If char/short are shorter than int, do not use U as suffix for

constants. Comparing int against a constant of the given type like
UINT8_MAX will otherwise force a promotion to unsigned int, which is
typically not expected.

llvm-svn: 213301

1 files changed, 5 insertions, 1 deletions

diff --git a/clang/lib/Basic/TargetInfo.cpp b/clang/lib/Basic/TargetInfo.cpp
index 8d81035ce80..94ebeb85dea 100644
--- a/clang/lib/Basic/TargetInfo.cpp
+++ b/clang/lib/Basic/TargetInfo.cpp
@@ -118,7 +118,7 @@ const char *TargetInfo::getTypeName(IntType T) {
 
 /// getTypeConstantSuffix - Return the constant suffix for the specified
 /// integer type enum. For example, SignedLong -> "L".
-const char *TargetInfo::getTypeConstantSuffix(IntType T) {
+const char *TargetInfo::getTypeConstantSuffix(IntType T) const {
   switch (T) {
   default: llvm_unreachable("not an integer!");
   case SignedChar:
@@ -127,7 +127,11 @@ const char *TargetInfo::getTypeConstantSuffix(IntType T) {
   case SignedLong:       return "L";
   case SignedLongLong:   return "LL";
   case UnsignedChar:
+    if (getCharWidth() < getIntWidth())
+      return "";
   case UnsignedShort:
+    if (getShortWidth() < getIntWidth())
+      return "";
   case UnsignedInt:      return "U";
   case UnsignedLong:     return "UL";
   case UnsignedLongLong: return "ULL";