Should be fixed in r336013. Thanks for pointing this out. On Fri, 29 Jun 2018 at 11:24, Galina Kistanova via cfe-commits < cfe-commits@lists.llvm.org> wrote:
> Hello Richard, > > This commit broke tests at one of our builders: > > http://lab.llvm.org:8011/builders/llvm-clang-x86_64-expensive-checks-win/builds/10599 > > Failing Tests (1): > Clang :: CXX/conv/conv.prom/p5.cpp > > Please have a look? > > Thanks > > Galina > > On Thu, Jun 28, 2018 at 2:17 PM, Richard Smith via cfe-commits < > cfe-commits@lists.llvm.org> wrote: > >> Author: rsmith >> Date: Thu Jun 28 14:17:55 2018 >> New Revision: 335925 >> >> URL: http://llvm.org/viewvc/llvm-project?rev=335925&view=rev >> Log: >> PR37979: integral promotions in C++ treat enum bit-fields like enums, >> not like bit-fields. >> >> We used to get this right "by accident", because conversions for the >> selected built-in overloaded operator would convert the enum bit-field >> to its corresponding underlying type early. But after DR1687 that no >> longer happens. >> >> Technically this change should also apply to C, where bit-fields only >> have special promotion rules if the bit-field's declared type is >> _Bool, int, signed int, or unsigned int, but for GCC compatibility we >> only look at the bit-width and not the underlying type when performing >> bit-field integral promotions in C. >> >> Added: >> cfe/trunk/test/CXX/conv/conv.prom/p5.cpp >> Modified: >> cfe/trunk/lib/AST/ASTContext.cpp >> cfe/trunk/lib/Sema/SemaOverload.cpp >> >> Modified: cfe/trunk/lib/AST/ASTContext.cpp >> URL: >> http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/AST/ASTContext.cpp?rev=335925&r1=335924&r2=335925&view=diff >> >> ============================================================================== >> --- cfe/trunk/lib/AST/ASTContext.cpp (original) >> +++ cfe/trunk/lib/AST/ASTContext.cpp Thu Jun 28 14:17:55 2018 >> @@ -5456,6 +5456,12 @@ QualType ASTContext::isPromotableBitFiel >> if (E->isTypeDependent() || E->isValueDependent()) >> return {}; >> >> + // C++ [conv.prom]p5: >> + // If the bit-field has an enumerated type, it is treated as any >> other >> + // value of that type for promotion purposes. >> + if (getLangOpts().CPlusPlus && E->getType()->isEnumeralType()) >> + return {}; >> + >> // FIXME: We should not do this unless E->refersToBitField() is true. >> This >> // matters in C where getSourceBitField() will find bit-fields for >> various >> // cases where the source expression is not a bit-field designator. >> @@ -5482,13 +5488,15 @@ QualType ASTContext::isPromotableBitFiel >> // >> // FIXME: C does not permit promotion of a 'long : 3' bitfield to int. >> // We perform that promotion here to match GCC and C++. >> + // FIXME: C does not permit promotion of an enum bit-field whose rank >> is >> + // greater than that of 'int'. We perform that promotion to >> match GCC. >> if (BitWidth < IntSize) >> return IntTy; >> >> if (BitWidth == IntSize) >> return FT->isSignedIntegerType() ? IntTy : UnsignedIntTy; >> >> - // Types bigger than int are not subject to promotions, and therefore >> act >> + // Bit-fields wider than int are not subject to promotions, and >> therefore act >> // like the base type. GCC has some weird bugs in this area that we >> // deliberately do not follow (GCC follows a pre-standard resolution to >> // C's DR315 which treats bit-width as being part of the type, and >> this leaks >> >> Modified: cfe/trunk/lib/Sema/SemaOverload.cpp >> URL: >> http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Sema/SemaOverload.cpp?rev=335925&r1=335924&r2=335925&view=diff >> >> ============================================================================== >> --- cfe/trunk/lib/Sema/SemaOverload.cpp (original) >> +++ cfe/trunk/lib/Sema/SemaOverload.cpp Thu Jun 28 14:17:55 2018 >> @@ -2007,6 +2007,14 @@ bool Sema::IsIntegralPromotion(Expr *Fro >> isCompleteType(From->getLocStart(), FromType)) >> return Context.hasSameUnqualifiedType( >> ToType, FromEnumType->getDecl()->getPromotionType()); >> + >> + // C++ [conv.prom]p5: >> + // If the bit-field has an enumerated type, it is treated as any >> other >> + // value of that type for promotion purposes. >> + // >> + // ... so do not fall through into the bit-field checks below in C++. >> + if (getLangOpts().CPlusPlus) >> + return false; >> } >> >> // C++0x [conv.prom]p2: >> @@ -2054,6 +2062,11 @@ bool Sema::IsIntegralPromotion(Expr *Fro >> // other value of that type for promotion purposes (C++ 4.5p3). >> // FIXME: We should delay checking of bit-fields until we actually >> perform the >> // conversion. >> + // >> + // FIXME: In C, only bit-fields of types _Bool, int, or unsigned int >> may be >> + // promoted, per C11 6.3.1.1/2. We promote all bit-fields (including >> enum >> + // bit-fields and those whose underlying type is larger than int) for >> GCC >> + // compatibility. >> if (From) { >> if (FieldDecl *MemberDecl = From->getSourceBitField()) { >> llvm::APSInt BitWidth; >> >> Added: cfe/trunk/test/CXX/conv/conv.prom/p5.cpp >> URL: >> http://llvm.org/viewvc/llvm-project/cfe/trunk/test/CXX/conv/conv.prom/p5.cpp?rev=335925&view=auto >> >> ============================================================================== >> --- cfe/trunk/test/CXX/conv/conv.prom/p5.cpp (added) >> +++ cfe/trunk/test/CXX/conv/conv.prom/p5.cpp Thu Jun 28 14:17:55 2018 >> @@ -0,0 +1,19 @@ >> +// RUN: %clang_cc1 -verify %s >> +// expected-no-diagnostics >> + >> +// A prvalue for an integral bit-field can be converted to a prvalue of >> type >> +// int if int can represent all the values of the bit-field >> +struct X { long long e : 1; }; >> +static_assert(sizeof(+X().e) == sizeof(int), ""); >> +static_assert(sizeof(X().e + 1) == sizeof(int), ""); >> +static_assert(sizeof(true ? X().e : 0) == sizeof(int), ""); >> + >> +enum E { a = __LONG_LONG_MAX__ }; >> +static_assert(sizeof(E{}) == sizeof(long long), ""); >> + >> +// If the bit-field has an enumerated type, it is treated as any other >> value of >> +// that [enumerated] type for promotion purposes. >> +struct Y { E e : 1; }; >> +static_assert(sizeof(+Y().e) == sizeof(long long), ""); >> +static_assert(sizeof(Y().e + 1) == sizeof(long long), ""); >> +static_assert(sizeof(true ? Y().e : 0) == sizeof(long long), ""); >> >> >> _______________________________________________ >> cfe-commits mailing list >> cfe-commits@lists.llvm.org >> http://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits >> > > _______________________________________________ > cfe-commits mailing list > cfe-commits@lists.llvm.org > http://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits >
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