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| author | Peter Collingbourne <peter@pcc.me.uk> | 2015-11-20 01:26:13 +0000 |
|---|---|---|
| committer | Peter Collingbourne <peter@pcc.me.uk> | 2015-11-20 01:26:13 +0000 |
| commit | c85f4ced4d163442019d170282b751852b2e6500 (patch) | |
| tree | ffe06ef1bcff4831aaa1644c3576163f6e86edd8 /llvm/lib/Analysis/ScalarEvolution.cpp | |
| parent | eb027124afc07b00c85a141b1f03b29a5681f840 (diff) | |
| download | bcm5719-llvm-c85f4ced4d163442019d170282b751852b2e6500.tar.gz bcm5719-llvm-c85f4ced4d163442019d170282b751852b2e6500.zip | |
ScalarEvolution: do not set nuw when creating exprs of form <expr> + <all-ones>.
The nuw constraint will not be satisfied unless <expr> == 0.
This bug has been around since r102234 (in 2010!), but was uncovered by
r251052, which introduced more aggressive optimization of nuw scev expressions.
Differential Revision: http://reviews.llvm.org/D14850
llvm-svn: 253627
Diffstat (limited to 'llvm/lib/Analysis/ScalarEvolution.cpp')
| -rw-r--r-- | llvm/lib/Analysis/ScalarEvolution.cpp | 6 |
1 files changed, 2 insertions, 4 deletions
diff --git a/llvm/lib/Analysis/ScalarEvolution.cpp b/llvm/lib/Analysis/ScalarEvolution.cpp index 5f927121fc2..837461a84bb 100644 --- a/llvm/lib/Analysis/ScalarEvolution.cpp +++ b/llvm/lib/Analysis/ScalarEvolution.cpp @@ -7045,16 +7045,14 @@ bool ScalarEvolution::SimplifyICmpOperands(ICmpInst::Predicate &Pred, Pred = ICmpInst::ICMP_ULT; Changed = true; } else if (!getUnsignedRange(LHS).getUnsignedMin().isMinValue()) { - LHS = getAddExpr(getConstant(RHS->getType(), (uint64_t)-1, true), LHS, - SCEV::FlagNUW); + LHS = getAddExpr(getConstant(RHS->getType(), (uint64_t)-1, true), LHS); Pred = ICmpInst::ICMP_ULT; Changed = true; } break; case ICmpInst::ICMP_UGE: if (!getUnsignedRange(RHS).getUnsignedMin().isMinValue()) { - RHS = getAddExpr(getConstant(RHS->getType(), (uint64_t)-1, true), RHS, - SCEV::FlagNUW); + RHS = getAddExpr(getConstant(RHS->getType(), (uint64_t)-1, true), RHS); Pred = ICmpInst::ICMP_UGT; Changed = true; } else if (!getUnsignedRange(LHS).getUnsignedMax().isMaxValue()) { |
