From: Richard Biener <rguenther@suse.de>
Date: Wed, 26 Jun 2024 17:23:26 +0000 (+0200)
Subject: tree-optimization/115652 - amend last fix
X-Git-Tag: basepoints/gcc-16~7883
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=c7cb0dd94589ab501bca27f93641b4074e5a2e99;p=thirdparty%2Fgcc.git

tree-optimization/115652 - amend last fix

The previous fix breaks in the degenerate case when the discovered
last_stmt is equal to the first stmt in the block since then we
undo a required stmt advancement.

	PR tree-optimization/115652
	* tree-vect-slp.cc (vect_schedule_slp_node): Only insert
	at the start of the block if that strictly dominates
	the discovered dependent stmt.
---

diff --git a/gcc/tree-vect-slp.cc b/gcc/tree-vect-slp.cc
index 1f5b3fccf41..1252b613125 100644
--- a/gcc/tree-vect-slp.cc
+++ b/gcc/tree-vect-slp.cc
@@ -9747,7 +9747,8 @@ vect_schedule_slp_node (vec_info *vinfo,
 	      {
 		gimple_stmt_iterator si2
 		  = gsi_after_labels (LOOP_VINFO_LOOP (loop_vinfo)->header);
-		if (vect_stmt_dominates_stmt_p (last_stmt, *si2))
+		if (last_stmt != *si2
+		    && vect_stmt_dominates_stmt_p (last_stmt, *si2))
 		  si = si2;
 	      }
 	}