rs6000: Add test for _mm_minpos_epu16

Copy the test for _mm_minpos_epu16 from
gcc/testsuite/gcc.target/i386/sse4_1-phminposuw.c, with
a few adjustments:

- Adjust the dejagnu directives for powerpc platform.
- Make the data not be monotonically increasing,
  such that some of the returned values are not
  always the first value (index 0).
- Create a list of input data testing various scenarios
  including more than one minimum value and different
  orders and indices of the minimum value.
- Fix a masking issue where the index was being truncated
  to 2 bits instead of 3 bits, which wasn't found because
  all of the returned indices were 0 with the original
  generated data.
- Support big-endian.

2021-08-03  Paul A. Clarke  <pc@us.ibm.com>

gcc/testsuite
	* gcc.target/powerpc/sse4_1-phminposuw.c: Copy from
	gcc/testsuite/gcc.target/i386, adjust dg directives to suit,
	make more robust.

1 files changed, 68 insertions, 0 deletions

diff --git a/gcc/testsuite/gcc.target/powerpc/sse4_1-phminposuw.c b/gcc/testsuite/gcc.target/powerpc/sse4_1-phminposuw.c
new file mode 100644
index 0000000..146df24
--- /dev/null
+++ b/gcc/testsuite/gcc.target/powerpc/sse4_1-phminposuw.c
@@ -0,0 +1,68 @@
+/* { dg-do run } */
+/* { dg-options "-O2 -mvsx -Wno-psabi" } */
+/* { dg-require-effective-target powerpc_vsx_ok } */
+
+#define NO_WARN_X86_INTRINSICS 1
+#ifndef CHECK_H
+#define CHECK_H "sse4_1-check.h"
+#endif
+
+#ifndef TEST
+#define TEST sse4_1_test
+#endif
+
+#include CHECK_H
+
+#include <smmintrin.h>
+
+#define DIM(a) (sizeof (a) / sizeof (a)[0])
+
+static void
+TEST (void)
+{
+  union
+    {
+      __m128i x;
+      unsigned short s[8];
+    } src[] =
+    {
+      { .s = { 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000 } },
+      { .s = { 0x0000, 0xffff, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000 } },
+      { .s = { 0xffff, 0xffff, 0x0000, 0xffff, 0xffff, 0xffff, 0x0000, 0xffff } },
+      { .s = { 0x0001, 0x0002, 0x0003, 0x0004, 0x0005, 0x0006, 0x0007, 0x0008 } },
+      { .s = { 0x0008, 0x0007, 0x0006, 0x0005, 0x0004, 0x0003, 0x0002, 0x0001 } },
+      { .s = { 0xfff4, 0xfff3, 0xfff2, 0xfff1, 0xfff3, 0xfff1, 0xfff2, 0xfff3 } }
+    };
+  unsigned short minVal[DIM (src)];
+  int minInd[DIM (src)];
+  unsigned short minValScalar, minIndScalar;
+  int i, j;
+  union
+    {
+      int si;
+      unsigned short s[2];
+    } res;
+
+  for (i = 0; i < DIM (src); i++)
+    {
+      res.si = _mm_cvtsi128_si32 (_mm_minpos_epu16 (src[i].x));
+      minVal[i] = res.s[0];
+      minInd[i] = res.s[1] & 0b111;
+    }
+
+  for (i = 0; i < DIM (src); i++)
+    {
+      minValScalar = src[i].s[0];
+      minIndScalar = 0;
+
+      for (j = 1; j < 8; j++)
+	if (minValScalar > src[i].s[j])
+	  {
+	    minValScalar = src[i].s[j];
+	    minIndScalar = j;
+	  }
+
+      if (minValScalar != minVal[i] && minIndScalar != minInd[i])
+	abort ();
+    }
+}