From d24b415f3e2753a588759d028b811e1ce38fea6c Mon Sep 17 00:00:00 2001 From: Andrea Canciani Date: Sun, 11 Oct 2015 09:45:57 +0200 Subject: mmx: Improve detection of support for "K" constraint Older versions of clang emitted an error on the "K" constraint, but at least since version 3.7 it is supported. Just like gcc, this constraint is only allowed for constants, but apparently clang requires them to be known before inlining. Using the macro definition _mm_shuffle_pi16(A, N) ensures that the "K" constraint is always applied to a literal constant, independently from the compiler optimizations and allows building pixman-mmx on modern clang. Reviewed-by: Matt Turner Signed-off-by: Andrea Canciani --- configure.ac | 22 +++++++++++++++++----- pixman/pixman-mmx.c | 17 +---------------- 2 files changed, 18 insertions(+), 21 deletions(-) diff --git a/configure.ac b/configure.ac index 2178126..3a66909 100644 --- a/configure.ac +++ b/configure.ac @@ -347,15 +347,27 @@ AC_COMPILE_IFELSE([AC_LANG_SOURCE([[ #error "Need GCC >= 3.4 for MMX intrinsics" #endif #include +#include + +/* Check support for block expressions */ +#define _mm_shuffle_pi16(A, N) \ + ({ \ + __m64 ret; \ + \ + /* Some versions of clang will choke on K */ \ + asm ("pshufw %2, %1, %0\n\t" \ + : "=y" (ret) \ + : "y" (A), "K" ((const int8_t)N) \ + ); \ + \ + ret; \ + }) + int main () { __m64 v = _mm_cvtsi32_si64 (1); __m64 w; - /* Some versions of clang will choke on K */ - asm ("pshufw %2, %1, %0\n\t" - : "=y" (w) - : "y" (v), "K" (5) - ); + w = _mm_shuffle_pi16(v, 5); /* Some versions of clang will choke on this */ asm ("pmulhuw %1, %0\n\t" diff --git a/pixman/pixman-mmx.c b/pixman/pixman-mmx.c index 05c48a4..dec3974 100644 --- a/pixman/pixman-mmx.c +++ b/pixman/pixman-mmx.c @@ -89,21 +89,7 @@ _mm_mulhi_pu16 (__m64 __A, __m64 __B) return __A; } -# ifdef __OPTIMIZE__ -extern __inline __m64 __attribute__((__gnu_inline__, __always_inline__, __artificial__)) -_mm_shuffle_pi16 (__m64 __A, int8_t const __N) -{ - __m64 ret; - - asm ("pshufw %2, %1, %0\n\t" - : "=y" (ret) - : "y" (__A), "K" (__N) - ); - - return ret; -} -# else -# define _mm_shuffle_pi16(A, N) \ +# define _mm_shuffle_pi16(A, N) \ ({ \ __m64 ret; \ \ @@ -114,7 +100,6 @@ _mm_shuffle_pi16 (__m64 __A, int8_t const __N) \ ret; \ }) -# endif # endif #endif -- cgit v1.2.3