[Bug c/46454] New: Pointer to pointer function parameter handled incorrectly

[Bug c/46454] New: Pointer to pointer function parameter handled incorrectly

[taradov at gmail dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=46454

           Summary: Pointer to pointer function parameter handled
                    incorrectly
           Product: gcc
           Version: 4.4.5
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c
        AssignedTo: unassigned@gcc.gnu.org
        ReportedBy: taradov@gmail.com


Exact GCC version: gcc version 4.4.5 (Ubuntu/Linaro 4.4.4-14ubuntu5)

Program below when compiled with -O2 or higher produces output like:
------- 0x08724018 0x00000000 0x08724008

With -O1 it produces expected output:
------- 0x09917018 0x09917008 0x09917008

------------------------------------------------
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>

typedef struct List_t
{
  struct List_t *next;
} List_t;

typedef struct Symbol_t
{
  struct Symbol_t *next;
} Symbol_t;

typedef struct First_t
{
  Symbol_t       *set;
} First_t;

static void list_add(void **list, void *element)
{
  ((List_t *)element)->next = NULL;

  if (*list)
  {
    List_t *last = *list;
    while (last->next)
      last = last->next;
    last->next = element;
  }
  else
    *list = element;
}

int main(void)
{
  First_t *item;
  Symbol_t *res;

  res = malloc(sizeof(Symbol_t));
  res->next = NULL;

  item = malloc(sizeof(struct First_t));
  item->set = NULL;
  list_add((void *)&item->set, res);

  printf("------- 0x%08lx 0x%08lx 0x%08x\n", item, item->set, res);
  return 0;
}
--------------------------------------

Bug seems to be fixed in 4.6.x branch, but present in 4.4.x and 4.5.x.

[Bug middle-end/46454] Pointer to pointer function parameter handled incorrectly

[pinskia at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=46454

Andrew Pinski <pinskia at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
          Component|c                           |middle-end

--- Comment #1 from Andrew Pinski <pinskia at gcc dot gnu.org> 2010-11-12 19:14:39 UTC ---
I think this has aliasing violations in it.

[Bug c/46454] Pointer to pointer function parameter handled incorrectly

[taradov at gmail dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=46454

Alexander Taradov <taradov at gmail dot com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
          Component|middle-end                  |c

--- Comment #2 from Alexander Taradov <taradov at gmail dot com> 2010-11-12 19:50:40 UTC ---
(In reply to comment #1)
> I think this has aliasing violations in it.

Yes, my bad.

[Bug middle-end/46454] Pointer to pointer function parameter handled incorrectly

[rguenth at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=46454

Richard Guenther <rguenth at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |RESOLVED
         Resolution|                            |INVALID

--- Comment #3 from Richard Guenther <rguenth at gcc dot gnu.org> 2010-11-12 23:28:54 UTC ---
see comment #2