write saxpy_haswell kernel using C intrinsics and don't disallow inlining

the intrinsics version of saxpy is more readable than the inline asm version,
and in the intrinsics version there's no reason anymore to ban inlining
(since the compiler has full visibility now) which gives a mid single digits
improvement in performance

kernel/x86_64/saxpy_microk_haswell-2.c

@@ -25,54 +25,43 @@ OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE
 USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 *****************************************************************************/
 
-#define HAVE_KERNEL_16 1
-static void saxpy_kernel_16( BLASLONG n, FLOAT *x, FLOAT *y , FLOAT *alpha) __attribute__ ((noinline));
 
-static void saxpy_kernel_16( BLASLONG n, FLOAT *x, FLOAT *y, FLOAT *alpha)
-{
+#ifndef __AVX512CD__
+#pragma GCC target("avx2,fma")
+#endif
 
+#ifdef __AVX2__
 
-	BLASLONG register i = 0;
+#define HAVE_KERNEL_16 1
 
-	__asm__  __volatile__
-	(
-	"vbroadcastss		(%[alpha]), %%ymm0		\n\t"  // alpha	
+#include <immintrin.h>
+
+static void saxpy_kernel_16( BLASLONG n, FLOAT *x, FLOAT *y, FLOAT *alpha)
+{
+	BLASLONG i = 0;
 
-	".p2align 4				         	\n\t"
-	"1:				            		\n\t"
+	__m256 __alpha;
 
-        "vmovups                  (%[y],%[i],4), %%ymm12         \n\t"  // 8 * y
-        "vmovups                32(%[y],%[i],4), %%ymm13         \n\t"  // 8 * y
-        "vmovups                64(%[y],%[i],4), %%ymm14         \n\t"  // 8 * y
-        "vmovups                96(%[y],%[i],4), %%ymm15         \n\t"  // 8 * y
-	"vfmadd231ps       (%[x],%[i],4), %%ymm0  , %%ymm12  	     \n\t"   // y += alpha * x
-	"vfmadd231ps     32(%[x],%[i],4), %%ymm0  , %%ymm13  	     \n\t"   // y += alpha * x
-	"vfmadd231ps     64(%[x],%[i],4), %%ymm0  , %%ymm14  	     \n\t"   // y += alpha * x
-	"vfmadd231ps     96(%[x],%[i],4), %%ymm0  , %%ymm15  	     \n\t"   // y += alpha * x
-	"vmovups	%%ymm12,   (%[y],%[i],4)		     \n\t"
-	"vmovups	%%ymm13, 32(%[y],%[i],4)		     \n\t"
-	"vmovups	%%ymm14, 64(%[y],%[i],4)		     \n\t"
-	"vmovups	%%ymm15, 96(%[y],%[i],4)		     \n\t"
+	__alpha =  _mm256_broadcastss_ps(_mm_load_ss(alpha));
 
-	"addq		$32, %[i]  	 	             \n\t"
-	"subq	        $32, %[n]		             \n\t"		
-	"jnz		1b		             \n\t"
-	"vzeroupper				     \n\t"
+	for (; i < n; i+= 32) {
+		__m256 y0, y8, y16, y24;
 
-	:
-        : 
-          [i] "r" (i),	// 0	
-	  [n] "r" (n),  // 1
-          [x] "r" (x),  // 2
-          [y] "r" (y),  // 3
-          [alpha] "r" (alpha)   // 4
-	: "cc", 
-	  "%xmm0", 
-	  "%xmm8", "%xmm9", "%xmm10", "%xmm11", 
-	  "%xmm12", "%xmm13", "%xmm14", "%xmm15",
-	  "memory"
-	);
+		y0  = _mm256_loadu_ps(&y[i +  0]);
+		y8  = _mm256_loadu_ps(&y[i +  8]);
+		y16 = _mm256_loadu_ps(&y[i + 16]);
+		y24 = _mm256_loadu_ps(&y[i + 24]);
 
-} 
+		y0  += __alpha * _mm256_loadu_ps(&x[i +  0]);
+		y8  += __alpha * _mm256_loadu_ps(&x[i +  8]);
+		y16 += __alpha * _mm256_loadu_ps(&x[i + 16]);
+		y24 += __alpha * _mm256_loadu_ps(&x[i + 24]);
 
+		_mm256_storeu_ps(&y[i +  0], y0);
+		_mm256_storeu_ps(&y[i +  8], y8);
+		_mm256_storeu_ps(&y[i + 16], y16);
+		_mm256_storeu_ps(&y[i + 24], y24);
+	}
+}
+#endif