The testcase I added fails in `verify-uselistorder` (as well as
`FileCheck`), since the use-lists for `i32 1` and `i64 1` change.
(Manman Ren came across this when running `verify-uselistorder` on some
non-trivial, optimized code as part of PR5680.)
The type mutation started with r104911, which allowed array sizes to be
something other than an `i32`. Starting with r204945, we
"canonicalized" to `i64` on 64-bit platforms -- and then on every
round-trip through assembly, mutated back to `i32`.
I bundled a fixup for `-instcombine` to avoid r204945 on scalar
allocations. (There wasn't a clean way to sequence this into two
commits, since the assembly change on its own caused testcase churn, and
the `-instcombine` change can't be tested without the assembly changes.)
An obvious alternative fix -- change `AllocaInst::AllocaInst()`,
`AsmWriter` and `LLParser` to treat `intptr_t` as the canonical type for
scalar allocations -- was rejected out of hand, since this required
teaching them each about the data layout.
A follow-up commit will add an `-instcombine` to canonicalize the scalar
allocation array size to `i32 1` rather than leaving `iX 1` alone.
rdar://problem/20075773
llvm-svn: 232200
This patch adds initial support for vector instructions to the reassociation
pass. It enables most parts of the pass to work with vectors but to keep the
size of the patch small, optimization of Xor trees, canonicalization of
negative constants and converting shifts to muls, etc., have been left out.
This will be handled in later patches.
The patch is based on an initial patch by Chad Rosier.
Differential Revision: http://reviews.llvm.org/D7566
llvm-svn: 232190
Similar to gep (r230786) and load (r230794) changes.
Similar migration script can be used to update test cases, which
successfully migrated all of LLVM and Polly, but about 4 test cases
needed manually changes in Clang.
(this script will read the contents of stdin and massage it into stdout
- wrap it in the 'apply.sh' script shown in previous commits + xargs to
apply it over a large set of test cases)
import fileinput
import sys
import re
rep = re.compile(r"(getelementptr(?:\s+inbounds)?\s*\()((<\d*\s+x\s+)?([^@]*?)(|\s*addrspace\(\d+\))\s*\*(?(3)>)\s*)(?=$|%|@|null|undef|blockaddress|getelementptr|addrspacecast|bitcast|inttoptr|zeroinitializer|<|\[\[[a-zA-Z]|\{\{)", re.MULTILINE | re.DOTALL)
def conv(match):
line = match.group(1)
line += match.group(4)
line += ", "
line += match.group(2)
return line
line = sys.stdin.read()
off = 0
for match in re.finditer(rep, line):
sys.stdout.write(line[off:match.start()])
sys.stdout.write(conv(match))
off = match.end()
sys.stdout.write(line[off:])
llvm-svn: 232184
Constant folding for shift IR instructions ignores all bits above 32 of
second argument (shift amount).
Because of that, some undef results are not recognized and APInt can
raise an assert failure if second argument has more than 64 bits.
Patch by Paweł Bylica!
Differential Revision: http://reviews.llvm.org/D7701
llvm-svn: 232176
It's firstly committed at r231630, and reverted at r231635.
Function pass InstructionSimplifier is inserted as barrier to
make sure loop unroll pass won't affect on LICM pass.
llvm-svn: 232011
The CallGraphNode function "addCalledFunction()" asserts that edges are not to intrinsics.
This patch makes sure that the Inliner does not add such an edge to the callgraph.
Fix for clang crash by assertion: https://llvm.org/bugs/show_bug.cgi?id=22857
Differential Revision: http://reviews.llvm.org/D8231
llvm-svn: 231927
Given that large parts of inst combine is restricted to instructions which have one use, getting rid of a use on the condition can help the effectiveness of the optimizer. Also, it allows the condition to potentially be deleted by instcombine rather than waiting for another pass.
I noticed this completely by accident in another test case. It's not anything that actually came from a real workload.
p.s. We should probably do the same thing for switch instructions.
Differential Revision: http://reviews.llvm.org/D8220
llvm-svn: 231881
This patch adds limited support in ValueTracking for inferring known bits of a value from conditional expressions which must be true to reach the instruction we're trying to optimize. At this time, the feature is off by default. Once landed, I'm hoping for feedback from others on both profitability and compile time impact.
