re PR tree-optimization/71462 (gcc ICE at -O3 on valid code on x86_64-linux-gnu with “seg fault”)

2016-06-09  Richard Biener  <rguenther@suse.de>

	PR tree-optimization/71462
	* tree-ssa-loop-manip.c (find_uses_to_rename): Guard against
	removed blocks.

	* gcc.dg/torture/pr71462.c: New testcase.

From-SVN: r237254

gcc/ChangeLog

+2016-06-09  Richard Biener  <rguenther@suse.de>
+
+	PR tree-optimization/71462
+	* tree-ssa-loop-manip.c (find_uses_to_rename): Guard against
+	removed blocks.
+
 2016-06-09  Martin Liska  <mliska@suse.cz>
 
 	* predict.c (filter_predictions): New function.

gcc/testsuite/ChangeLog

+2016-06-09  Richard Biener  <rguenther@suse.de>
+
+	PR tree-optimization/71462
+	* gcc.dg/torture/pr71462.c: New testcase.
+
 2016-06-09  Marek Polacek  <polacek@redhat.com>
 
 	PR c/65471

gcc/testsuite/gcc.dg/torture/pr71462.c

+/* { dg-do compile } */
+
+short a;
+long b;
+void fn1()
+{
+  int c = a = 1;
+  for (; a; a++)
+    {
+      for (; 9 <= 8;)
+	for (;;) {
+	    a = 20;
+	    for (; a <= 35; a++)
+	      ;
+line:;
+	}
+      if ((c += 264487869) == 9)
+	{
+	  unsigned *d = 0;
+	  for (; b;)
+	    d = (unsigned *)&c;
+	  if (d)
+	    for (;;)
+	      ;
+	}
+    }
+  goto line;
+}

gcc/tree-ssa-loop-manip.c

@@ -472,8 +472,11 @@ find_uses_to_rename (bitmap changed_bbs, bitmap *use_blocks, bitmap need_phis,
 
   if (changed_bbs)
     EXECUTE_IF_SET_IN_BITMAP (changed_bbs, 0, index, bi)
-      find_uses_to_rename_bb (BASIC_BLOCK_FOR_FN (cfun, index), use_blocks,
-			      need_phis, use_flags);
+      {
+	bb = BASIC_BLOCK_FOR_FN (cfun, index);
+	if (bb)
+	  find_uses_to_rename_bb (bb, use_blocks, need_phis, use_flags);
+      }
   else
     FOR_EACH_BB_FN (bb, cfun)
       find_uses_to_rename_bb (bb, use_blocks, need_phis, use_flags);