Bug fix. Only safe to perform extension uses optimization if the source of extension is also defined in the same BB as the extension.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@44896 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Transforms/Scalar/CodeGenPrepare.cpp b/lib/Transforms/Scalar/CodeGenPrepare.cpp
index 594c017..37a645f 100644
--- a/lib/Transforms/Scalar/CodeGenPrepare.cpp
+++ b/lib/Transforms/Scalar/CodeGenPrepare.cpp
@@ -929,6 +929,11 @@
if (Src->hasOneUse())
return false;
+ // Only safe to perform the optimization if the source is also defined in
+ // this block.
+ if (DefBB != cast<Instruction>(Src)->getParent())
+ return false;
+
bool DefIsLiveOut = false;
for (Value::use_iterator UI = I->use_begin(), E = I->use_end();
UI != E; ++UI) {