re PR tree-optimization/64357 (ICE at -Os on x86_64-linux-gnu in…

re PR tree-optimization/64357 (ICE at -Os on x86_64-linux-gnu in check_loop_closed_ssa_use, at tree-ssa-loop-manip.c:579)

2015-01-12  Richard Biener  <rguenther@suse.de>

	PR middle-end/64357
	* tree-cfg.c (gimple_can_merge_blocks_p): Protect simple
	latches properly.

	* gcc.dg/torture/pr64357.c: New testcase.

From-SVN: r219473

gcc/ChangeLog

+2015-01-12  Richard Biener  <rguenther@suse.de>
+
+	PR middle-end/64357
+	* tree-cfg.c (gimple_can_merge_blocks_p): Protect simple
+	latches properly.
+
 2015-01-12  Kyrylo Tkachov  <kyrylo.tkachov@arm.com>
 
 	* config/arm/arm.c (arm_cortex_a12_tune): Update entries to match

gcc/testsuite/ChangeLog

+2015-01-12  Richard Biener  <rguenther@suse.de>
+
+	PR middle-end/64357
+	* gcc.dg/torture/pr64357.c: New testcase.
+
 2015-01-12  H.J. Lu  <hongjiu.lu@intel.com>
 
 	* gcc.target/i386/nop-mcount.c: Properly place {} in target

gcc/testsuite/gcc.dg/torture/pr64357.c

+/* { dg-do compile } */
+
+int a, b, c, d, e, f;
+
+long long
+fn1 (int p)
+{
+  return p ? p : 1;
+}
+
+static int
+fn2 ()
+{
+lbl:
+  for (; f;)
+    return 0;
+  for (;;)
+    {
+      for (b = 0; b; ++b)
+	if (d)
+	  goto lbl;
+      c = e;
+    }
+}
+
+void
+fn3 ()
+{
+  for (; a; a = fn1 (a))
+    {
+      fn2 ();
+      e = 0;
+    }
+}

gcc/tree-cfg.c

@@ -1723,11 +1723,13 @@ gimple_can_merge_blocks_p (basic_block a, basic_block b)
     }
 
   /* Protect simple loop latches.  We only want to avoid merging
-     the latch with the loop header in this case.  */
+     the latch with the loop header or with a block in another
+     loop in this case.  */
   if (current_loops
       && b->loop_father->latch == b
       && loops_state_satisfies_p (LOOPS_HAVE_SIMPLE_LATCHES)
-      && b->loop_father->header == a)
+      && (b->loop_father->header == a
+	  || b->loop_father != a->loop_father))
     return false;
 
   /* It must be possible to eliminate all phi nodes in B.  If ssa form