[PATCH] Fix PR51071

[Richard Guenther <rguenther at suse dot de>]

When using gimple_has_side_effects on a GIMPLE_LABEL with a
LABEL_DECL with DECL_FORCED_LABEL set we ICE.  That is because
gimple_has_side_effects uses TREE_SIDE_EFFECTS on the LABEL_DECL
which isn't valid.  Fixed by (finally) cleaning up this
predicate, removing all code that can only be executed if we
eventually ICE and has no other side-effects.

Bootstrapped on x86_64-unknown-linux-gnu, testing in progress.

Richard.

2011-11-10  Richard Guenther  <rguenther@suse.de>

	PR middle-end/51071
	* gimple.c (gimple_has_side_effects): Remove checking code
	that doesn't belong here.

	* gcc.dg/torture/pr51071.c: New testcase.

Index: gcc/gimple.c
===================================================================
*** gcc/gimple.c	(revision 181206)
--- gcc/gimple.c	(working copy)
*************** gimple_set_modified (gimple s, bool modi
*** 2457,2464 ****
  bool
  gimple_has_side_effects (const_gimple s)
  {
-   unsigned i;
- 
    if (is_gimple_debug (s))
      return false;
  
--- 2457,2462 ----
*************** gimple_has_side_effects (const_gimple s)
*** 2474,2520 ****
  
    if (is_gimple_call (s))
      {
!       unsigned nargs = gimple_call_num_args (s);
!       tree fn;
  
!       if (!(gimple_call_flags (s) & (ECF_CONST | ECF_PURE)))
!         return true;
!       else if (gimple_call_flags (s) & ECF_LOOPING_CONST_OR_PURE)
! 	/* An infinite loop is considered a side effect.  */
  	return true;
  
-       if (gimple_call_lhs (s)
-           && TREE_SIDE_EFFECTS (gimple_call_lhs (s)))
- 	{
- 	  gcc_checking_assert (gimple_has_volatile_ops (s));
- 	  return true;
- 	}
- 
-       fn = gimple_call_fn (s);
-       if (fn && TREE_SIDE_EFFECTS (fn))
-         return true;
- 
-       for (i = 0; i < nargs; i++)
-         if (TREE_SIDE_EFFECTS (gimple_call_arg (s, i)))
- 	  {
- 	    gcc_checking_assert (gimple_has_volatile_ops (s));
- 	    return true;
- 	  }
- 
        return false;
      }
-   else
-     {
-       for (i = 0; i < gimple_num_ops (s); i++)
- 	{
- 	  tree op = gimple_op (s, i);
- 	  if (op && TREE_SIDE_EFFECTS (op))
- 	    {
- 	      gcc_checking_assert (gimple_has_volatile_ops (s));
- 	      return true;
- 	    }
- 	}
-     }
  
    return false;
  }
--- 2472,2486 ----
  
    if (is_gimple_call (s))
      {
!       int flags = gimple_call_flags (s);
  
!       /* An infinite loop is considered a side effect.  */
!       if (!(flags & (ECF_CONST | ECF_PURE))
! 	  || (flags & ECF_LOOPING_CONST_OR_PURE))
  	return true;
  
        return false;
      }
  
    return false;
  }
Index: gcc/testsuite/gcc.dg/torture/pr51071.c
===================================================================
*** gcc/testsuite/gcc.dg/torture/pr51071.c	(revision 0)
--- gcc/testsuite/gcc.dg/torture/pr51071.c	(revision 0)
***************
*** 0 ****
--- 1,33 ----
+ /* { dg-do compile } */
+ 
+ void foo (void);
+ void bar (void *);
+ extern int t;
+ 
+ static void kmalloc_large (int size, int flags)
+ {
+   (void) size;
+   (void) flags;
+   foo ();
+   bar (({__here:&&__here;}));
+ }
+ 
+ static void kmalloc (int size, int flags)
+ {
+   if (size)
+     {
+       if ((unsigned long) size > 0x1000)
+ 	kmalloc_large (size, flags);
+ 
+       if (flags)
+ 	bar (({__here:&&__here;}));
+     }
+ }
+ 
+ void compress_file_range (int i, int j, int k)
+ {
+   int nr_pages = ({j < k;});
+ 
+   if (i || t)
+     kmalloc (0x1000UL * nr_pages, 0x40UL);
+ }