From: Richard Biener <rguenther@suse.de>
Date: Tue, 2 Sep 2025 07:50:14 +0000 (+0200)
Subject: tree-optimization/121754 - ICE with vect_reduc_type and nested cycle
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=861b7c054e5f356722e6e1a1b043de5d7a412499;p=thirdparty%2Fgcc.git

tree-optimization/121754 - ICE with vect_reduc_type and nested cycle

The reduction guard isn't correct, STMT_VINFO_REDUC_DEF also exists
for nested cycles not part of reductions but there's no reduction
info for them.

	PR tree-optimization/121754
	* tree-vectorizer.h (vect_reduc_type): Simplify to not ICE
	on nested cycles.

	* gcc.dg/vect/pr121754.c: New testcase.
	* gcc.target/aarch64/vect-pr121754.c: Likewise.
---

diff --git a/gcc/testsuite/gcc.dg/vect/pr121754.c b/gcc/testsuite/gcc.dg/vect/pr121754.c
new file mode 100644
index 00000000000..775abda76c5
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/vect/pr121754.c
@@ -0,0 +1,13 @@
+/* { dg-do compile } */
+
+float a;
+void
+fn1 (int b)
+{
+  for (; b < 10; b++)
+    {
+      a = 01.;
+      for (int c = 0; c < 2000; c++)
+        a *= 0.99;
+    }
+}
diff --git a/gcc/testsuite/gcc.target/aarch64/vect-pr121754.c b/gcc/testsuite/gcc.target/aarch64/vect-pr121754.c
new file mode 100644
index 00000000000..8b6a757780d
--- /dev/null
+++ b/gcc/testsuite/gcc.target/aarch64/vect-pr121754.c
@@ -0,0 +1,14 @@
+/* { dg-do compile } */
+/* { dg-options "-O2 -ftree-vectorize -mcpu=neoverse-v2" } */
+
+float a;
+void
+fn1 (int b)
+{
+  for (; b < 10; b++)
+    {
+      a = 01.;
+      for (int c = 0; c < 2000; c++)
+        a *= 0.99;
+    }
+}
diff --git a/gcc/tree-vectorizer.h b/gcc/tree-vectorizer.h
index 87ffe497008..df805c6ade9 100644
--- a/gcc/tree-vectorizer.h
+++ b/gcc/tree-vectorizer.h
@@ -2923,13 +2923,9 @@ vect_reduc_type (vec_info *vinfo, slp_tree node)
 {
   if (loop_vec_info loop_vinfo = dyn_cast<loop_vec_info> (vinfo))
     {
-      stmt_vec_info stmt_info = SLP_TREE_REPRESENTATIVE (node);
-      if (STMT_VINFO_REDUC_DEF (stmt_info))
-	{
-	  vect_reduc_info reduc_info
-	    = info_for_reduction (loop_vinfo, node);
-	  return int (VECT_REDUC_INFO_TYPE (reduc_info));
-	}
+      vect_reduc_info reduc_info = info_for_reduction (loop_vinfo, node);
+      if (reduc_info)
+	return int (VECT_REDUC_INFO_TYPE (reduc_info));
     }
   return -1;
 }