[PATCH] D104702: [LSR] Filter out zero factors. PR50765

[Max Kazantsev via Phabricator via llvm-commits]

mkazantsev created this revision.
mkazantsev added reviewers: lebedev.ri, SjoerdMeijer, huihuiz, fhahn.
Herald added a subscriber: hiraditya.
mkazantsev requested review of this revision.
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Zero factor leads to division by zero and failure of corresponding
assert as shown in PR50765. We should filter out such factors.


https://reviews.llvm.org/D104702

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


Index: llvm/test/Transforms/LoopStrengthReduce/pr50765.ll
===================================================================
--- llvm/test/Transforms/LoopStrengthReduce/pr50765.ll
+++ 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.
 
Index: llvm/lib/Transforms/Scalar/LoopStrengthReduce.cpp
===================================================================
--- llvm/lib/Transforms/Scalar/LoopStrengthReduce.cpp
+++ llvm/lib/Transforms/Scalar/LoopStrengthReduce.cpp
@@ -2712,13 +2712,13 @@
       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());
       }
     }


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