re PR tree-optimization/81203 (tail recursion: internal compiler error: verify_ssa failed)

2017-06-26  Richard Biener  <rguenther@suse.de>

	PR tree-optimization/81203
	* tree-tailcall.c (find_tail_calls): Do not move stmts into
	non-dominating BBs.

	* gcc.dg/torture/pr81203.c: New testcase.

From-SVN: r249644

gcc/ChangeLog

+2017-06-26  Richard Biener  <rguenther@suse.de>
+
+	PR tree-optimization/81203
+	* tree-tailcall.c (find_tail_calls): Do not move stmts into
+	non-dominating BBs.
+
 2017-06-26  Marek Polacek  <polacek@redhat.com>
 
 	PR c/80116

gcc/testsuite/ChangeLog

+2017-06-26  Richard Biener  <rguenther@suse.de>
+
+	PR tree-optimization/81203
+	* gcc.dg/torture/pr81203.c: New testcase.
+
 2017-06-26  Marek Polacek  <polacek@redhat.com>
 
 	PR c/80116

gcc/testsuite/gcc.dg/torture/pr81203.c

+/* { dg-do compile } */
+
+int a;
+int b()
+{
+  int c, d;
+  if (a)
+    d = b();
+  return 1 + c + d;
+}

gcc/tree-tailcall.c

@@ -573,6 +573,11 @@ find_tail_calls (basic_block bb, struct tailcall **ret)
 	{
 	  if (! tail_recursion)
 	    return;
+	  /* Do not deal with checking dominance, the real fix is to
+	     do path isolation for the transform phase anyway, removing
+	     the need to compute the accumulators with new stmts.  */
+	  if (abb != bb)
+	    return;
 	  for (unsigned opno = 1; opno < gimple_num_ops (stmt); ++opno)
 	    {
 	      tree op = gimple_op (stmt, opno);