re PR tree-optimization/89509 (restrict doesnt work with subfield accesses)

2019-05-02  Richard Biener  <rguenther@suse.de>

	PR tree-optimization/89509
	* tree-ssa-structalias.c (compute_dependence_clique): Look
	at the first subvar when determining whether it is restrict.

	* gcc.dg/torture/restrict-8.c: New testcase.

From-SVN: r270799

gcc/ChangeLog

 2019-05-02  Richard Biener  <rguenther@suse.de>
 
+	PR tree-optimization/89509
+	* tree-ssa-structalias.c (compute_dependence_clique): Look
+	at the first subvar when determining whether it is restrict.
+
+2019-05-02  Richard Biener  <rguenther@suse.de>
+
 	PR tree-optimization/90273
 	* tree-ssa-dce.c (eliminate_unnecessary_stmts): Eliminate
 	useless debug stmts.

gcc/testsuite/ChangeLog

+2019-05-02  Richard Biener  <rguenther@suse.de>
+
+	PR tree-optimization/89509
+	* gcc.dg/torture/restrict-8.c: New testcase.
+
 2019-05-02  Iain Sandoe  <iain@sandoe.co.uk>
 
 	* gcc.dg/tree-prof/section-attr-1.c: Update scan-asm regex

gcc/testsuite/gcc.dg/torture/restrict-8.c

+/* { dg-do compile } */
+/* { dg-skip-if "" { *-*-* } { "-O0" } { "" } } */
+/* { dg-options "-fdump-tree-fre1" } */
+
+struct S { int i; void *p; int j; };
+int
+foo (struct S * __restrict p, int *q, int flag)
+{
+  int *x = &p->j;
+  if (flag)
+    x = &p->i;
+  *q = 1;
+  *x = 2;
+  return *q;
+}
+
+/* { dg-final { scan-tree-dump "return 1;" "fre1" } } */

gcc/tree-ssa-structalias.c

@@ -7588,9 +7588,12 @@ compute_dependence_clique (void)
       EXECUTE_IF_SET_IN_BITMAP (vi->solution, 0, j, bi)
 	{
 	  varinfo_t oi = get_varinfo (j);
+	  if (oi->head != j)
+	    oi = get_varinfo (oi->head);
 	  if (oi->is_restrict_var)
 	    {
-	      if (restrict_var)
+	      if (restrict_var
+		  && restrict_var != oi)
 		{
 		  if (dump_file && (dump_flags & TDF_DETAILS))
 		    {