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[PUSHED/13,1/4] vec-lowering: Fix ABSU lowering [PR111285]

Message ID 20250415043850.1180312-2-quic_apinski@quicinc.com
State New
Headers
Series Backported patches to gcc 13 |

Commit Message

Andrew Pinski April 15, 2025, 4:38 a.m. UTC 
  ABSU_EXPR lowering incorrectly used the resulting type
for the new expression but in the case of ABSU the resulting
type is an unsigned type and with ABSU is folded away. The fix
is to use a signed type for the expression instead.

Bootstrapped and tested on x86_64-linux-gnu.

	PR middle-end/111285

gcc/ChangeLog:

	* tree-vect-generic.cc (do_unop): Use a signed type for the
	operand if the operation was ABSU_EXPR.

gcc/testsuite/ChangeLog:

	* g++.dg/torture/vect-absu-1.C: New test.

Signed-off-by: Andrew Pinski <quic_apinski@quicinc.com>
(cherry picked from commit ad0084337e901ddaedd48c14e7a5dad9fc2a093e)
(cherry picked from commit 8ee9d7b26342b96f462ebafa1304a26d83b4e833)
---
 gcc/testsuite/g++.dg/torture/vect-absu-1.C | 29 ++++++++++++++++++++++
 gcc/tree-vect-generic.cc                   | 10 +++++++-
 2 files changed, 38 insertions(+), 1 deletion(-)
 create mode 100644 gcc/testsuite/g++.dg/torture/vect-absu-1.C
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Patch

diff --git a/gcc/testsuite/g++.dg/torture/vect-absu-1.C b/gcc/testsuite/g++.dg/torture/vect-absu-1.C
new file mode 100644
index 00000000000..0b2035f638f
--- /dev/null
+++ b/gcc/testsuite/g++.dg/torture/vect-absu-1.C
@@ -0,0 +1,29 @@ 
+// { dg-do run }
+// PR middle-end/111285
+
+// The lowering of vect absu was done incorrectly
+
+#define vect1 __attribute__((vector_size(sizeof(int))))
+
+#define negabs(a) a < 0 ? a : -a
+
+__attribute__((noinline))
+int s(int a)
+{
+  return negabs(a);
+}
+__attribute__((noinline))
+vect1 int v(vect1 int a)
+{
+  return negabs(a);
+}
+
+int main(void)
+{
+        for(int i = -10; i < 10; i++)
+        {
+          vect1 int t = {i};
+          if (v(t)[0] != s(i))
+            __builtin_abort();
+        }
+}
diff --git a/gcc/tree-vect-generic.cc b/gcc/tree-vect-generic.cc
index 6e74bf05be2..0b85a54a4ce 100644
--- a/gcc/tree-vect-generic.cc
+++ b/gcc/tree-vect-generic.cc
@@ -193,7 +193,15 @@  do_unop (gimple_stmt_iterator *gsi, tree inner_type, tree a,
 	 tree b ATTRIBUTE_UNUSED, tree bitpos, tree bitsize,
 	 enum tree_code code, tree type ATTRIBUTE_UNUSED)
 {
-  a = tree_vec_extract (gsi, inner_type, a, bitsize, bitpos);
+  tree rhs_type = inner_type;
+
+  /* For ABSU_EXPR, use the signed type for the rhs if the rhs was signed. */
+  if (code == ABSU_EXPR
+      && ANY_INTEGRAL_TYPE_P (TREE_TYPE (a))
+      && !TYPE_UNSIGNED (TREE_TYPE (a)))
+    rhs_type = signed_type_for (rhs_type);
+
+  a = tree_vec_extract (gsi, rhs_type, a, bitsize, bitpos);
   return gimplify_build1 (gsi, code, inner_type, a);
 }