Don't warn about case-value conversions from a negative value to a
larger unsigned value, since this is implementation-defined
behavior. (We previously suppressed this warning when converting from
a signed value to an unsigned value of the same size).
llvm-svn: 97430
diff --git a/clang/lib/Sema/SemaStmt.cpp b/clang/lib/Sema/SemaStmt.cpp
index bdd0962..540189c 100644
--- a/clang/lib/Sema/SemaStmt.cpp
+++ b/clang/lib/Sema/SemaStmt.cpp
@@ -314,15 +314,13 @@
// Perform a conversion to the promoted condition type if needed.
if (NewWidth > Val.getBitWidth()) {
// If this is an extension, just do it.
- llvm::APSInt OldVal(Val);
Val.extend(NewWidth);
-
- // If the input was signed and negative and the output is unsigned,
- // warn.
- if (!NewSign && OldVal.isSigned() && OldVal.isNegative())
- Diag(Loc, DiagID) << OldVal.toString(10) << Val.toString(10);
-
Val.setIsSigned(NewSign);
+
+ // If the input was signed and negative and the output is
+ // unsigned, don't bother to warn: this is implementation-defined
+ // behavior.
+ // FIXME: Introduce a second, default-ignored warning for this case?
} else if (NewWidth < Val.getBitWidth()) {
// If this is a truncation, check for overflow.
llvm::APSInt ConvVal(Val);