Change 'TypeCache' from being an std::map to a llvm::DenseMap.  This reduces codegen time
on one .i file from 403.gcc by 0.5%.

llvm-svn: 99823
diff --git a/clang/lib/CodeGen/CGDebugInfo.cpp b/clang/lib/CodeGen/CGDebugInfo.cpp
index 97e99ea..d8a9f36 100644
--- a/clang/lib/CodeGen/CGDebugInfo.cpp
+++ b/clang/lib/CodeGen/CGDebugInfo.cpp
@@ -1212,7 +1212,7 @@
   Ty = UnwrapTypeForDebugInfo(Ty);
   
   // Check for existing entry.
-  std::map<void *, llvm::WeakVH>::iterator it =
+  llvm::DenseMap<void *, llvm::WeakVH>::iterator it =
     TypeCache.find(Ty.getAsOpaquePtr());
   if (it != TypeCache.end()) {
     // Verify that the debug info still exists.