s390: Fix up *vec_cmpgt{,u}<mode><mode>_nocc_emu splitters [PR118696]

The following testcase is miscompiled on s390x-linux with e.g. -march=z13
(both -O0 and -O2) starting with r15-7053.
The problem is in the splitters which emulate TImode/V1TImode GT and GTU
comparisons.
For GT we want to do
(ior (gt (hi op1) (hi op2))
     (and (eq (hi op1) (hi op2)) (gtu (lo op1) (lo op2))))
and for GTU similarly except for gtu instead of gt in there.
Now, the splitter emulation is using V2DImode comparisons where on s390x
the hi part is in the first element of the vector, lo part in the second,
and for the gtu case it swaps the elements of the vector.
So, we get the right result in the first element of the result vector.
But vrepg was then broadcasting the second element of the result vector
rather than the first, and the value of the second element of the vector
is instead
(ior (gt (lo op1) (lo op2))
     (and (eq (lo op1) (lo op2)) (gtu (hi op1) (hi op2))))
so something not really usable for the emulated comparison.

The following patch fixes that.  The testcase tries to test behavior of
double-word smin/smax/umin/umax with various cases of the halves of both
operands (one that is sometimes EQ, sometimes GT, sometimes LT, sometimes
GTU, sometimes LTU).

2025-01-30  Jakub Jelinek  <jakub@redhat.com>
	    Stefan Schulze Frielinghaus  <stefansf@gcc.gnu.org>

	PR target/118696
	* config/s390/vector.md (*vec_cmpgt<mode><mode>_nocc_emu,
	*vec_cmpgtu<mode><mode>_nocc_emu): Duplicate the first rather than
	second V2DImode element.

	* gcc.dg/pr118696.c: New test.
	* gcc.target/s390/vector/pr118696.c: New test.
	* gcc.target/s390/vector/vec-abs-emu.c: Expect vrepg with 0 as last
	operand rather than 1.
	* gcc.target/s390/vector/vec-max-emu.c: Likewise.
	* gcc.target/s390/vector/vec-min-emu.c: Likewise.

