[Bug middle-end/48016] Inconsistency in non-local goto save area

["hjl.tools at gmail dot com" <gcc-bugzilla at gcc dot gnu dot org>]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=48016

--- Comment #2 from H.J. Lu <hjl.tools at gmail dot com> 2011-03-07 14:40:35 UTC ---
(In reply to comment #1)
> The gimple middle-end only knows one pointer type mode, ptr_type_mode.  If
> we want to save Pmode then we need to use an appropriate integer type
> and a proper alias set.
> 
> I guess this code should be simply replaced to emit RTL directly instead
> of going through expansion of an ARRAY_REF.

For x32 target, we expand function h in:

extern void foo (void) __attribute__((noreturn));
int n;

void
g (void)
{
  __label__ lab;
  void h (void) { if (n == 2) goto lab; }
  void (*f1) (void) = foo;
  void (*f2) (void) = h;

  f2 ();
  if (n)
    f1 ();
  n = 1;
 lab:
  n++;
}

to

h ()
{
  int n.3;
  long long unsigned int[3] * D.2708;

  # BLOCK 2
  # PRED: ENTRY (fallthru)
  n.3_1 = n;
  if (n.3_1 == 2)
    goto <bb 3>;
  else
    goto <bb 4>;
  # SUCC: 3 (true) 4 (false)

  # BLOCK 3
  # PRED: 2 (true)
  D.2708_3 = &CHAIN.5_2(D)->__nl_goto_buf;
  __builtin_nonlocal_goto (&<L2>, D.2708_3);
  # SUCC:

  # BLOCK 4
  # PRED: 2 (false)
  return;
  # SUCC: EXIT

}

I am checking this patch as a workaround on x32 branch.

diff --git a/gcc/ChangeLog.x32 b/gcc/ChangeLog.x32
index f39563b..3f1f953 100644
--- a/gcc/ChangeLog.x32
+++ b/gcc/ChangeLog.x32
@@ -1,3 +1,8 @@
+2011-03-07  H.J. Lu  <hongjiu.lu@intel.com>
+
+    PR middle-end/48016
+    * explow.c (emit_stack_save): Adjust mode of stack save area.
+
 2011-03-06  H.J. Lu  <hongjiu.lu@intel.com>

     * config/i386/predicates.md (aligned_operand): Check SUBREG_REG
diff --git a/gcc/explow.c b/gcc/explow.c
index 3401e49..460af1f 100644
--- a/gcc/explow.c
+++ b/gcc/explow.c
@@ -1008,6 +1008,14 @@ emit_stack_save (enum save_level save_level, rtx *psave)
   do_pending_stack_adjust ();
   if (sa != 0)
     sa = validize_mem (sa);
+  /* FIXME: update_nonlocal_goto_save_area may pass SA in the wrong mode.  */
+  if (GET_MODE (sa) != mode)
+    {
+      gcc_assert (ptr_mode != Pmode
+          && GET_MODE (sa) == ptr_mode
+          && mode == Pmode);
+      sa = adjust_address (sa, mode, 0); 
+    }
   emit_insn (fcn (sa, stack_pointer_rtx));
 }