[PATCH] Fix PR81203

[Richard Biener]

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

Richard.

2017-06-26  Richard Biener  <rguent...@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;
+}