| Message ID | 20221118094754.242910-16-richard.henderson@linaro.org |
|---|---|
| State | New |
| Headers | show |
| Series | tcg: Improve atomicity support | expand |
On 18/11/22 10:47, Richard Henderson wrote: > Adding a vector type will make it easier to handle i386 > have_atomic16 via AVX. > > Signed-off-by: Richard Henderson <richard.henderson@linaro.org> > --- > include/qemu/int128.h | 10 +++++----- > 1 file changed, 5 insertions(+), 5 deletions(-) Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
On 18/11/22 10:47, Richard Henderson wrote: > Adding a vector type will make it easier to handle i386 > have_atomic16 via AVX. > > Signed-off-by: Richard Henderson <richard.henderson@linaro.org> > --- > include/qemu/int128.h | 10 +++++----- > 1 file changed, 5 insertions(+), 5 deletions(-) > > diff --git a/include/qemu/int128.h b/include/qemu/int128.h > index f62a46b48c..f29f90e6f4 100644 > --- a/include/qemu/int128.h > +++ b/include/qemu/int128.h > @@ -479,16 +479,16 @@ static inline void bswap128s(Int128 *s) > /* > * When compiler supports a 128-bit type, define a combination of > * a possible structure and the native types. Ease parameter passing > - * via use of the transparent union extension. > + * via use of the transparent union extension. Provide a vector type > + * for use in atomicity on some hosts. > */ > -#ifdef CONFIG_INT128 > typedef union { > Int128 s; > + uint64_t v __attribute__((vector_size(16))); > +#ifdef CONFIG_INT128 > __int128_t i; > __uint128_t u; > -} Int128Alias __attribute__((transparent_union)); > -#else > -typedef Int128 Int128Alias; > #endif /* CONFIG_INT128 */ > +} Int128Alias __attribute__((transparent_union)); > > #endif /* INT128_H */ This triggers a warning with GCC: include/qemu/int128.h:487:14: warning: alignment of field 'v' (128 bits) does not match the alignment of the first field in transparent union; transparent_union attribute ignored [-Wignored-attributes] uint64_t v __attribute__((vector_size(16))); ^ include/qemu/int128.h:486:12: note: alignment of first field is 64 bits Int128 s; ^ Meson: Project version: 7.1.91 C compiler for the host machine: gcc-12 (gcc 12.2.0 "gcc-12 (Homebrew GCC 12.2.0) 12.2.0") C linker for the host machine: gcc-12 ld64 819.6 Host machine cpu family: aarch64 Host machine cpu: arm64
On 22/11/22 19:21, Philippe Mathieu-Daudé wrote: > On 18/11/22 10:47, Richard Henderson wrote: >> Adding a vector type will make it easier to handle i386 >> have_atomic16 via AVX. >> >> Signed-off-by: Richard Henderson <richard.henderson@linaro.org> >> --- >> include/qemu/int128.h | 10 +++++----- >> 1 file changed, 5 insertions(+), 5 deletions(-) >> >> diff --git a/include/qemu/int128.h b/include/qemu/int128.h >> index f62a46b48c..f29f90e6f4 100644 >> --- a/include/qemu/int128.h >> +++ b/include/qemu/int128.h >> @@ -479,16 +479,16 @@ static inline void bswap128s(Int128 *s) >> /* >> * When compiler supports a 128-bit type, define a combination of >> * a possible structure and the native types. Ease parameter passing >> - * via use of the transparent union extension. >> + * via use of the transparent union extension. Provide a vector type >> + * for use in atomicity on some hosts. >> */ >> -#ifdef CONFIG_INT128 >> typedef union { >> Int128 s; >> + uint64_t v __attribute__((vector_size(16))); >> +#ifdef CONFIG_INT128 >> __int128_t i; >> __uint128_t u; >> -} Int128Alias __attribute__((transparent_union)); >> -#else >> -typedef Int128 Int128Alias; >> #endif /* CONFIG_INT128 */ >> +} Int128Alias __attribute__((transparent_union)); >> #endif /* INT128_H */ > > This triggers a warning with GCC: Ah no, looking closer, even configured as ''--cc=gcc-12 --host-cc=gcc-12 --cxx=/bin/false', Clang got selected for ObjC, and this warning comes from it: Compiling Objective-C object libcommon.fa.p/ui_cocoa.m.o In file included from ../../ui/cocoa.m:36: In file included from include/sysemu/sysemu.h:5: In file included from include/qemu/timer.h:4: In file included from include/qemu/bitops.h:16: In file included from include/qemu/host-utils.h:35: > include/qemu/int128.h:487:14: warning: alignment of field 'v' (128 bits) > does not match the alignment of the first field in transparent union; > transparent_union attribute ignored [-Wignored-attributes] > uint64_t v __attribute__((vector_size(16))); > ^ > include/qemu/int128.h:486:12: note: alignment of first field is 64 bits > Int128 s; > ^ > Meson: > > Project version: 7.1.91 > C compiler for the host machine: gcc-12 (gcc 12.2.0 "gcc-12 (Homebrew > GCC 12.2.0) 12.2.0") > C linker for the host machine: gcc-12 ld64 819.6 > Host machine cpu family: aarch64 > Host machine cpu: arm64 Objective-C compiler for the host machine: clang (clang 14.0.0) Objective-C linker for the host machine: clang ld64 819.6 Regards, Phil.
diff --git a/include/qemu/int128.h b/include/qemu/int128.h index f62a46b48c..f29f90e6f4 100644 --- a/include/qemu/int128.h +++ b/include/qemu/int128.h @@ -479,16 +479,16 @@ static inline void bswap128s(Int128 *s) /* * When compiler supports a 128-bit type, define a combination of * a possible structure and the native types. Ease parameter passing - * via use of the transparent union extension. + * via use of the transparent union extension. Provide a vector type + * for use in atomicity on some hosts. */ -#ifdef CONFIG_INT128 typedef union { Int128 s; + uint64_t v __attribute__((vector_size(16))); +#ifdef CONFIG_INT128 __int128_t i; __uint128_t u; -} Int128Alias __attribute__((transparent_union)); -#else -typedef Int128 Int128Alias; #endif /* CONFIG_INT128 */ +} Int128Alias __attribute__((transparent_union)); #endif /* INT128_H */
Adding a vector type will make it easier to handle i386 have_atomic16 via AVX. Signed-off-by: Richard Henderson <richard.henderson@linaro.org> --- include/qemu/int128.h | 10 +++++----- 1 file changed, 5 insertions(+), 5 deletions(-)