On 10 December 2015 at 08:42, Oded Gabbay <oded.gab...@gmail.com> wrote: > On Wed, Dec 9, 2015 at 8:30 PM, Matt Turner <matts...@gmail.com> wrote: >> On Tue, Dec 8, 2015 at 9:37 PM, Jonathan Gray <j...@jsg.id.au> wrote: >>> Change the __m128i variables to be volatile so gcc 4.9 won't optimise >>> all of them out with -O1 or greater. The _mm_set1_epi32/pinsrd calls >>> still get optimised out but now there is at least one SSE4.1 instruction >>> generated via _mm_max_epu32/pmaxud. When all of the sse4.1 instructions >>> got optimised out the configure test would incorrectly pass when the >>> compiler supported the intrinsics and the assembler didn't support the >>> instructions. >>> >>> Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=91806 >>> Signed-off-by: Jonathan Gray <j...@jsg.id.au> >>> Cc: "11.0 11.1" <mesa-sta...@lists.freedesktop.org> >>> --- >>> configure.ac | 2 +- >>> 1 file changed, 1 insertion(+), 1 deletion(-) >>> >>> diff --git a/configure.ac b/configure.ac >>> index 260934d..1d82e47 100644 >>> --- a/configure.ac >>> +++ b/configure.ac >>> @@ -384,7 +384,7 @@ CFLAGS="$SSE41_CFLAGS $CFLAGS" >>> AC_COMPILE_IFELSE([AC_LANG_SOURCE([[ >>> #include <smmintrin.h> >>> int main () { >>> - __m128i a = _mm_set1_epi32 (0), b = _mm_set1_epi32 (0), c; >>> + volatile __m128i a = _mm_set1_epi32 (0), b = _mm_set1_epi32 (0), c; >>> c = _mm_max_epu32(a, b); >>> return 0; >> >> I would have extracted an int from the result of _mm_max_epu32 and >> returned that instead of 0. > > Instead of the volatile I assume ? > Precisely. If anyone wants to follow on Matt's suggestion we can pick that one as well. I'd like to get a patch for the next stable releases (next Friday for 11.0.x and just after new year for 11.1.1) so I'll take whatever's around :-)
-Emil _______________________________________________ mesa-dev mailing list mesa-dev@lists.freedesktop.org http://lists.freedesktop.org/mailman/listinfo/mesa-dev
