[llvm] r220468 - Assert that ValueHandleBase::ValueIsRAUWd doesn't change the tracked Value type.

[Frederic Riss]

Author: friss
Date: Wed Oct 22 23:08:42 2014
New Revision: 220468

URL: http://llvm.org/viewvc/llvm-project?rev=220468&view=rev
Log:
Assert that ValueHandleBase::ValueIsRAUWd doesn't change the tracked Value type.

This invariant is enforced in Value::replaceAllUsesWith, thus it seems
logical to apply it also to ValueHandles. This commit fixes InstCombine
to not trigger the assertion during the removal of constant bitcasts in
call instructions.

Differential Revision: http://reviews.llvm.org/D5828

Modified:
    llvm/trunk/lib/IR/Value.cpp
    llvm/trunk/lib/Transforms/InstCombine/InstCombineCalls.cpp

Modified: llvm/trunk/lib/IR/Value.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/IR/Value.cpp?rev=220468&r1=220467&r2=220468&view=diff
==============================================================================
--- llvm/trunk/lib/IR/Value.cpp (original)
+++ llvm/trunk/lib/IR/Value.cpp Wed Oct 22 23:08:42 2014
@@ -773,6 +773,8 @@ void ValueHandleBase::ValueIsDeleted(Val
 void ValueHandleBase::ValueIsRAUWd(Value *Old, Value *New) {
   assert(Old->HasValueHandle &&"Should only be called if ValueHandles present");
   assert(Old != New && "Changing value into itself!");
+  assert(Old->getType() == New->getType() &&
+         "replaceAllUses of value with new value of different type!");
 
   // Get the linked list base, which is guaranteed to exist since the
   // HasValueHandle flag is set.

Modified: llvm/trunk/lib/Transforms/InstCombine/InstCombineCalls.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/InstCombine/InstCombineCalls.cpp?rev=220468&r1=220467&r2=220468&view=diff
==============================================================================
--- llvm/trunk/lib/Transforms/InstCombine/InstCombineCalls.cpp (original)
+++ llvm/trunk/lib/Transforms/InstCombine/InstCombineCalls.cpp Wed Oct 22 23:08:42 2014
@@ -1370,7 +1370,7 @@ bool InstCombiner::transformConstExprCas
       if (!Caller->use_empty() &&
           // void -> non-void is handled specially
           !NewRetTy->isVoidTy())
-      return false;   // Cannot transform this return value.
+        return false;   // Cannot transform this return value.
     }
 
     if (!CallerPAL.isEmpty() && !Caller->use_empty()) {
@@ -1589,8 +1589,14 @@ bool InstCombiner::transformConstExprCas
 
   if (!Caller->use_empty())
     ReplaceInstUsesWith(*Caller, NV);
-  else if (Caller->hasValueHandle())
-    ValueHandleBase::ValueIsRAUWd(Caller, NV);
+  else if (Caller->hasValueHandle()) {
+    if (OldRetTy == NV->getType())
+      ValueHandleBase::ValueIsRAUWd(Caller, NV);
+    else
+      // We cannot call ValueIsRAUWd with a different type, and the
+      // actual tracked value will disappear.
+      ValueHandleBase::ValueIsDeleted(Caller);
+  }
 
   EraseInstFromFunction(*Caller);
   return true;