From: Richard Biener <rguenther@suse.de>
Date: Fri, 30 Aug 2024 09:39:53 +0000 (+0200)
Subject: Do not bother with reassociation in SLP discovery for single-lane
X-Git-Tag: basepoints/gcc-16~6237
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=e7c7397236544f0e7dbb1ffa635b58126157dc86;p=thirdparty%2Fgcc.git

Do not bother with reassociation in SLP discovery for single-lane

It just clutters the dump files and takes up compile-time.

	* tree-vect-slp.cc (vect_build_slp_tree_2): Disable SLP
	reassociation for single-lane.
---

diff --git a/gcc/tree-vect-slp.cc b/gcc/tree-vect-slp.cc
index cfdf59ad386..621ebf670c7 100644
--- a/gcc/tree-vect-slp.cc
+++ b/gcc/tree-vect-slp.cc
@@ -2082,6 +2082,8 @@ vect_build_slp_tree_2 (vec_info *vinfo, slp_tree node,
      for matching as we can succeed by means of builds from scalars
      and have no good way to "cost" one build against another.  */
   else if (is_a <loop_vec_info> (vinfo)
+	   /* Do not bother for single-lane SLP.  */
+	   && group_size > 1
 	   /* ???  We don't handle !vect_internal_def defs below.  */
 	   && STMT_VINFO_DEF_TYPE (stmt_info) == vect_internal_def
 	   /* ???  Do not associate a reduction, this will wreck REDUC_IDX