Forms of conditional value propagation have been tried in LLVM before and have failed due to compile time problems. In an attempt to side step that, this patch only considers conditions where the edge leaving the branch dominates the context instruction. It does not attempt full dataflow. Even with that restriction, it handles many interesting cases:
* Early exits from functions
* Early exits from loops (for context instructions in the loop and after the check)
* Conditions which control entry into loops, including multi-version loops (such as those produced during vectorization, IRCE, loop unswitch, etc..)
Possible applications include optimizing using information provided by constructs such as: preconditions, assumptions, null checks, & range checks.
This patch implements two approaches to the problem that need further benchmarking. Approach 1 is to directly walk the dominator tree looking for interesting conditions. Approach 2 is to inspect other uses of the value being queried for interesting comparisons. From initial benchmarking, it appears that Approach 2 is faster than Approach 1, but this needs to be further validated.
Differential Revision: http://reviews.llvm.org/D7708
llvm-svn: 231879
ReplaceInstUsesWith needs to return nullptr when the input has no users,
because in that case it does not mutate the program. Otherwise, we can
get stuck in an infinite loop of repeatedly attempting to constant fold
and instruction with no users.
llvm-svn: 231755
For inner one of nested loops, it is more likely to be a hot loop,
and the runtime check can be promoted out from patch 0001, so the
overhead is less, we can try a doubled threshold to unroll more loops.
llvm-svn: 231632
Runtime unrolling is an expensive optimization which can bring benefit
only if the loop is hot and iteration number is relatively large enough.
For some loops, we know they are not worth to be runtime unrolled.
The scalar loop from vectorization is one of the cases.
llvm-svn: 231631
Runtime unrollng will introduce a runtime check in loop prologue.
If the unrolled loop is a inner loop, then the proglogue will be inside
the outer loop. LICM pass can help to promote the runtime check out if
the checked value is loop invariant.
llvm-svn: 231630
Summary:
See the two test cases.
; Can fold fcmp with undef on one side by choosing NaN for the undef
; Can fold fcmp with undef on both side
; fcmp u_pred undef, undef -> true
; fcmp o_pred undef, undef -> false
; because whatever you choose for the first undef
; you can choose NaN for the other undef
Reviewers: hfinkel, chandlerc, majnemer
Reviewed By: majnemer
Subscribers: majnemer, llvm-commits
Differential Revision: http://reviews.llvm.org/D7617
From: Mehdi Amini <mehdi.amini@apple.com>
llvm-svn: 231626
This pass interchanges loops to provide a more cache-friendly memory access.
For e.g. given a loop like -
for(int i=0;i<N;i++)
for(int j=0;j<N;j++)
A[j][i] = A[j][i]+B[j][i];
is interchanged to -
for(int j=0;j<N;j++)
for(int i=0;i<N;i++)
A[j][i] = A[j][i]+B[j][i];
This pass is currently disabled by default.
To give a brief introduction it consists of 3 stages-
LoopInterchangeLegality : Checks the legality of loop interchange based on Dependency matrix.
LoopInterchangeProfitability: A very basic heuristic has been added to check for profitibility. This will evolve over time.
LoopInterchangeTransform : Which does the actual transform.
LNT Performance tests shows improvement in Polybench/linear-algebra/kernels/mvt and Polybench/linear-algebra/kernels/gemver becnmarks.
TODO:
1) Add support for reductions and lcssa phi.
2) Improve profitability model.
3) Improve loop selection algorithm to select best loop for interchange. Currently the innermost loop is selected for interchange.
4) Improve compile time regression found in llvm lnt due to this pass.
5) Fix issues in Dependency Analysis module.
A special thanks to Hal for reviewing this code.
Review: http://reviews.llvm.org/D7499
llvm-svn: 231458
At this point, we should have decent coverage of the involved code. I've got a few more test cases to cleanup and submit, but what's here is already reasonable.
I've got a collection of liveness tests which will be posted for review along with a decent liveness algorithm in the next few days. Once those are in, the code in this file should be well tested and I can start renaming things without risk of serious breakage.
llvm-svn: 231414
isNormalFp and isFiniteNonZeroFp should not assume vector operands can not be constant expressions.
Patch by Pawel Jurek <pawel.jurek@intel.com>
Differential Revision: http://reviews.llvm.org/D8053
llvm-svn: 231359
Summary:
DataLayout keeps the string used for its creation.
As a side effect it is no longer needed in the Module.
This is "almost" NFC, the string is no longer
canonicalized, you can't rely on two "equals" DataLayout
having the same string returned by getStringRepresentation().
