Fix various minor issues find via unreachable code warnings, from
Ahmed Charles!

llvm-svn: 143569
diff --git a/clang/lib/Basic/Targets.cpp b/clang/lib/Basic/Targets.cpp
index da32c93..0df5ed2 100644
--- a/clang/lib/Basic/Targets.cpp
+++ b/clang/lib/Basic/Targets.cpp
@@ -3077,6 +3077,8 @@
                                      TargetInfo::ConstraintInfo &Info) const {
     switch (*Name) {
     default:
+      return false;
+        
     case 'r': // CPU registers.
     case 'd': // Equivalent to "r" unless generating MIPS16 code.
     case 'y': // Equivalent to "r", backwards compatibility only.