From b8bac2f99b5807f24b0ed4cdaad8ad09af149ff1 Mon Sep 17 00:00:00 2001 From: Oded Gabbay Date: Fri, 18 Dec 2015 12:25:53 +0000 Subject: [PATCH] configura.ac: fix test for SSE4.1 assembler support This patch modifies the SSE4.1 test in configure.ac to use a global variable to initialize vector variables. In addition, we now return the value of the computation instead of 0. This is done so gcc 4.9 (and lower) won't optimize the SSE4.1 assembly instructions (when using -O1 and higher), because then the configure test might incorrectly pass even though the assembler doesn't support the SSE4.1 instructions (the test will pass because the compiler does support the intrinsics). Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=91806 Cc: "11.0 11.1" Signed-off-by: Oded Gabbay Reviewed-by: Emil Velikov (cherry picked from commit 6e44bbe0f5496b1aea2b4a29adae7990b62fda33) --- configure.ac | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) diff --git a/configure.ac b/configure.ac index fa37bd11b9c..98fe173c6e8 100644 --- a/configure.ac +++ b/configure.ac @@ -375,10 +375,11 @@ save_CFLAGS="$CFLAGS" CFLAGS="$SSE41_CFLAGS $CFLAGS" AC_COMPILE_IFELSE([AC_LANG_SOURCE([[ #include +int param; int main () { - __m128i a = _mm_set1_epi32 (0), b = _mm_set1_epi32 (0), c; + __m128i a = _mm_set1_epi32 (param), b = _mm_set1_epi32 (param + 1), c; c = _mm_max_epu32(a, b); - return 0; + return _mm_cvtsi128_si32(c); }]])], SSE41_SUPPORTED=1) CFLAGS="$save_CFLAGS" if test "x$SSE41_SUPPORTED" = x1; then -- 2.11.0