[PATCH] Fix PR71462

[Richard Biener <rguenther@suse.de>]

I am testing the following patch to robustify into-loop-closed-SSA
rewrite against removed blocks in the changed_bbs bitmap.

Bootstrap and regtest running on x86_64-unknown-linux-gnu.

Richard.

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.

Index: gcc/tree-ssa-loop-manip.c
===================================================================
*** gcc/tree-ssa-loop-manip.c	(revision 237248)
--- gcc/tree-ssa-loop-manip.c	(working copy)
*************** find_uses_to_rename (bitmap changed_bbs,
*** 472,479 ****
  
    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);
    else
      FOR_EACH_BB_FN (bb, cfun)
        find_uses_to_rename_bb (bb, use_blocks, need_phis, use_flags);
--- 472,482 ----
  
    if (changed_bbs)
      EXECUTE_IF_SET_IN_BITMAP (changed_bbs, 0, index, bi)
!       {
! 	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);
Index: gcc/testsuite/gcc.dg/torture/pr71462.c
===================================================================
*** gcc/testsuite/gcc.dg/torture/pr71462.c	(revision 0)
--- gcc/testsuite/gcc.dg/torture/pr71462.c	(working copy)
***************
*** 0 ****
--- 1,28 ----
+ /* { 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;
+ }