From: Richard Guenther <rguenther@suse.de>
Date: Mon, 10 Sep 2012 14:10:09 +0000 (+0000)
Subject: re PR middle-end/54520 (ice in merge_latch_edges with -O3)
X-Git-Tag: misc/gupc_5_2_0_release~290^2
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=1779dc343a559d1d822e8cbcb998bcde049c5123;p=thirdparty%2Fgcc.git

re PR middle-end/54520 (ice in merge_latch_edges with -O3)

2012-09-10  Richard Guenther  <rguenther@suse.de>

	PR tree-optimization/54520
	* tree-ssa-threadupdate.c (def_split_header_continue_p):
	Properly consider sub-loops.

	* gcc.dg/torture/pr54520.c: New testcase.

From-SVN: r191141
---

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 6e7175afd3fd..0e0bc2bdcec5 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,9 @@
+2012-09-10  Richard Guenther  <rguenther@suse.de>
+
+	PR tree-optimization/54520
+	* tree-ssa-threadupdate.c (def_split_header_continue_p):
+	Properly consider sub-loops.
+
 2012-09-10  Richard Henderson  <rth@redhat.com>
 
 	* config/alpha/predicates.md (small_symbolic_operand): Disallow
diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index 65e31bd88048..bd4b362c188a 100644
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,3 +1,8 @@
+2012-09-10  Richard Guenther  <rguenther@suse.de>
+
+	PR tree-optimization/54520
+	* gcc.dg/torture/pr54520.c: New testcase.
+
 2012-09-10  Jason Merrill  <jason@redhat.com>
 
 	PR c++/54506
diff --git a/gcc/testsuite/gcc.dg/torture/pr54520.c b/gcc/testsuite/gcc.dg/torture/pr54520.c
new file mode 100644
index 000000000000..5884b2f353a1
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/torture/pr54520.c
@@ -0,0 +1,15 @@
+/* { dg-do compile } */
+
+char *a;
+void
+fn1 ()
+{
+  char *p = a;
+  while (p && *p != '\0')
+    {
+      while (*p == '\t')
+	*p++ = '\0';
+      if (*p != '\0')
+	p = 0;
+    }
+}
diff --git a/gcc/tree-ssa-threadupdate.c b/gcc/tree-ssa-threadupdate.c
index 30336a18e81f..ba6d69af9428 100644
--- a/gcc/tree-ssa-threadupdate.c
+++ b/gcc/tree-ssa-threadupdate.c
@@ -846,8 +846,9 @@ static bool
 def_split_header_continue_p (const_basic_block bb, const void *data)
 {
   const_basic_block new_header = (const_basic_block) data;
-  return (bb->loop_father == new_header->loop_father
-	  && bb != new_header);
+  return (bb != new_header
+	  && (loop_depth (bb->loop_father)
+	      >= loop_depth (new_header->loop_father)));
 }
 
 /* Thread jumps through the header of LOOP.  Returns true if cfg changes.
@@ -1031,10 +1032,11 @@ thread_through_loop_header (struct loop *loop, bool may_peel_loop_headers)
       nblocks = dfs_enumerate_from (header, 0, def_split_header_continue_p,
 				    bblocks, loop->num_nodes, tgt_bb);
       for (i = 0; i < nblocks; i++)
-	{
-	  remove_bb_from_loops (bblocks[i]);
-	  add_bb_to_loop (bblocks[i], loop_outer (loop));
-	}
+	if (bblocks[i]->loop_father == loop)
+	  {
+	    remove_bb_from_loops (bblocks[i]);
+	    add_bb_to_loop (bblocks[i], loop_outer (loop));
+	  }
       free (bblocks);
 
       /* If the new header has multiple latches mark it so.  */