https://gcc.gnu.org/g:bdfb5cc5aa6959a6959fc0cf98da08db89c81032
commit r16-2422-gbdfb5cc5aa6959a6959fc0cf98da08db89c81032
Author: Richard Biener <rguent...@suse.de>
Date: Tue Jul 22 13:02:03 2025 +0200
tree-optimization/121202 - fix vector stmt placement
When we have a vector shift with a scalar the shift operand can be
external - in that case we should not use the shift operand def
as hint where to place the vector shift instruction. The ICE
in the PR is because stmt dominance queries only work inside of
the vector region. But we should also never place stmts outside
of it.
PR tree-optimization/121202
* tree-vect-slp.cc (vect_schedule_slp_node): Do not take
an out-of-region stmt as "last".
* gcc.dg/pr121202.c: New testcase.
Diff:
---
gcc/testsuite/gcc.dg/pr121202.c | 11 +++++++++++
gcc/tree-vect-slp.cc | 6 +++++-
2 files changed, 16 insertions(+), 1 deletion(-)
diff --git a/gcc/testsuite/gcc.dg/pr121202.c b/gcc/testsuite/gcc.dg/pr121202.c
new file mode 100644
index 000000000000..30ecf4a5e01a
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/pr121202.c
@@ -0,0 +1,11 @@
+/* { dg-do compile } */
+/* { dg-options "-O3 -fno-tree-copy-prop" } */
+
+int a, b, c;
+int e(int f, int g) { return f >> g; }
+int h(int f) { return a > 1 ? 0 : f << a; }
+int main() {
+ while (c--)
+ b = e(h(1), a);
+ return 0;
+}
diff --git a/gcc/tree-vect-slp.cc b/gcc/tree-vect-slp.cc
index 7ad56b9a848a..7776b2f1d8e6 100644
--- a/gcc/tree-vect-slp.cc
+++ b/gcc/tree-vect-slp.cc
@@ -11370,7 +11370,11 @@ vect_schedule_slp_node (vec_info *vinfo,
&& !SSA_NAME_IS_DEFAULT_DEF (def))
{
gimple *stmt = SSA_NAME_DEF_STMT (def);
- if (!last_stmt)
+ if (gimple_uid (stmt) == -1u)
+ /* If the stmt is not inside the region do not
+ use it as possible insertion point. */
+ ;
+ else if (!last_stmt)
last_stmt = stmt;
else if (vect_stmt_dominates_stmt_p (last_stmt, stmt))
last_stmt = stmt;