6 files changed, 141 insertions, 5 deletions

diff --git a/gcc/config/s390/vector.md b/gcc/config/s390/vector.md
index 547e6a2..e29255f 100644
--- a/gcc/config/s390/vector.md
+++ b/gcc/config/s390/vector.md
@@ -2166,7 +2166,7 @@
 	(vec_duplicate:V2DI
 	 (vec_select:DI
 	  (match_dup 4)
-	  (parallel [(const_int 1)]))))
+	  (parallel [(const_int 0)]))))
    (set (match_dup 0)
 	(subreg:<MODE> (match_dup 4) 0))]
 {
@@ -2198,7 +2198,7 @@
 	(vec_duplicate:V2DI
 	 (vec_select:DI
 	  (match_dup 4)
-	  (parallel [(const_int 1)]))))
+	  (parallel [(const_int 0)]))))
    (set (match_dup 0)
 	(subreg:<MODE> (match_dup 4) 0))]
 {
diff --git a/gcc/testsuite/gcc.dg/pr118696.c b/gcc/testsuite/gcc.dg/pr118696.c
new file mode 100644
index 0000000..092af6f
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/pr118696.c
@@ -0,0 +1,131 @@
+/* PR target/118696 */
+/* { dg-do run } */
+/* { dg-options "-O2" } */
+
+#if __CHAR_BIT__ == 8
+#if __SIZEOF_INT128__ == 16 && __SIZEOF_LONG_LONG__ == 8
+#define D __int128
+#define S long long
+#define M 0x8000000000000000ULL
+#define C 64
+#elif __SIZEOF_LONG_LONG__ == 8 && __SIZEOF_INT__ == 4
+#define D long long
+#define S int
+#define M 0x80000000U
+#define C 32
+#endif
+#endif
+
+#ifdef D
+static inline D
+combine (unsigned S x, unsigned S y)
+{
+  return (unsigned D) x << C | y;
+}
+
+__attribute__((noipa)) D
+smin (D x, D y)
+{
+  return x < y ? x : y;
+}
+
+__attribute__((noipa)) D
+smax (D x, D y)
+{
+  return x > y ? x : y;
+}
+
+__attribute__((noipa)) unsigned D
+umin (unsigned D x, unsigned D y)
+{
+  return x < y ? x : y;
+}
+
+__attribute__((noipa)) unsigned D
+umax (unsigned D x, unsigned D y)
+{
+  return x > y ? x : y;
+}
+#endif
+
+int
+main ()
+{
+#ifdef D
+  unsigned S vals[] = {
+    0, 12, 42, M, M | 12, M | 42
+  };
+  unsigned char expected[] = {
+    4,3,3,3,3,3,3,3,3,3,3,3,3,3,3,3,3,3,2,2,2,2,2,2,2,2,2,2,2,2,2,2,
+    2,2,2,2,0,4,3,3,3,3,3,3,3,3,3,3,3,3,3,3,3,3,2,2,2,2,2,2,2,2,2,2,
+    2,2,2,2,2,2,2,2,0,0,4,3,3,3,3,3,3,3,3,3,3,3,3,3,3,3,2,2,2,2,2,2,
+    2,2,2,2,2,2,2,2,2,2,2,2,0,0,0,4,3,3,3,3,3,3,3,3,3,3,3,3,3,3,2,2,
+    2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,0,0,0,0,4,3,3,3,3,3,3,3,3,3,3,3,
+    3,3,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,0,0,0,0,0,4,3,3,3,3,3,3,
+    3,3,3,3,3,3,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,0,0,0,0,0,0,4,3,
+    3,3,3,3,3,3,3,3,3,3,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,0,0,0,0,
+    0,0,0,4,3,3,3,3,3,3,3,3,3,3,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,
+    0,0,0,0,0,0,0,0,4,3,3,3,3,3,3,3,3,3,2,2,2,2,2,2,2,2,2,2,2,2,2,2,
+    2,2,2,2,0,0,0,0,0,0,0,0,0,4,3,3,3,3,3,3,3,3,2,2,2,2,2,2,2,2,2,2,
+    2,2,2,2,2,2,2,2,0,0,0,0,0,0,0,0,0,0,4,3,3,3,3,3,3,3,2,2,2,2,2,2,
+    2,2,2,2,2,2,2,2,2,2,2,2,0,0,0,0,0,0,0,0,0,0,0,4,3,3,3,3,3,3,2,2,
+    2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,0,0,0,0,0,0,0,0,0,0,0,0,4,3,3,3,
+    3,3,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,0,0,0,0,0,0,0,0,0,0,0,0,
+    0,4,3,3,3,3,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,0,0,0,0,0,0,0,0,
+    0,0,0,0,0,0,4,3,3,3,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,0,0,0,0,
+    0,0,0,0,0,0,0,0,0,0,0,4,3,3,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,
+    0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,4,3,2,2,2,2,2,2,2,2,2,2,2,2,2,2,
+    2,2,2,2,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,4,2,2,2,2,2,2,2,2,2,2,
+    2,2,2,2,2,2,2,2,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,4,3,3,3,3,3,
+    3,3,3,3,3,3,3,3,3,3,3,3,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,0,4,
+    3,3,3,3,3,3,3,3,3,3,3,3,3,3,3,3,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,
+    1,1,0,0,4,3,3,3,3,3,3,3,3,3,3,3,3,3,3,3,1,1,1,1,1,1,1,1,1,1,1,1,
+    1,1,1,1,1,1,0,0,0,4,3,3,3,3,3,3,3,3,3,3,3,3,3,3,1,1,1,1,1,1,1,1,
+    1,1,1,1,1,1,1,1,1,1,0,0,0,0,4,3,3,3,3,3,3,3,3,3,3,3,3,3,1,1,1,1,
+    1,1,1,1,1,1,1,1,1,1,1,1,1,1,0,0,0,0,0,4,3,3,3,3,3,3,3,3,3,3,3,3,
