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| author | Andrew Trick <atrick@apple.com> | 2011-11-29 02:16:38 +0000 |
|---|---|---|
| committer | Andrew Trick <atrick@apple.com> | 2011-11-29 02:16:38 +0000 |
| commit | ecb35ece5c42d89057da3c2c7bc2e95f08b1dbef (patch) | |
| tree | 14cfd5aa0655419ef4e01ac717f4045c1246d524 /lib/Transforms/Scalar/IndVarSimplify.cpp | |
| parent | 121d78f7e7d71dc56699f249f5103562d9ce179e (diff) | |
| download | external_llvm-ecb35ece5c42d89057da3c2c7bc2e95f08b1dbef.zip external_llvm-ecb35ece5c42d89057da3c2c7bc2e95f08b1dbef.tar.gz external_llvm-ecb35ece5c42d89057da3c2c7bc2e95f08b1dbef.tar.bz2 | |
SCEV fix. In general, Add/Mul expressions should not inherit NSW/NUW.
This reverts r139450, fixes r139453, and adds much needed comments and a
unit test.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@145367 91177308-0d34-0410-b5e6-96231b3b80d8
Diffstat (limited to 'lib/Transforms/Scalar/IndVarSimplify.cpp')
| -rw-r--r-- | lib/Transforms/Scalar/IndVarSimplify.cpp | 8 |
1 files changed, 6 insertions, 2 deletions
diff --git a/lib/Transforms/Scalar/IndVarSimplify.cpp b/lib/Transforms/Scalar/IndVarSimplify.cpp index 1f5ba51..ea083e3 100644 --- a/lib/Transforms/Scalar/IndVarSimplify.cpp +++ b/lib/Transforms/Scalar/IndVarSimplify.cpp @@ -944,9 +944,13 @@ const SCEVAddRecExpr* WidenIV::GetExtendedOperandRecurrence(NarrowIVDefUse DU) { else return 0; + // When creating this AddExpr, don't apply the current operations NSW or NUW + // flags. This instruction may be guarded by control flow that the no-wrap + // behavior depends on. Non-control-equivalent instructions can be mapped to + // the same SCEV expression, and it would be incorrect to transfer NSW/NUW + // semantics to those operations. const SCEVAddRecExpr *AddRec = dyn_cast<SCEVAddRecExpr>( - SE->getAddExpr(SE->getSCEV(DU.WideDef), ExtendOperExpr, - IsSigned ? SCEV::FlagNSW : SCEV::FlagNUW)); + SE->getAddExpr(SE->getSCEV(DU.WideDef), ExtendOperExpr)); if (!AddRec || AddRec->getLoop() != L) return 0; |