Fix bug: Assembler/2003-05-15-AssemblerProblem.llx

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@6234 91177308-0d34-0410-b5e6-96231b3b80d8

2 files changed, 14 insertions, 4 deletions

diff --git a/lib/VMCore/Constants.cpp b/lib/VMCore/Constants.cpp
index 04d46e5867..9efc313be7 100644
--- a/lib/VMCore/Constants.cpp
+++ b/lib/VMCore/Constants.cpp
@@ -721,9 +721,8 @@ unsigned Constant::mutateReferences(Value *OldV, Value *NewV) {
     GlobalValue *OldGV = CPR->getValue();
 
     assert(OldGV == OldV && "Cannot mutate old value if I'm not using it!");
-
-    OldGV->getParent()->mutateConstantPointerRef(OldGV, NewGV);
     Operands[0] = NewGV;
+    OldGV->getParent()->mutateConstantPointerRef(OldGV, NewGV);
     return 1;
   } else {
     Constant *NewC = cast<Constant>(NewV);
diff --git a/lib/VMCore/Module.cpp b/lib/VMCore/Module.cpp
index fe9b828b2b..275d4cfbf3 100644
--- a/lib/VMCore/Module.cpp
+++ b/lib/VMCore/Module.cpp
@@ -250,6 +250,7 @@ void Module::destroyConstantPointerRef(ConstantPointerRef *CPR) {
 }
 
 void Module::mutateConstantPointerRef(GlobalValue *OldGV, GlobalValue *NewGV) {
+  assert(OldGV != NewGV && "Cannot mutate to the same global!");
   GlobalValueRefMap::iterator I = GVRefMap->Map.find(OldGV);
   assert(I != GVRefMap->Map.end() && 
 	 "mutateConstantPointerRef; OldGV not in table!");
@@ -258,6 +259,16 @@ void Module::mutateConstantPointerRef(GlobalValue *OldGV, GlobalValue *NewGV) {
   // Remove the old entry...
   GVRefMap->Map.erase(I);
 
-  // Insert the new entry...
-  GVRefMap->Map.insert(std::make_pair(NewGV, Ref));
+  // Check to see if a CPR already exists for NewGV
+  I = GVRefMap->Map.lower_bound(NewGV);
+
+  if (I == GVRefMap->Map.end() || I->first != NewGV) {
+    // Insert the new entry...
+    GVRefMap->Map.insert(I, std::make_pair(NewGV, Ref));
+  } else {
+    // Otherwise, an entry already exists for the current global value.
+    // Completely replace the old CPR with the existing one...
+    Ref->replaceAllUsesWith(I->second);
+    delete Ref;
+  }
 }