From: Richard Biener <rguenther@suse.de>
Date: Tue, 23 Apr 2024 06:39:03 +0000 (+0200)
Subject: tree-optimization/114799 - SLP and patterns
X-Git-Tag: basepoints/gcc-15~51
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=18e8e55487238237f37f621668fdee316624981a;p=thirdparty%2Fgcc.git

tree-optimization/114799 - SLP and patterns

The following plugs a hole with computing whether a SLP node has any
pattern stmts which is important to know when we want to replace it
by a CTOR from external defs.

	PR tree-optimization/114799
	* tree-vect-slp.cc (vect_get_and_check_slp_defs): Properly
	update ->any_pattern when swapping operands.

	* gcc.dg/vect/bb-slp-pr114799.c: New testcase.
---

diff --git a/gcc/testsuite/gcc.dg/vect/bb-slp-pr114799.c b/gcc/testsuite/gcc.dg/vect/bb-slp-pr114799.c
new file mode 100644
index 000000000000..70572fe703ba
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/vect/bb-slp-pr114799.c
@@ -0,0 +1,16 @@
+/* { dg-do compile } */
+/* { dg-additional-options "-fno-tree-forwprop" } */
+
+unsigned long x;
+unsigned char y;
+
+void
+foo (void)
+{
+  unsigned long tt = y;
+  tt+=255;
+  unsigned short t1 = tt;
+  t1 = 254 - t1;
+  tt += ((unsigned long)t1);
+  x = tt;
+}
diff --git a/gcc/tree-vect-slp.cc b/gcc/tree-vect-slp.cc
index 30589e19a175..133606fa6f3c 100644
--- a/gcc/tree-vect-slp.cc
+++ b/gcc/tree-vect-slp.cc
@@ -888,6 +888,12 @@ vect_get_and_check_slp_defs (vec_info *vinfo, unsigned char swap,
 			 (*oprnds_info)[i+1]->def_stmts[stmt_num]);
 	      std::swap ((*oprnds_info)[i]->ops[stmt_num],
 			 (*oprnds_info)[i+1]->ops[stmt_num]);
+	      /* After swapping some operands we lost track whether an
+		 operand has any pattern defs so be conservative here.  */
+	      if ((*oprnds_info)[i]->any_pattern
+		  || (*oprnds_info)[i+1]->any_pattern)
+		(*oprnds_info)[i]->any_pattern
+		  = (*oprnds_info)[i+1]->any_pattern = true;
 	      swapped = true;
 	      continue;
 	    }