[gcc r14-12661] tree-optimization/124555 - guard abs patterns for vector support

[Richard Biener]

https://gcc.gnu.org/g:8ca429aeafc2afc569900a00e77068c5e39985cb

commit r14-12661-g8ca429aeafc2afc569900a00e77068c5e39985cb
Author: Richard Biener <rguenther@suse.de>
Date:   Wed Mar 18 10:15:00 2026 +0100

    tree-optimization/124555 - guard abs patterns for vector support
    
    The following adds missing vector support checks to abs producing
    match.pd patterns.  The g++.dg/absvect.C shows that we previously
    then lowered this to non-vector unless you add -msse4 on x86_64
    at least.
    
            PR tree-optimization/124555
            * match.pd ((A - B) >=/> 0 ? (A - B) : (B - A) -> abs (A - B)):
            Guard the vector case with target_supports_op_p checks.
            ((A - B) <=/< 0 ? (A - B) : (B - A) -> -abs (A - B)): Likewise.
            ((type)A >=/> 0 ? A : -A -> abs (A)): Likewise.
            ((type)A <=/< 0 ? A : -A -> -abs (A)): Likewise.
    
            * gcc.dg/torture/pr124555.c: New testcase.
            * g++.dg/absvect.C: Restrict dump scan to x86-64 and force
            -msse4 there.
    
    (cherry picked from commit c97e6d7be7d51cd812b2acde680cd9704bae3c70)

Diff:
---
 gcc/match.pd                            | 17 +++++++++++++----
 gcc/testsuite/g++.dg/absvect.C          | 13 +++++++++++++
 gcc/testsuite/gcc.dg/torture/pr124555.c | 25 +++++++++++++++++++++++++
 3 files changed, 51 insertions(+), 4 deletions(-)

diff --git a/gcc/match.pd b/gcc/match.pd
index 2d19f6472be5..d1b11483520e 100644
--- a/gcc/match.pd
+++ b/gcc/match.pd
@@ -5960,7 +5960,9 @@ DEFINE_INT_AND_FLOAT_ROUND_FN (RINT)
    (cnd (cmp @0 zerop) @1 (negate @1))
     (if (!HONOR_SIGNED_ZEROS (TREE_TYPE(@0))
 	 && !TYPE_UNSIGNED (TREE_TYPE(@0))
-	 && bitwise_equal_p (@0, @1))
+	 && bitwise_equal_p (@0, @1)
+	 && (!VECTOR_TYPE_P (type)
+	     || target_supports_op_p (type, ABS_EXPR, optab_vector)))
      (if (TYPE_UNSIGNED (type))
       (absu:type @0)
       (abs @0)))))
@@ -5970,7 +5972,9 @@ DEFINE_INT_AND_FLOAT_ROUND_FN (RINT)
    (cnd (cmp @0 zerop) @1 (negate @1))
     (if (!HONOR_SIGNED_ZEROS (TREE_TYPE(@0))
 	 && !TYPE_UNSIGNED (TREE_TYPE(@0))
-	 && bitwise_equal_p (@0, @1))
+	 && bitwise_equal_p (@0, @1)
+	 && (!VECTOR_TYPE_P (type)
+	     || target_supports_op_p (type, ABS_EXPR, optab_vector)))
      (if ((ANY_INTEGRAL_TYPE_P (TREE_TYPE (@0))
 	   && !TYPE_OVERFLOW_WRAPS (TREE_TYPE (@0)))
 	  || TYPE_UNSIGNED (type))
@@ -6006,7 +6010,9 @@ DEFINE_INT_AND_FLOAT_ROUND_FN (RINT)
   (simplify
    (cnd (cmp (minus@0 @1 @2) zerop) @0 (minus @2 @1))
    (if (!HONOR_SIGNED_ZEROS (type)
-	&& !TYPE_UNSIGNED (type))
+	&& !TYPE_UNSIGNED (type)
+	&& (!VECTOR_TYPE_P (type)
+	    || target_supports_op_p (type, ABS_EXPR, optab_vector)))
     (abs @0))))
  /* (A - B) <=/< 0 ? (A - B) : (B - A)    same as -abs (A - B) */
  (for cmp (le lt)
@@ -6015,7 +6021,10 @@ DEFINE_INT_AND_FLOAT_ROUND_FN (RINT)
    (if (!HONOR_SIGNED_ZEROS (type)
 	&& !TYPE_UNSIGNED (type))
     (if (ANY_INTEGRAL_TYPE_P (type)
-	 && !TYPE_OVERFLOW_WRAPS (type))
+	 && !TYPE_OVERFLOW_WRAPS (type)
+	 && (!VECTOR_TYPE_P (type)
+	     || (target_supports_op_p (type, ABS_EXPR, optab_vector)
+		 && target_supports_op_p (type, NEGATE_EXPR, optab_vector))))
      (with {
         tree utype = unsigned_type_for (type);
       }
diff --git a/gcc/testsuite/g++.dg/absvect.C b/gcc/testsuite/g++.dg/absvect.C
new file mode 100644
index 000000000000..d28ea846d74d
--- /dev/null
+++ b/gcc/testsuite/g++.dg/absvect.C
@@ -0,0 +1,13 @@
+/* { dg-do compile } */
+/* { dg-options "-Ofast -fdump-tree-phiopt1" } */
+/* { dg-additional-options "-msse4" { target { x86_64-*-* i?86-*-* } } } */
+/* { dg-final { scan-tree-dump-times " = ABS_EXPR <x_\[0-9]*\\\(D\\\)>;" 1 "phiopt1" { target { x86_64-*-* i?86-*-* } } } } */
+
+typedef int v2si __attribute__ ((vector_size (2 * sizeof(int))));
+typedef short v2hi __attribute__ ((vector_size (2 * sizeof(short))));
+
+v2hi  absvect1 (v2hi x, int i) {
+    v2hi neg = -x;
+    return (x > 0) ? x : neg;
+}
+
diff --git a/gcc/testsuite/gcc.dg/torture/pr124555.c b/gcc/testsuite/gcc.dg/torture/pr124555.c
new file mode 100644
index 000000000000..668ad7b904ba
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/torture/pr124555.c
@@ -0,0 +1,25 @@
+/* { dg-additional-options "-fwrapv" } */
+
+int vsad8_c_y;
+char *vsad8_c_s1, *vsad8_c_s2;
+long vsad8_c_stride;
+int vsad8_c()
+{
+  int score, x;
+  for (; vsad8_c_y; vsad8_c_y++)
+    {
+      x = 0;
+      for (; x < 8; x++)
+	score += (vsad8_c_s1[x] - vsad8_c_s2[x] - vsad8_c_s1[x + vsad8_c_stride]
+	    + vsad8_c_s2[x + vsad8_c_stride]) >= 0
+	    ? vsad8_c_s1[x] - vsad8_c_s2[x] -
+	    vsad8_c_s1[x + vsad8_c_stride] +
+	    vsad8_c_s2[x + vsad8_c_stride]
+	    : -(vsad8_c_s1[x] - vsad8_c_s2[x] -
+		vsad8_c_s1[x + vsad8_c_stride] +
+		vsad8_c_s2[x + vsad8_c_stride]);
+      vsad8_c_s1 += vsad8_c_stride;
+      vsad8_c_s2 += vsad8_c_stride;
+    }
+  return score;
+}