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author | Chris Lattner <sabre@nondot.org> | 2010-02-11 04:40:44 +0000 |
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committer | Chris Lattner <sabre@nondot.org> | 2010-02-11 04:40:44 +0000 |
commit | 1e452650c6044735b6aa922d41736bda5721adcc (patch) | |
tree | 2d20ad4f2dcf838bbf4e1c48ff1473508a3b5663 /lib | |
parent | 26d0e892e36e8dcc4248a8ccc8bedbd2d235eaee (diff) | |
download | external_llvm-1e452650c6044735b6aa922d41736bda5721adcc.zip external_llvm-1e452650c6044735b6aa922d41736bda5721adcc.tar.gz external_llvm-1e452650c6044735b6aa922d41736bda5721adcc.tar.bz2 |
Make jump threading honor x|undef -> true and x&undef -> false,
instead of considering x|undef -> x, which may not be true.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@95850 91177308-0d34-0410-b5e6-96231b3b80d8
Diffstat (limited to 'lib')
-rw-r--r-- | lib/Transforms/Scalar/JumpThreading.cpp | 11 |
1 files changed, 8 insertions, 3 deletions
diff --git a/lib/Transforms/Scalar/JumpThreading.cpp b/lib/Transforms/Scalar/JumpThreading.cpp index 3eff3d8..02346a1 100644 --- a/lib/Transforms/Scalar/JumpThreading.cpp +++ b/lib/Transforms/Scalar/JumpThreading.cpp @@ -336,13 +336,18 @@ ComputeValueKnownInPredecessors(Value *V, BasicBlock *BB,PredValueInfo &Result){ else InterestingVal = ConstantInt::getFalse(I->getContext()); - // Scan for the sentinel. + // Scan for the sentinel. If we find an undef, force it to the + // interesting value: x|undef -> true and x&undef -> false. for (unsigned i = 0, e = LHSVals.size(); i != e; ++i) - if (LHSVals[i].first == InterestingVal || LHSVals[i].first == 0) + if (LHSVals[i].first == InterestingVal || LHSVals[i].first == 0) { Result.push_back(LHSVals[i]); + Result.back().first = InterestingVal; + } for (unsigned i = 0, e = RHSVals.size(); i != e; ++i) - if (RHSVals[i].first == InterestingVal || RHSVals[i].first == 0) + if (RHSVals[i].first == InterestingVal || RHSVals[i].first == 0) { Result.push_back(RHSVals[i]); + Result.back().first = InterestingVal; + } return !Result.empty(); } |