re PR tree-optimization/63677 (Failure to constant fold with vectorization.)

2014-11-20   Richard Biener  <rguenther@suse.de>

	PR tree-optimization/63677
	* tree-ssa-dom.c: Include gimplify.h for unshare_expr.
	(avail_exprs_stack): Make a vector of pairs.
	(struct hash_expr_elt): Replace stmt member with vop member.
	(expr_elt_hasher::equal): Simplify.
	(initialize_hash_element): Adjust.
	(initialize_hash_element_from_expr): Likewise.
	(dom_opt_dom_walker::thread_across_edge): Likewise.
	(record_cond): Likewise.
	(dom_opt_dom_walker::before_dom_children): Likewise.
	(print_expr_hash_elt): Likewise.
	(remove_local_expressions_from_table): Restore previous state
	if requested.
	(record_equivalences_from_stmt): Record &x + CST as constant
	&MEM[&x, CST] for further propagation.
	(vuse_eq): New function.
	(lookup_avail_expr): For loads use the alias oracle to see
	whether a candidate from the expr hash is usable.
	(avail_expr_hash): Do not hash VUSEs.

	* gcc.dg/tree-ssa/ssa-dom-cse-2.c: New testcase.
	* gcc.dg/tree-ssa/ssa-dom-cse-3.c: Likewise.

From-SVN: r217827

gcc/ChangeLog

+2014-11-20   Richard Biener  <rguenther@suse.de>
+
+	PR tree-optimization/63677
+	* tree-ssa-dom.c: Include gimplify.h for unshare_expr.
+	(avail_exprs_stack): Make a vector of pairs.
+	(struct hash_expr_elt): Replace stmt member with vop member.
+	(expr_elt_hasher::equal): Simplify.
+	(initialize_hash_element): Adjust.
+	(initialize_hash_element_from_expr): Likewise.
+	(dom_opt_dom_walker::thread_across_edge): Likewise.
+	(record_cond): Likewise.
+	(dom_opt_dom_walker::before_dom_children): Likewise.
+	(print_expr_hash_elt): Likewise.
+	(remove_local_expressions_from_table): Restore previous state
+	if requested.
+	(record_equivalences_from_stmt): Record &x + CST as constant
+	&MEM[&x, CST] for further propagation.
+	(vuse_eq): New function.
+	(lookup_avail_expr): For loads use the alias oracle to see
+	whether a candidate from the expr hash is usable.
+	(avail_expr_hash): Do not hash VUSEs.
+
 2014-11-20  Ramana Radhakrishnan  <ramana.radhakrishnan@arm.com>
 
 	PR target/59593

gcc/testsuite/ChangeLog

+2014-11-20   Richard Biener  <rguenther@suse.de>
+
+	PR tree-optimization/63677
+	* gcc.dg/tree-ssa/ssa-dom-cse-2.c: New testcase.
+	* gcc.dg/tree-ssa/ssa-dom-cse-3.c: Likewise.
+
 2014-11-20  Igor Zamyatin  <igor.zamyatin@intel.com>
 
 	PR sanitizer/63845

gcc/testsuite/gcc.dg/tree-ssa/ssa-dom-cse-2.c

+/* { dg-do compile } */
+/* { dg-options "-O3 -fno-tree-fre -fno-tree-pre -fdump-tree-optimized" } */
+
+int
+foo ()
+{
+  const int a[8] = { 0, 1, 2, 3, 4, 5, 6, 7 };
+  int i, sum;
+
+  sum = 0;
+  for (i = 0; i < sizeof (a) / sizeof (*a); i++)
+    sum += a[i];
+
+  return sum;
+}
+
+/* After late unrolling the above loop completely DOM should be
+   able to optimize this to return 28.  */
+
+/* { dg-final { scan-tree-dump "return 28;" "optimized" } } */
+/* { dg-final { cleanup-tree-dump "optimized" } } */

gcc/testsuite/gcc.dg/tree-ssa/ssa-dom-cse-3.c

+/* { dg-do run } */
+/* { dg-options "-O -fno-tree-fre -fdump-tree-dom1" } */
+
+extern void abort (void);
+
+int a;
+int __attribute__((noinline))
+foo (int b)
+{
+  a = 0;
+  if (b)
+    {
+      a = 1;
+      return a;
+    }
+  /* DOM should be able to CSE both loads here, forwarding 0 and 1
+     to the PHI feeding the return.  */
+  return a;
+}
+
+int
+main()
+{
+  if (foo (0) != 0
+      || foo (1) != 1)
+    abort ();
+  return 0;
+}
+
+/* { dg-final { scan-tree-dump "= PHI <\[01\]\\\(.\\\), \[01\]\\\(.\\\)>" "dom1" } } */
+/* { dg-final { cleanup-tree-dump "dom1" } } */