+    1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,0,0,0,0,0,0,4,3,3,3,3,3,3,3,
+    3,3,3,3,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,0,0,0,0,0,0,0,4,3,3,
+    3,3,3,3,3,3,3,3,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,0,0,0,0,0,0,
+    0,0,4,3,3,3,3,3,3,3,3,3,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,0,0,
+    0,0,0,0,0,0,0,4,3,3,3,3,3,3,3,3,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,
+    1,1,0,0,0,0,0,0,0,0,0,0,4,3,3,3,3,3,3,3,1,1,1,1,1,1,1,1,1,1,1,1,
+    1,1,1,1,1,1,0,0,0,0,0,0,0,0,0,0,0,4,3,3,3,3,3,3,1,1,1,1,1,1,1,1,
+    1,1,1,1,1,1,1,1,1,1,0,0,0,0,0,0,0,0,0,0,0,0,4,3,3,3,3,3,1,1,1,1,
+    1,1,1,1,1,1,1,1,1,1,1,1,1,1,0,0,0,0,0,0,0,0,0,0,0,0,0,4,3,3,3,3,
+    1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
+    4,3,3,3,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,0,0,0,0,0,0,0,0,0,0,
+    0,0,0,0,0,4,3,3,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,0,0,0,0,0,0,
+    0,0,0,0,0,0,0,0,0,0,4,3,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,0,0,
+    0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,4
+  };
+  int m = 0;
+  for (int i = 0; i < 6; ++i)
+    for (int j = 0; j < 6; ++j)
+      for (int k = 0; k < 6; ++k)
+	for (int l = 0; l < 6; ++l)
+	  {
+	    D a = combine (vals[i], vals[j]);
+	    D b = combine (vals[k], vals[l]);
+	    int r = 0;
+	    r |= (smin (a, b) == a) * 1;
+	    r |= (smin (a, b) == b) * 2;
+	    r |= (smax (a, b) == a) * 4;
+	    r |= (smax (a, b) == b) * 8;
+	    r |= (umin (a, b) == a) * 16;
+	    r |= (umin (a, b) == b) * 32;
+	    r |= (umax (a, b) == a) * 64;
+	    r |= (umax (a, b) == b) * 128;
+	    switch (r)
+	      {
+	      case 102: r = 0; break;
+	      case 105: r = 1; break;
+	      case 150: r = 2; break;
+	      case 153: r = 3; break;
+	      case 255: r = 4; break;
+	      default: __builtin_abort ();
+	      }
+	    if (r != expected[m++])
+	      __builtin_abort ();
+	  }
+#endif
+}
diff --git a/gcc/testsuite/gcc.target/s390/vector/pr118696.c b/gcc/testsuite/gcc.target/s390/vector/pr118696.c
new file mode 100644
index 0000000..1f67bf5
--- /dev/null
+++ b/gcc/testsuite/gcc.target/s390/vector/pr118696.c
@@ -0,0 +1,5 @@
+/* PR target/118696 */
+/* { dg-do run } */
+/* { dg-options "-O2 -mzarch -march=z13" } */
+
+#include "../../../gcc.dg/pr118696.c"
diff --git a/gcc/testsuite/gcc.target/s390/vector/vec-abs-emu.c b/gcc/testsuite/gcc.target/s390/vector/vec-abs-emu.c
index 8c1038a..e0dd222 100644
--- a/gcc/testsuite/gcc.target/s390/vector/vec-abs-emu.c
+++ b/gcc/testsuite/gcc.target/s390/vector/vec-abs-emu.c
@@ -18,7 +18,7 @@ typedef __attribute__ ((vector_size (16))) signed __int128 v1ti;
 **	vchg	%v[0-9]+,%v[0-9]+,%v[0-9]+
 **	vn	%v[0-9]+,%v[0-9]+,%v[0-9]+
 **	vo	%v[0-9]+,%v[0-9]+,%v[0-9]+
-**	vrepg	%v[0-9]+,%v[0-9]+,1
+**	vrepg	%v[0-9]+,%v[0-9]+,0
 **	vsq	%v[0-9]+,%v[0-9]+,%v[0-9]+
 **	vsel	%v[0-9]+,%v[0-9]+,%v[0-9]+,%v[0-9]+
 **	br	%r14
diff --git a/gcc/testsuite/gcc.target/s390/vector/vec-max-emu.c b/gcc/testsuite/gcc.target/s390/vector/vec-max-emu.c
index 1c4451b..12c7e76 100644
--- a/gcc/testsuite/gcc.target/s390/vector/vec-max-emu.c
+++ b/gcc/testsuite/gcc.target/s390/vector/vec-max-emu.c
@@ -17,7 +17,7 @@ typedef __attribute__ ((vector_size (16))) signed __int128 v1ti;
 **	vchg	%v[0-9]+,%v[0-9]+,%v[0-9]+
 **	vn	%v[0-9]+,%v[0-9]+,%v[0-9]+
 **	vo	%v[0-9]+,%v[0-9]+,%v[0-9]+
-**	vrepg	%v[0-9]+,%v[0-9]+,1
+**	vrepg	%v[0-9]+,%v[0-9]+,0
 **	vsel	%v[0-9]+,%v[0-9]+,%v[0-9]+,%v[0-9]+
 **	br	%r14
 */
diff --git a/gcc/testsuite/gcc.target/s390/vector/vec-min-emu.c b/gcc/testsuite/gcc.target/s390/vector/vec-min-emu.c
index 89f4dff..a9bcba3 100644
--- a/gcc/testsuite/gcc.target/s390/vector/vec-min-emu.c
+++ b/gcc/testsuite/gcc.target/s390/vector/vec-min-emu.c
@@ -17,7 +17,7 @@ typedef __attribute__ ((vector_size (16))) signed __int128 v1ti;
 **	vchg	%v[0-9]+,%v[0-9]+,%v[0-9]+
 **	vn	%v[0-9]+,%v[0-9]+,%v[0-9]+
 **	vo	%v[0-9]+,%v[0-9]+,%v[0-9]+
-**	vrepg	%v[0-9]+,%v[0-9]+,1
+**	vrepg	%v[0-9]+,%v[0-9]+,0
 **	vsel	%v[0-9]+,%v[0-9]+,%v[0-9]+,%v[0-9]+
 **	br	%r14
 */