Allow PRE to insert no-cost phi nodes

[oota-llvm.git] / lib / Transforms / Utils / GlobalStatus.cpp

diff --git a/lib/Transforms/Utils/GlobalStatus.cpp b/lib/Transforms/Utils/GlobalStatus.cpp
index 33e34a9941e051b921bb0b5b53156533a3f265f9..52e2d59557fa1ff83de31538193855d7b47dd723 100644 (file)
--- a/lib/Transforms/Utils/GlobalStatus.cpp
+++ b/lib/Transforms/Utils/GlobalStatus.cpp
@@ -35,6 +35,9 @@ bool llvm::isSafeToDestroyConstant(const Constant *C) {
   if (isa<GlobalValue>(C))
     return false;
 
+  if (isa<ConstantInt>(C) || isa<ConstantFP>(C))
+    return false;
+
   for (const User *U : C->users())
     if (const Constant *CU = dyn_cast<Constant>(U)) {
       if (!isSafeToDestroyConstant(CU))
@@ -130,7 +133,7 @@ static bool analyzeGlobalAux(const Value *V, GlobalStatus &GS,
       } else if (const PHINode *PN = dyn_cast<PHINode>(I)) {
         // PHI nodes we can check just like select or GEP instructions, but we
         // have to be careful about infinite recursion.
-        if (PhiUsers.insert(PN)) // Not already visited.
+        if (PhiUsers.insert(PN).second) // Not already visited.
           if (analyzeGlobalAux(I, GS, PhiUsers))
             return true;
       } else if (isa<CmpInst>(I)) {