Fix PR9324 / <rdar://problem/9052489> by handling the case where a PHI has no uses.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@126567 91177308-0d34-0410-b5e6-96231b3b80d8

include/llvm/CodeGen/FunctionLoweringInfo.h

@@ -187,7 +187,12 @@ public:
   /// InvalidatePHILiveOutRegInfo - Invalidates a PHI's LiveOutInfo, to be
   /// called when a block is visited before all of its predecessors.
   void InvalidatePHILiveOutRegInfo(const PHINode *PN) {
-    unsigned Reg = ValueMap[PN];
+    // PHIs with no uses have no ValueMap entry.
+    DenseMap<const Value*, unsigned>::const_iterator It = ValueMap.find(PN);
+    if (It == ValueMap.end())
+      return;
+
+    unsigned Reg = It->second;
     LiveOutRegInfo.grow(Reg);
     LiveOutRegInfo[Reg].IsValid = false;
   }