configure.ac: Fix the test for compiling half-floating point code.

_mm_cvtph_ps is implicitly defined if the compiler does not support
it. So, we need to store its return value in a variable so that
the test fails to type check when the function is implicitly defined
to return an int.

diff --git a/configure.ac b/configure.ac
index 28e9af0b89e616a90ee83327e6cce6b02d0aa305..e2ab5f7de6ced8f41bde064b16e65a4f2d4ce4c8 100644 (file)
--- a/configure.ac
+++ b/configure.ac
@@ -390,7 +390,7 @@ if test "x$enable_mmx" = xyes; then
 
         CFLAGS="$CFLAGS $sse_flag $f16c_flag"
 
-        AC_COMPILE_IFELSE([AC_LANG_PROGRAM([#include <immintrin.h>],[_mm_cvtph_ps ((__m128i)_mm_setzero_ps());])],
+        AC_COMPILE_IFELSE([AC_LANG_PROGRAM([#include <immintrin.h>],[__m128 val = _mm_cvtph_ps ((__m128i)_mm_setzero_ps());])],
           AC_DEFINE(USE_F16C, 1, [Define to 1 if f16c intrinsics are available.])
           AC_MSG_RESULT(yes)
         ,