[gcc r12-2705] rs6000: Add support for _mm_minpos_epu16

[Paul Clarke <pc@gcc.gnu.org>]

https://gcc.gnu.org/g:eaa93a0f3d9f67c8cbc1dc849ea6feba432ff412

commit r12-2705-geaa93a0f3d9f67c8cbc1dc849ea6feba432ff412
Author: Paul A. Clarke <pc@us.ibm.com>
Date:   Mon Feb 22 19:13:28 2021 -0600

    rs6000: Add support for _mm_minpos_epu16
    
    Add a naive implementation of the subject x86 intrinsic to
    ease porting.
    
    2021-08-03  Paul A. Clarke  <pc@us.ibm.com>
    
    gcc
            * config/rs6000/smmintrin.h (_mm_minpos_epu16): New.

Diff:
---
 gcc/config/rs6000/smmintrin.h | 27 +++++++++++++++++++++++++++
 1 file changed, 27 insertions(+)

diff --git a/gcc/config/rs6000/smmintrin.h b/gcc/config/rs6000/smmintrin.h
index 0145b9229a6..3767a67eada 100644
--- a/gcc/config/rs6000/smmintrin.h
+++ b/gcc/config/rs6000/smmintrin.h
@@ -296,4 +296,31 @@ _mm_floor_ss (__m128 __A, __m128 __B)
   return __r;
 }
 
+/* Return horizontal packed word minimum and its index in bits [15:0]
+   and bits [18:16] respectively.  */
+__inline __m128i
+__attribute__ ((__gnu_inline__, __always_inline__, __artificial__))
+_mm_minpos_epu16 (__m128i __A)
+{
+  union __u
+    {
+      __m128i __m;
+      __v8hu __uh;
+    };
+  union __u __u = { .__m = __A }, __r = { .__m = {0} };
+  unsigned short __ridx = 0;
+  unsigned short __rmin = __u.__uh[__ridx];
+  for (unsigned long __i = 1; __i < 8; __i++)
+    {
+      if (__u.__uh[__i] < __rmin)
+	{
+	  __rmin = __u.__uh[__i];
+	  __ridx = __i;
+	}
+    }
+  __r.__uh[0] = __rmin;
+  __r.__uh[1] = __ridx;
+  return __r.__m;
+}
+
 #endif