[PATCH] Fix PR81203

[Richard Biener <rguenther@suse.de>]

Bootstrapped and tested on x86_64-unknown-linux-gnu, applied.

Richard.

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.

Index: gcc/tree-tailcall.c
===================================================================
--- gcc/tree-tailcall.c	(revision 249638)
+++ gcc/tree-tailcall.c	(working copy)
@@ -573,6 +573,11 @@ find_tail_calls (basic_block bb, struct
 	{
 	  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);
Index: gcc/testsuite/gcc.dg/torture/pr81203.c
===================================================================
--- gcc/testsuite/gcc.dg/torture/pr81203.c	(nonexistent)
+++ gcc/testsuite/gcc.dg/torture/pr81203.c	(working copy)
@@ -0,0 +1,10 @@
+/* { dg-do compile } */
+
+int a;
+int b()
+{
+  int c, d;
+  if (a)
+    d = b();
+  return 1 + c + d;
+}