From: Richard Biener <rguenther@suse.de>
Date: Fri, 30 May 2025 12:11:47 +0000 (+0200)
Subject: tree-optimization/120357 - ICE with early break vectorization
X-Git-Tag: releases/gcc-15.2.0~414
X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=8cb0127dfd3d01d4549f3139b087d1a5966844ee;p=thirdparty%2Fgcc.git

tree-optimization/120357 - ICE with early break vectorization

When doing early break vectorization of a loop with a conditional
reduction the epilog creation code is confused as to before which exit
to insert the conditional reduction induction IV update.  The
following make sure this is done before the main IV exit.

	PR tree-optimization/120357
	* tree-vect-loop.cc (vect_create_epilog_for_reduction): Create
	the conditional reduction induction IV increment before the
	main IV exit.

	* gcc.dg/vect/vect-early-break_136-pr120357.c: New testcase.

(cherry picked from commit dce4da51ab66c3abb84448326910cd42f6fe2499)
---

diff --git a/gcc/testsuite/gcc.dg/vect/vect-early-break_136-pr120357.c b/gcc/testsuite/gcc.dg/vect/vect-early-break_136-pr120357.c
new file mode 100644
index 00000000000..8a51cfc46a5
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/vect/vect-early-break_136-pr120357.c
@@ -0,0 +1,13 @@
+/* { dg-do compile } */
+/* { dg-add-options vect_early_break } */
+/* { dg-additional-options "-O3" } */
+
+char a;
+unsigned long long t[2][22];
+int u[22];
+void f(void)
+{
+  for (int v = 0; v < 22; v++)
+    for (_Bool w = 0; w < (u[v] < 0) + 1; w = 1)
+      a *= 0 != t[w][v];
+}
diff --git a/gcc/tree-vect-loop.cc b/gcc/tree-vect-loop.cc
index 2d35fa12886..c824b5abaaf 100644
--- a/gcc/tree-vect-loop.cc
+++ b/gcc/tree-vect-loop.cc
@@ -6189,7 +6189,8 @@ vect_create_epilog_for_reduction (loop_vec_info loop_vinfo,
       /* Create an induction variable.  */
       gimple_stmt_iterator incr_gsi;
       bool insert_after;
-      vect_iv_increment_position (loop_exit, &incr_gsi, &insert_after);
+      vect_iv_increment_position (LOOP_VINFO_IV_EXIT (loop_vinfo),
+				  &incr_gsi, &insert_after);
       create_iv (series_vect, PLUS_EXPR, vec_step, NULL_TREE, loop, &incr_gsi,
 		 insert_after, &indx_before_incr, &indx_after_incr);