r233457 - A conversion from a scoped enumeration bitfield to an integral type is an

[Richard Smith]

Author: rsmith
Date: Fri Mar 27 19:31:40 2015
New Revision: 233457

URL: http://llvm.org/viewvc/llvm-project?rev=233457&view=rev
Log:
A conversion from a scoped enumeration bitfield to an integral type is an
integral promotion only if it converts to the underlying type or its promoted
type, not if it converts to the promoted type that the bitfield would have it
if were of the underlying type.

Modified:
    cfe/trunk/lib/Sema/SemaOverload.cpp
    cfe/trunk/test/SemaCXX/enum-bitfield.cpp

Modified: cfe/trunk/lib/Sema/SemaOverload.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Sema/SemaOverload.cpp?rev=233457&r1=233456&r2=233457&view=diff
==============================================================================
--- cfe/trunk/lib/Sema/SemaOverload.cpp (original)
+++ cfe/trunk/lib/Sema/SemaOverload.cpp Fri Mar 27 19:31:40 2015
@@ -1752,11 +1752,13 @@ bool Sema::IsIntegralPromotion(Expr *Fro
       return false;
 
     // We can perform an integral promotion to the underlying type of the enum,
-    // even if that's not the promoted type.
+    // even if that's not the promoted type. Note that the check for promoting
+    // the underlying type is based on the type alone, and does not consider
+    // the bitfield-ness of the actual source expression.
     if (FromEnumType->getDecl()->isFixed()) {
       QualType Underlying = FromEnumType->getDecl()->getIntegerType();
       return Context.hasSameUnqualifiedType(Underlying, ToType) ||
-             IsIntegralPromotion(From, Underlying, ToType);
+             IsIntegralPromotion(nullptr, Underlying, ToType);
     }
 
     // We have already pre-calculated the promotion type, so this is trivial.

Modified: cfe/trunk/test/SemaCXX/enum-bitfield.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/SemaCXX/enum-bitfield.cpp?rev=233457&r1=233456&r2=233457&view=diff
==============================================================================
--- cfe/trunk/test/SemaCXX/enum-bitfield.cpp (original)
+++ cfe/trunk/test/SemaCXX/enum-bitfield.cpp Fri Mar 27 19:31:40 2015
@@ -28,3 +28,11 @@ struct D {
   A::B : C;
 };
 }
+
+enum WithUnderlying : unsigned { wu_value };
+struct WithUnderlyingBitfield {
+  WithUnderlying wu : 3;
+} wu = { wu_value };
+int want_unsigned(unsigned);
+int want_unsigned(int) = delete;
+int check_enum_bitfield_promotes_correctly = want_unsigned(wu.wu);