[Mesa-dev] [PATCH 1/4] meson: set sse41 flags conditionally based on support

[Tapani Pälli]

Test code is copy-pasted from configure.ac.

Signed-off-by: Tapani Pälli <tapani.palli at intel.com>
---
 meson.build | 37 ++++++++++++++++++++++++++-----------
 1 file changed, 26 insertions(+), 11 deletions(-)

diff --git a/meson.build b/meson.build
index 0d534b9b4a9..4b6fb3781a1 100644
--- a/meson.build
+++ b/meson.build
@@ -844,19 +844,34 @@ foreach a : ['-Werror=pointer-arith', '-Werror=vla']
   endif
 endforeach
 
-if host_machine.cpu_family().startswith('x86')
-  pre_args += '-DUSE_SSE41'
-  with_sse41 = true
-  sse41_args = ['-msse4.1']
+# sse41 defaults to false
+with_sse41 = false
+sse41_args = []
 
-  # GCC on x86 (not x86_64) with -msse* assumes a 16 byte aligned stack, but
-  # that's not guaranteed
-  if host_machine.cpu_family() == 'x86'
-    sse41_args += '-mstackrealign'
+# on x86, x86_64 test if we can support sse41
+if host_machine.cpu_family().startswith('x86')
+  code = '''#include <smmintrin.h>
+            int param;
+            int main () {
+            __m128i a = _mm_set1_epi32 (param), b = _mm_set1_epi32 (param + 1), c;
+            c = _mm_max_epu32(a, b);
+            return _mm_cvtsi128_si32(c);
+            }
+   '''
+  compiler = meson.get_compiler('c')
+  result = compiler.compiles(code, args: '-msse4.1', name : 'sse41 check')
+
+  if result == true
+    pre_args += '-DUSE_SSE41'
+    with_sse41 = true
+    sse41_args = ['-msse4.1']
+
+    # GCC on x86 (not x86_64) with -msse* assumes a 16 byte aligned stack, but
+    # that's not guaranteed
+    if host_machine.cpu_family() == 'x86'
+      sse41_args += '-mstackrealign'
+    endif
   endif
-else
-  with_sse41 = false
-  sse41_args = []
 endif
 
 # Check for GCC style atomics
-- 
2.14.4