Bug#635214: gcc-4.6: [sparc] miscompile PARI/GP 2.5.0 [test-case provided]

[Bill Allombert <ballombe@debian.org>]

Package: gcc-4.6
Version: 4.6.1-4
Severity: normal

Hello Debian GCC Maintainers,

gcc-4.6 miscompiles pari 2.5.0 on sparc, see
See https://buildd.debian.org/status/fetch.php?pkg=pari&arch=sparc&ver=2.5.0-1&stamp=1311418380

Please find a small test-case attached (test.c)

gcc -O2 -g -Wall -fno-strict-aliasing test.c -o test
./test
zsh: segmentation fault  ./test

It does not segfault with -fno-inline and also with -fPIC.

This bug is very similar to 627084 except it only happens on sparc and that the
test-case is simpler.

Cheers,
-- 
Bill. <ballombe@debian.org>

Imagine a large red swirl here. 

#include <stdlib.h>

inline void*
pari_realloc(void *pointer, size_t size)
{
  char *tmp;
  if (!pointer)
    tmp = (char *) malloc(size);
  else
    tmp = (char *) realloc(pointer,size);
  return tmp;
}

typedef struct {
  long offset;
  long n;
  long alloc;
  size_t size;
} pari_stack;

inline void **
stack_base(pari_stack *s) { return (void **) ((char *)s+s->offset); }

inline void
stack_init(pari_stack *s, size_t size, void **data)
{
  s->offset = (char *)data-(char *)s;
  *data = NULL;
  s->n = 0;
  s->alloc = 0;
  s->size = size;
}

inline void
stack_alloc(pari_stack *s, long nb)
{
  void **sdat = stack_base(s);
  if (s->n+nb <= s->alloc) return;
  if (!s->alloc)
    s->alloc = nb;
  else
  {
    while (s->n+nb > s->alloc) s->alloc <<= 1;
  }
  *sdat = pari_realloc(*sdat,s->alloc*s->size);
}

inline long
stack_new(pari_stack *s) { stack_alloc(s, 1); return s->n++; }

inline void
stack_pushp(pari_stack *s, void *u)
{
  long n = stack_new(s);
  void **sdat =(void**) *stack_base(s);
  sdat[n] = u;
}

static void ** MODULES, ** OLDMODULES;
static pari_stack s_MODULES, s_OLDMODULES;

void
pari_init_functions(void)
{
  stack_init(&s_MODULES, sizeof(*MODULES),(void**)&MODULES);
  stack_pushp(&s_MODULES,NULL);
  stack_init(&s_OLDMODULES, sizeof(*OLDMODULES),(void**)&OLDMODULES);
  stack_pushp(&s_OLDMODULES,NULL);
}

int main(void)
{
  pari_init_functions();
  return 0;
}