re PR tree-optimization/71261 (Trunk GCC hangs on knl and broadwell targets)

2016-05-25  Richard Biener  <rguenther@suse.de>

	PR tree-optimization/71261
	* tree-if-conv.c (ifcvt_split_def_stmt): Walk uses on the
	interesting stmt instead of immediate uses when looking
	for the use operand to replace.

	* c-c++-common/torture/pr71261.c: New testcase.

From-SVN: r236701

gcc/ChangeLog

+2016-05-25  Richard Biener  <rguenther@suse.de>
+
+	PR tree-optimization/71261
+	* tree-if-conv.c (ifcvt_split_def_stmt): Walk uses on the
+	interesting stmt instead of immediate uses when looking
+	for the use operand to replace.
+
 2016-05-25  Martin Liska  <mliska@suse.cz>
 
 	* ipa-inline.c (edge_badness): Use 'w/' instead of 'w'.

gcc/testsuite/ChangeLog

 2016-05-25  Richard Biener  <rguenther@suse.de>
 
+	PR tree-optimization/71261
+	* c-c++-common/torture/pr71261.c: New testcase.
+
+2016-05-25  Richard Biener  <rguenther@suse.de>
+
 	PR tree-optimization/71264
 	* gcc.dg/vect/pr71264.c: New testcase.
 

gcc/testsuite/c-c++-common/torture/pr71261.c

+/* { dg-do compile } */
+/* { dg-additional-options "-mavx2" { target x86_64-*-* i?86-*-* } } */
+
+extern int a, b, c, d, e, f;
+void fn1()
+{
+  for (int g = 0; g < d; g = 1)
+    for (int h = 0; h < 8; h = h + 2)
+      for (int i = h; i < h + 2; i = i + 1)
+	f = a && e || c && b;
+}

gcc/tree-if-conv.c

@@ -2529,7 +2529,7 @@ ifcvt_split_def_stmt (gimple *def_stmt, gimple *use_stmt)
   gimple *copy_stmt;
   gimple_stmt_iterator gsi;
   use_operand_p use_p;
-  imm_use_iterator imm_iter;
+  ssa_op_iter iter;
 
   var = gimple_assign_lhs (def_stmt);
   copy_stmt = gimple_copy (def_stmt);
@@ -2548,9 +2548,9 @@ ifcvt_split_def_stmt (gimple *def_stmt, gimple *use_stmt)
       print_generic_expr (dump_file, lhs, TDF_SLIM);
       fprintf (dump_file, "\n");
     }
-  FOR_EACH_IMM_USE_FAST (use_p, imm_iter, var)
+  FOR_EACH_SSA_USE_OPERAND (use_p, use_stmt, iter, SSA_OP_USE)
     {
-      if (USE_STMT (use_p) != use_stmt)
+      if (USE_FROM_PTR (use_p) != var)
 	continue;
       SET_USE (use_p, lhs);
       break;