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| author | Dan Gohman <gohman@apple.com> | 2009-10-30 23:15:43 +0000 |
|---|---|---|
| committer | Dan Gohman <gohman@apple.com> | 2009-10-30 23:15:43 +0000 |
| commit | 7f7d97eb73d4aa243646583301c943b1f125bade (patch) | |
| tree | 00b2ad58f98faf0e2e96b525fc30d708f1983307 /llvm/lib/Transforms/Utils/SimplifyCFG.cpp | |
| parent | 5bec30ca5d5d3d74f7cd899dbafed7b82ca4a3fc (diff) | |
| download | bcm5719-llvm-7f7d97eb73d4aa243646583301c943b1f125bade.tar.gz bcm5719-llvm-7f7d97eb73d4aa243646583301c943b1f125bade.zip | |
Add a comment about a missed opportunity.
llvm-svn: 85635
Diffstat (limited to 'llvm/lib/Transforms/Utils/SimplifyCFG.cpp')
| -rw-r--r-- | llvm/lib/Transforms/Utils/SimplifyCFG.cpp | 5 |
1 files changed, 5 insertions, 0 deletions
diff --git a/llvm/lib/Transforms/Utils/SimplifyCFG.cpp b/llvm/lib/Transforms/Utils/SimplifyCFG.cpp index 859b8756666..8e1fb98b704 100644 --- a/llvm/lib/Transforms/Utils/SimplifyCFG.cpp +++ b/llvm/lib/Transforms/Utils/SimplifyCFG.cpp @@ -1753,8 +1753,13 @@ static bool SimplifyCondBranchToCondBranch(BranchInst *PBI, BranchInst *BI) { /// nodes in this block. This doesn't try to be clever about PHI nodes /// which differ only in the order of the incoming values, but instcombine /// orders them so it usually won't matter. +/// static bool EliminateDuplicatePHINodes(BasicBlock *BB) { bool Changed = false; + + // This implementation doesn't currently consider undef operands + // specially. Theroetically, two phis which are identical except for + // one having an undef where the other doesn't could be collapsed. // Map from PHI hash values to PHI nodes. If multiple PHIs have // the same hash value, the element is the first PHI in the |
