https://gcc.gnu.org/g:b3f9f10e03c570074a517dcfe9df8d3eeddd6aca
commit r13-8680-gb3f9f10e03c570074a517dcfe9df8d3eeddd6aca
Author: Richard Biener <rguent...@suse.de>
Date: Tue Apr 16 10:46:03 2024 +0200
tree-optimization/114733 - neg induction fails for 1 element vectors
The neg induction vectorization code isn't prepared to deal with
single element vectors.
PR tree-optimization/114733
* tree-vect-loop.cc (vectorizable_nonlinear_induction): Reject
neg induction vectorization of single element vectors.
* gcc.dg/vect/pr114733.c: New testcase.
(cherry picked from commit 45a41ace55d0ffb1097e374868242329788ec82a)
Diff:
---
gcc/testsuite/gcc.dg/vect/pr114733.c | 20 ++++++++++++++++++++
gcc/tree-vect-loop.cc | 2 ++
2 files changed, 22 insertions(+)
diff --git a/gcc/testsuite/gcc.dg/vect/pr114733.c
b/gcc/testsuite/gcc.dg/vect/pr114733.c
new file mode 100644
index 00000000000..219cbf20469
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/vect/pr114733.c
@@ -0,0 +1,20 @@
+/* { dg-additional-options "-O3" } */
+
+#include "tree-vect.h"
+
+long b = 1;
+signed char c;
+int d[25];
+
+int main()
+{
+ check_vect ();
+ for (signed char g = 0; g < 8; g += 1)
+ for (short h = 0; h < 25; h += 2) {
+ b *= -1;
+ c ^= d[h];
+ }
+ if (b != 1)
+ abort ();
+ return 0;
+}
diff --git a/gcc/tree-vect-loop.cc b/gcc/tree-vect-loop.cc
index 31ced32126e..73caeb283e3 100644
--- a/gcc/tree-vect-loop.cc
+++ b/gcc/tree-vect-loop.cc
@@ -8944,6 +8944,8 @@ vectorizable_nonlinear_induction (loop_vec_info
loop_vinfo,
switch (induction_type)
{
case vect_step_op_neg:
+ if (maybe_eq (TYPE_VECTOR_SUBPARTS (vectype), 1u))
+ return false;
if (TREE_CODE (init_expr) != INTEGER_CST
&& TREE_CODE (init_expr) != REAL_CST)
{
