Don't circumvent the debug info type cache when emitting info for EnumConstantDecl.

CreateEnumType doesn't participate in caching so the descriptor for the enum
gets recomputed for every reference of an element of an enum, only to get
discarded when it gets turned into an MDNode.

No functionality change except performance.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@158832 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/CGDebugInfo.cpp b/lib/CodeGen/CGDebugInfo.cpp
index 19ea18c..2fdd7a3 100644
--- a/lib/CodeGen/CGDebugInfo.cpp
+++ b/lib/CodeGen/CGDebugInfo.cpp
@@ -2660,8 +2660,9 @@
   StringRef Name = VD->getName();
   llvm::DIType Ty = getOrCreateType(VD->getType(), Unit);
   if (const EnumConstantDecl *ECD = dyn_cast<EnumConstantDecl>(VD)) {
-    if (const EnumDecl *ED = dyn_cast<EnumDecl>(ECD->getDeclContext()))
-      Ty = CreateEnumType(ED);
+    const EnumDecl *ED = cast<EnumDecl>(ECD->getDeclContext());
+    assert(isa<EnumType>(ED->getTypeForDecl()) && "Enum without EnumType?");
+    Ty = getOrCreateType(QualType(ED->getTypeForDecl(), 0), Unit);
   }
   // Do not use DIGlobalVariable for enums.
   if (Ty.getTag() == llvm::dwarf::DW_TAG_enumeration_type)