Get rid of DataLayoutPass: the DataLayout is in the Module
The DataLayout is "per-module", let's enforce this by not
duplicating it more than necessary.
One more step toward non-optionality of the DataLayout in the
module.
Make DataLayout Non-Optional in the Module
Module->getDataLayout() will never returns nullptr anymore.
Reviewers: echristo
Subscribers: resistor, llvm-commits, jholewinski
Differential Revision: http://reviews.llvm.org/D7992
From: Mehdi Amini <mehdi.amini@apple.com>
llvm-svn: 231270
RewriteStatepointsForGC pass emits an alloca for each GC pointer which will be relocated. It then inserts stores after def and all relocations, and inserts loads before each use as well. In the end, mem2reg is used to update IR with relocations in SSA form.
However, there is a problem with inserting stores for values defined by invoke instructions. The code didn't expect a def was a terminator instruction, and inserting instructions after these terminators resulted in malformed IR.
This patch fixes this problem by handling invoke instructions as a special case. If the def is an invoke instruction, the store will be inserted at the beginning of the normal destination block. Since return value from invoke instruction does not dominate the unwind destination block, no action is needed there.
Patch by: Chen Li
Differential Revision: http://reviews.llvm.org/D7923
llvm-svn: 231183
Selection conditions may be vectors or scalars. Make sure InstCombine
doesn't indiscriminately assume that a select which is value dependent
on another select have identical select condition types.
This fixes PR22773.
llvm-svn: 231156
Move the specialized metadata nodes for the new debug info hierarchy
into place, finishing off PR22464. I've done bootstraps (and all that)
and I'm confident this commit is NFC as far as DWARF output is
concerned. Let me know if I'm wrong :).
The code changes are fairly mechanical:
- Bumped the "Debug Info Version".
- `DIBuilder` now creates the appropriate subclass of `MDNode`.
- Subclasses of DIDescriptor now expect to hold their "MD"
counterparts (e.g., `DIBasicType` expects `MDBasicType`).
- Deleted a ton of dead code in `AsmWriter.cpp` and `DebugInfo.cpp`
for printing comments.
- Big update to LangRef to describe the nodes in the new hierarchy.
Feel free to make it better.
Testcase changes are enormous. There's an accompanying clang commit on
its way.
If you have out-of-tree debug info testcases, I just broke your build.
- `upgrade-specialized-nodes.sh` is attached to PR22564. I used it to
update all the IR testcases.
- Unfortunately I failed to find way to script the updates to CHECK
lines, so I updated all of these by hand. This was fairly painful,
since the old CHECKs are difficult to reason about. That's one of
the benefits of the new hierarchy.
This work isn't quite finished, BTW. The `DIDescriptor` subclasses are
almost empty wrappers, but not quite: they still have loose casting
checks (see the `RETURN_FROM_RAW()` macro). Once they're completely
gutted, I'll rename the "MD" classes to "DI" and kill the wrappers. I
also expect to make a few schema changes now that it's easier to reason
about everything.
llvm-svn: 231082
By loading from indexed offsets into a byte array and applying a mask, a
program can test bits from the bit set with a relatively short instruction
sequence. For example, suppose we have 15 bit sets to lay out:
A (16 bits), B (15 bits), C (14 bits), D (13 bits), E (12 bits),
F (11 bits), G (10 bits), H (9 bits), I (7 bits), J (6 bits), K (5 bits),
L (4 bits), M (3 bits), N (2 bits), O (1 bit)
These bits can be laid out in a 16-byte array like this:
Byte Offset
0123456789ABCDEF
Bit
7 HHHHHHHHHIIIIIII
6 GGGGGGGGGGJJJJJJ
5 FFFFFFFFFFFKKKKK
4 EEEEEEEEEEEELLLL
3 DDDDDDDDDDDDDMMM
2 CCCCCCCCCCCCCCNN
1 BBBBBBBBBBBBBBBO
0 AAAAAAAAAAAAAAAA
For example, to test bit X of A, we evaluate ((bits[X] & 1) != 0), or to
test bit X of I, we evaluate ((bits[9 + X] & 0x80) != 0). This can be done
in 1-2 machine instructions on x86, or 4-6 instructions on ARM.
This uses the LPT multiprocessor scheduling algorithm to lay out the bits
efficiently.
Saves ~450KB of instructions in a recent build of Chromium.
