https://gcc.gnu.org/g:39ba01fe70c77e70a00ed65a1e6bac8350479f4d
commit r16-2295-g39ba01fe70c77e70a00ed65a1e6bac8350479f4d
Author: Richard Biener <rguent...@suse.de>
Date: Wed Jul 16 14:07:48 2025 +0200
tree-optimization/121116 - avoid _BitInt for vector element init
When having a _BitInt induction we should make sure to not create
the step vector elements as _BitInts but as vector element typed.
PR tree-optimization/121116
* tree-vect-loop.cc (vectorizable_induction): Use the
step vector element type for further processing.
* gcc.dg/torture/pr121116.c: New testcase.
Diff:
---
gcc/testsuite/gcc.dg/torture/pr121116.c | 21 +++++++++++++++++++++
gcc/tree-vect-loop.cc | 1 +
2 files changed, 22 insertions(+)
diff --git a/gcc/testsuite/gcc.dg/torture/pr121116.c
b/gcc/testsuite/gcc.dg/torture/pr121116.c
new file mode 100644
index 000000000000..637324fb4fde
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/torture/pr121116.c
@@ -0,0 +1,21 @@
+/* { dg-do run { target bitint } } */
+
+#include <stdlib.h>
+#include <stdckdint.h>
+#include <string.h>
+typedef _BitInt(16) bit16;
+[[nodiscard]] static bit16 process_data(bit16 input) {
+ _Static_assert(sizeof(bit16) == 2, "Unexpected size of bit16");
+ return (input << 5) | (input >> 9);
+}
+int main(void) {
+ const bit16 data = 0b101'0101'0000'0000;
+ bit16 result = 0;
+ for (bit16 i = 0; i < 0b1000; ++i) {
+ result ^= process_data(data ^ i);
+ }
+ if (ckd_add(&result, result, 0x1234)) {
+ return EXIT_FAILURE;
+ }
+ return (result & 0xFF00) ? 0 : 1;
+}
diff --git a/gcc/tree-vect-loop.cc b/gcc/tree-vect-loop.cc
index 734b7ef52e7b..edad40cef302 100644
--- a/gcc/tree-vect-loop.cc
+++ b/gcc/tree-vect-loop.cc
@@ -9831,6 +9831,7 @@ vectorizable_induction (loop_vec_info loop_vinfo,
}
tree stept = TREE_TYPE (step_expr);
tree step_vectype = get_same_sized_vectype (stept, vectype);
+ stept = TREE_TYPE (step_vectype);
/* Check for target support of the vectorized arithmetic used here. */
if (!target_supports_op_p (step_vectype, PLUS_EXPR, optab_default)
