aaron.ballman added inline comments.
================ Comment at: lib/Sema/SemaChecking.cpp:7711-7715 + // It's an integer promotion if the destination type is the promoted + // source type. + return ICE->getCastKind() == CK_IntegralCast && + From->isPromotableIntegerType() && + S.Context.getPromotedIntegerType(From) == To; ---------------- ebevhan wrote: > aaron.ballman wrote: > > This check is not checking against the promoted type of the bit-field. See > > `Sema::UsualArithmeticConversions()` for an example of what I'm talking > > about. Is that expected? > I'm not entirely sure what you mean. Are you referring to the type produced > by `isPromotableBitField`? The source type of that promotion is what we don't > want to see in these implicit casts. > > We don't want to look through promotions here if we promoted from a type > which was the result of a bitfield promotion, and that bitfield promotion was > from a higher ranked type to a lower ranked type. so, if we have a bitfield > of type `short`, then promoting that to `int` is fine, and we will give a > warning for the `short`. But if the type of the bitfield is `long`, it could > be promoted to `int`. However, the format specifier warning will look through > these promotions and think that we passed an expression of `long` to the > function even though it was `int`. Ahhh, okay, I see what's going on then. This makes more sense to me now, thank you for the explanation. ================ Comment at: test/Sema/format-strings-bitfield-promotion.c:1 +// RUN: %clang_cc1 -triple x86_64-unknown-unknown -fsyntax-only -verify %s + ---------------- aaron.ballman wrote: > Running your test through GCC looks like the behavior matches here for C; can > you also add a C++ test that demonstrates the behavior does not change? > > https://godbolt.org/z/zRYDMG Strangely, the above godbolt link dropped the output windows, here's a different link that shows the behavioral differences between C and C++ mode in GCC: https://godbolt.org/z/R3zRHe CHANGES SINCE LAST ACTION https://reviews.llvm.org/D51211/new/ https://reviews.llvm.org/D51211 _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org http://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
