[3.5/3.4] Fix bug in tree-inline.c

[Josef Zlomek <zlomj9am at artax dot karlin dot mff dot cuni dot cz>]

Hello,

when compiling attached testcase on x86-64 or powerpc64 with -O3
I get a ICE in verify flow info with error message "Wrong amount of branch edges
after unconditional jump"
because of this insn:

(jump_insn 82 81 83 (set (pc)
        (label_ref 0)) -1 (nil)
	    (nil))

I analyzed how label_ref 0 came there and found the problem.

For some reason, function "b" gets inlined into "a", and then "a" into "b".
In the second inlining, we replace RETURN_STMT with GOTO ret_label
in copy_body_r () as usual.
But when we continue walking through the tree we reach the new
GOTO ret_label and make a copy of the ret_label because
(*lang_hooks.tree_inlining.auto_var_in_fn_p) (*tp, fn) == true
because DECL_CONTEXT (*tp) == fn  (see lhd_tree_inlining_auto_var_in_fn_p).
The copied ret_label is not of course emitted to code because it is not
elsewhere in the tree and gets expanded to that (label_ref 0).
This happens only when inlining a function into itself via transitivity.

The ret_label should not be copied because we inserted it there
in replacement of RETURN_STMT.
The following patch fixes it.

Bootstrapped/regtested x86-64.
OK for mainline and 3.4 branch?

Josef

-----------testcase-------------
typedef struct xdef xdef;
struct xdef
{
  char xtyp;
  xdef *next;
  int y;
};

extern void b ();
extern void *foo (void *bar);
extern void *foo2 (void *bar1, void *bar2);
extern void *qwe;

static void
c (xdef * xp)
{
  b (xp);
}
static void
a (xdef ** xpp)
{
  xdef *xp;
  xp = *xpp;

  foo (xp);
  xp = foo2 (xp, qwe);
  b (xp->next);
  foo (xp);
  if (xp->y)
  {
    foo (xp);
    if (xp)
    {
      xdef *p = foo2 (xp, qwe);
      foo2 (xp, p);
      xp = foo (p);
    }
    else
    {
      foo2 (foo(*xpp), *xpp);
    }
  }
  *xpp = foo2 (xpp, qwe);
}

void
b (xdef ** xpp)
{
  xdef *xp = *xpp;
  if (!xp)
    return;
  if (xp->xtyp == 0)
    a (xpp);
  c (xp);
}
---------------------------------

2004-02-14  Josef Zlomek  <zlomekj@suse.cz>

	* tree-inline.c (copy_body_r): Do not replace ret_label.

Index: tree-inline.c
===================================================================
RCS file: /cvs/gcc-cvs/gcc/gcc/tree-inline.c,v
retrieving revision 1.34.2.17
diff -c -p -c -3 -p -r1.34.2.17 tree-inline.c
*** tree-inline.c	3 Jan 2004 18:13:44 -0000	1.34.2.17
--- tree-inline.c	26 Jan 2004 20:09:30 -0000
*************** copy_body_r (tp, walk_subtrees, data)
*** 490,497 ****
    /* Local variables and labels need to be replaced by equivalent
       variables.  We don't want to copy static variables; there's only
       one of those, no matter how many times we inline the containing
!      function.  */
!   else if ((*lang_hooks.tree_inlining.auto_var_in_fn_p) (*tp, fn))
      {
        tree new_decl;
  
--- 490,500 ----
    /* Local variables and labels need to be replaced by equivalent
       variables.  We don't want to copy static variables; there's only
       one of those, no matter how many times we inline the containing
!      function.
!      We do not also want to copy the label which we put into
!      GOTO_STMT which replaced RETURN_STMT.  */
!   else if (*tp != id->ret_label
! 	   && (*lang_hooks.tree_inlining.auto_var_in_fn_p) (*tp, fn))
      {
        tree new_decl;