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| author | Eli Friedman <eli.friedman@gmail.com> | 2011-03-09 00:48:33 +0000 |
|---|---|---|
| committer | Eli Friedman <eli.friedman@gmail.com> | 2011-03-09 00:48:33 +0000 |
| commit | 2adc5b6a17268834b08fda444b1a84550e8c5ae8 (patch) | |
| tree | ed1fb5ac8ad6f42756bf8e23b079f4eb890d01f9 /lib/Transforms/Utils/SimplifyCFG.cpp | |
| parent | e11128dd9d85b595b3fa03d0d8a52f0ae62cc11c (diff) | |
PR9420; an instruction before an unreachable is guaranteed not to have any
reachable uses, but there still might be uses in dead blocks. Use the
standard solution of replacing all the uses with undef. This is
a rare case because it's very sensitive to phase ordering in SimplifyCFG.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@127299 91177308-0d34-0410-b5e6-96231b3b80d8
Diffstat (limited to 'lib/Transforms/Utils/SimplifyCFG.cpp')
| -rw-r--r-- | lib/Transforms/Utils/SimplifyCFG.cpp | 4 |
1 files changed, 3 insertions, 1 deletions
diff --git a/lib/Transforms/Utils/SimplifyCFG.cpp b/lib/Transforms/Utils/SimplifyCFG.cpp index 72fa468db6..09f4fb2e13 100644 --- a/lib/Transforms/Utils/SimplifyCFG.cpp +++ b/lib/Transforms/Utils/SimplifyCFG.cpp @@ -2168,7 +2168,9 @@ bool SimplifyCFGOpt::SimplifyUnreachable(UnreachableInst *UI) { if (LI->isVolatile()) break; - // Delete this instruction + // Delete this instruction (any uses are guaranteed to be dead) + if (!BBI->use_empty()) + BBI->replaceAllUsesWith(UndefValue::get(BBI->getType())); BBI->eraseFromParent(); Changed = true; } |