In Twine::str(), if the Twine stores only a std::string, just return a direct copy of that instead of first copying to a SmallString and converting that to a std::string. Also fix some indentation.

llvm-svn: 135267

llvm/lib/Support/Twine.cpp

@@ -14,6 +14,11 @@
 using namespace llvm;
 
 std::string Twine::str() const {
+  // If we're storing only a std::string, just return it.
+  if (LHSKind == StdStringKind && RHSKind == EmptyKind)
+    return *static_cast<const std::string*>(LHS);
+
+  // Otherwise, flatten and copy the contents first.
   SmallString<256> Vec;
   return toStringRef(Vec).str();
 }