Don't add the instruction about to be RAUW'ed and erased to the

worklist. This can happen in theory when an instruction uses itself,
such as a PHI node. This was spotted by inspection, and unfortunately
I've not been able to come up with a test case that would trigger it. If
anyone has ideas, let me know...

llvm-svn: 153396

1 files changed, 4 insertions, 2 deletions

diff --git a/llvm/lib/Analysis/InstructionSimplify.cpp b/llvm/lib/Analysis/InstructionSimplify.cpp
index 95d02efd789..c8fb6ae595b 100644
--- a/llvm/lib/Analysis/InstructionSimplify.cpp
+++ b/llvm/lib/Analysis/InstructionSimplify.cpp
@@ -2841,7 +2841,8 @@ static bool replaceAndRecursivelySimplifyImpl(Instruction *I, Value *SimpleV,
   if (SimpleV) {
     for (Value::use_iterator UI = I->use_begin(), UE = I->use_end(); UI != UE;
          ++UI)
-      Worklist.push_back(cast<Instruction>(*UI));
+      if (*UI != I)
+        Worklist.push_back(cast<Instruction>(*UI));
 
     // Replace the instruction with its simplified value.
     I->replaceAllUsesWith(SimpleV);
@@ -2869,7 +2870,8 @@ static bool replaceAndRecursivelySimplifyImpl(Instruction *I, Value *SimpleV,
     // uses of To on the recursive step in most cases.
     for (Value::use_iterator UI = I->use_begin(), UE = I->use_end(); UI != UE;
          ++UI)
-      Worklist.push_back(cast<Instruction>(*UI));
+      if (*UI != I)
+        Worklist.push_back(cast<Instruction>(*UI));
 
     // Replace the instruction with its simplified value.
     I->replaceAllUsesWith(SimpleV);