Make sure we use the right insertion point when instcombine replaces a PHI with another instruction. (Specifically, don't insert an arbitrary instruction before a PHI.) Fixes PR11275.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@143437 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Transforms/InstCombine/InstructionCombining.cpp b/lib/Transforms/InstCombine/InstructionCombining.cpp
index 288fe68..0cc969b 100644
--- a/lib/Transforms/InstCombine/InstructionCombining.cpp
+++ b/lib/Transforms/InstCombine/InstructionCombining.cpp
@@ -2028,9 +2028,10 @@
BasicBlock *InstParent = I->getParent();
BasicBlock::iterator InsertPos = I;
- if (!isa<PHINode>(Result)) // If combining a PHI, don't insert
- while (isa<PHINode>(InsertPos)) // middle of a block of PHIs.
- ++InsertPos;
+ // If we replace a PHI with something that isn't a PHI, fix up the
+ // insertion point.
+ if (!isa<PHINode>(Result) && isa<PHINode>(InsertPos))
+ InsertPos = InstParent->getFirstInsertionPt();
InstParent->getInstList().insert(InsertPos, Result);