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| author | Chris Lattner <sabre@nondot.org> | 2009-11-12 05:24:05 +0000 |
|---|---|---|
| committer | Chris Lattner <sabre@nondot.org> | 2009-11-12 05:24:05 +0000 |
| commit | 66c04c48debfd4357beaf9310346b2b24046b685 (patch) | |
| tree | 21ae6fe818b545a074550b4d53b7bc1e221bf3ac /lib/Transforms/Scalar/JumpThreading.cpp | |
| parent | f496e79f44f13ac80564f5f8e69aa648033e7889 (diff) | |
| download | llvm-66c04c48debfd4357beaf9310346b2b24046b685.tar.gz llvm-66c04c48debfd4357beaf9310346b2b24046b685.tar.bz2 llvm-66c04c48debfd4357beaf9310346b2b24046b685.tar.xz | |
use getPredicateOnEdge to fold comparisons through PHI nodes,
which implements GCC PR18046. This also gets us 360 more
jump threads on 176.gcc.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@86953 91177308-0d34-0410-b5e6-96231b3b80d8
Diffstat (limited to 'lib/Transforms/Scalar/JumpThreading.cpp')
| -rw-r--r-- | lib/Transforms/Scalar/JumpThreading.cpp | 12 |
1 files changed, 11 insertions, 1 deletions
diff --git a/lib/Transforms/Scalar/JumpThreading.cpp b/lib/Transforms/Scalar/JumpThreading.cpp index 1bfad2d5d7..d5ce86aca0 100644 --- a/lib/Transforms/Scalar/JumpThreading.cpp +++ b/lib/Transforms/Scalar/JumpThreading.cpp @@ -368,7 +368,17 @@ ComputeValueKnownInPredecessors(Value *V, BasicBlock *BB,PredValueInfo &Result){ Value *RHS = Cmp->getOperand(1)->DoPHITranslation(BB, PredBB); Value *Res = SimplifyCmpInst(Cmp->getPredicate(), LHS, RHS, TD); - if (Res == 0) continue; + if (Res == 0) { + if (!LVI || !isa<Constant>(RHS)) + continue; + + LazyValueInfo::Tristate + ResT = LVI->getPredicateOnEdge(Cmp->getPredicate(), LHS, + cast<Constant>(RHS), PredBB, BB); + if (ResT == LazyValueInfo::Unknown) + continue; + Res = ConstantInt::get(Type::getInt1Ty(LHS->getContext()), ResT); + } if (isa<UndefValue>(Res)) Result.push_back(std::make_pair((ConstantInt*)0, PredBB)); |