[llvm] b7d2c17 - [LSR] Filter out zero factors. PR50765

[Max Kazantsev via llvm-commits]

Author: Max Kazantsev
Date: 2021-06-23T10:43:06+07:00
New Revision: b7d2c173ebbbd48342d498ebc8a1127dbc6d87b1

URL: https://github.com/llvm/llvm-project/commit/b7d2c173ebbbd48342d498ebc8a1127dbc6d87b1
DIFF: https://github.com/llvm/llvm-project/commit/b7d2c173ebbbd48342d498ebc8a1127dbc6d87b1.diff

LOG: [LSR] Filter out zero factors. PR50765

Zero factor leads to division by zero and failure of corresponding
assert as shown in PR50765. We should filter out such factors.

Differential Revision: https://reviews.llvm.org/D104702
Reviewed By: huihuiz, reames

Added: 
    

Modified: 
    llvm/lib/Transforms/Scalar/LoopStrengthReduce.cpp
    llvm/test/Transforms/LoopStrengthReduce/pr50765.ll

Removed: 
    


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diff  --git a/llvm/lib/Transforms/Scalar/LoopStrengthReduce.cpp b/llvm/lib/Transforms/Scalar/LoopStrengthReduce.cpp
index a4cbcd4cffef..5d2d9678ce35 100644
--- a/llvm/lib/Transforms/Scalar/LoopStrengthReduce.cpp
+++ b/llvm/lib/Transforms/Scalar/LoopStrengthReduce.cpp
@@ -2712,13 +2712,13 @@ void LSRInstance::CollectInterestingTypesAndFactors() {
       if (const SCEVConstant *Factor =
             dyn_cast_or_null<SCEVConstant>(getExactSDiv(NewStride, OldStride,
                                                         SE, true))) {
-        if (Factor->getAPInt().getMinSignedBits() <= 64)
+        if (Factor->getAPInt().getMinSignedBits() <= 64 && !Factor->isZero())
           Factors.insert(Factor->getAPInt().getSExtValue());
       } else if (const SCEVConstant *Factor =
                    dyn_cast_or_null<SCEVConstant>(getExactSDiv(OldStride,
                                                                NewStride,
                                                                SE, true))) {
-        if (Factor->getAPInt().getMinSignedBits() <= 64)
+        if (Factor->getAPInt().getMinSignedBits() <= 64 && !Factor->isZero())
           Factors.insert(Factor->getAPInt().getSExtValue());
       }
     }

diff  --git a/llvm/test/Transforms/LoopStrengthReduce/pr50765.ll b/llvm/test/Transforms/LoopStrengthReduce/pr50765.ll
index 0f2968388b34..8ebb0ca4f229 100644
--- a/llvm/test/Transforms/LoopStrengthReduce/pr50765.ll
+++ b/llvm/test/Transforms/LoopStrengthReduce/pr50765.ll
@@ -1,6 +1,4 @@
 ; RUN: opt -S -loop-reduce < %s | FileCheck %s
-; XFAIL: *
-; REQUIRES: asserts
 ;
 ;This test produces zero factor that becomes a denumerator and fails an assetion.