[PATCH v3 1/2] rs6000: Add support for _mm_minpos_epu16

[Paul A. Clarke]

Add a naive implementation of the subject x86 intrinsic to
ease porting.

2021-07-15  Paul A. Clarke  <pc@us.ibm.com>

gcc
        * config/rs6000/smmintrin.h (_mm_minpos_epu16): New.
---
v3: Minor formatting changes per review from Bill.
v2: Minor formatting changes per review from Segher.

 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 16fd34d836ff..6a010fdbb96f 100644
--- a/gcc/config/rs6000/smmintrin.h
+++ b/gcc/config/rs6000/smmintrin.h
@@ -172,4 +172,31 @@ _mm_test_mix_ones_zeros (__m128i __A, __m128i __mask)
   return any_ones * any_zeros;
 }
 
+/* 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
-- 
2.27.0