Differential Revision: http://reviews.llvm.org/D7954
llvm-svn: 231043
There's really no reason to have them have entries in the symbol table
anymore. Old versions of ld64 had some bugs in this area but those have
been fixed long ago.
llvm-svn: 231041
This re-lands change r230921. r230921 was reverted because it broke a
clang test; a checkin fixing the clang test will be commited shortly.
Summary:
As far as I can tell, the real bug causing the issue was fixed in
r230533. SCEVExpander should mark an increment operation as nuw or nsw
only if it can *prove* that the operation does not overflow. There
shouldn't be any situation where we have to do something different
because of no-wrap flags generated by SCEVExpander.
Revert "IndVarSimplify: Allow LFTR to fire more often"
This reverts commit 1ade0f0faa98877b688e0b9da58e876052c1e04e (SVN: 222213).
Revert "IndVarSimplify: Don't let LFTR compare against a poison value"
This reverts commit c0f2b8b528d8a37b0a1522aae90af649d6357eb5 (SVN: 217102).
Reviewers: majnemer, atrick, spatel
Differential Revision: http://reviews.llvm.org/D7979
llvm-svn: 231018
Summary:
As far as I can tell, the real bug causing the issue was fixed in
r230533. SCEVExpander should mark an increment operation as nuw or nsw
only if it can *prove* that the operation does not overflow. There
shouldn't be any situation where we have to do something different
because of no-wrap flags generated by SCEVExpander.
Revert "IndVarSimplify: Allow LFTR to fire more often"
This reverts commit 1ade0f0faa98877b688e0b9da58e876052c1e04e (SVN: 222213).
Revert "IndVarSimplify: Don't let LFTR compare against a poison value"
This reverts commit c0f2b8b528d8a37b0a1522aae90af649d6357eb5 (SVN: 217102).
Reviewers: majnemer, atrick, spatel
Differential Revision: http://reviews.llvm.org/D7979
llvm-svn: 230921
r228631 stopped using `DW_OP_piece` inside `DIExpression`s in the IR,
but it apparently missed updating these testcases. Caught by verifier
checks for `MDExpression` while working on moving the new hierarchy into
place.
llvm-svn: 230882
Leaving empty blocks around just opens up a can of bugs like PR22704. Deleting
them early also slightly simplifies code.
Thanks to Sanjay for the IR test case.
llvm-svn: 230856
It turns out the naming of inserted phis and selects is sensative to the order in which two sets are iterated. We need to nail this down to avoid non-deterministic output and possible test failures.
The modified test is the one I first noticed something odd in. The change is making it more strict to report the error. With the test change, but without the code change, the test fails roughly 1 in 5. With the code change, I've run ~30 runs without error.
Long term, the right fix here is to adjust the naming scheme. I'm checking in this hack to avoid any possible non-determinism in the tests over the weekend. HJust because I only noticed one case doesn't mean it's actually the only case. I hope to get to the right change Monday.
std->llvm data structure changes bugfix change #3
llvm-svn: 230835
These tests cover the 'base object' identification and rewritting portion of RewriteStatepointsForGC. These aren't completely exhaustive, but they've proven to be reasonable effective over time at finding regressions.
In the process of porting these tests over, I found my first "cleanup per llvm code style standards" bug. We were relying on the order of iteration when testing the base pointers found for a derived pointer. When we switched from std::set to DenseSet, this stopped being a safe assumption. I'm suspecting I'm going to find more of those. In particular, I'm now really wondering about the main iteration loop for this algorithm. I need to go take a closer look at the assumptions there.
I'm not really happy with the fact these are testing what is essentially debug output (i.e. enabled via command line flags). Suggestions for how to structure this better are very welcome.
llvm-svn: 230818
Essentially the same as the GEP change in r230786.
A similar migration script can be used to update test cases, though a few more
test case improvements/changes were required this time around: (r229269-r229278)
import fileinput
import sys
import re
pat = re.compile(r"((?:=|:|^)\s*load (?:atomic )?(?:volatile )?(.*?))(| addrspace\(\d+\) *)\*($| *(?:%|@|null|undef|blockaddress|getelementptr|addrspacecast|bitcast|inttoptr|\[\[[a-zA-Z]|\{\{).*$)")
for line in sys.stdin:
sys.stdout.write(re.sub(pat, r"\1, \2\3*\4", line))
Reviewers: rafael, dexonsmith, grosser
Differential Revision: http://reviews.llvm.org/D7649
llvm-svn: 230794
Duncan P. N. Exon Smith