optimizer problem in linux-mips gcc-3.2?

[Guido Guenther <agx at sigxcpu dot org>]

Hi,
glibc's string/tester and string/inl-tester fail when compiled with
Debian's "gcc version 3.2.2 20030109 (Debian prerelease)" on linux-mips
(big endian) and -O2 or -Os. I've tried to strip down the testcase as
far as possible and suspect that gcc miscompiles it. It works fine with
Debian's "gcc version 2.95.4 20011002" and with the above gcc-3.2.2 and
optimations turned off, -O3 and -O1:

foo@bar:~$ gcc --save-temps -O2 tester.c && ./a.out
memccpy flunked test 8
0x10000100 is abcdefghr should be abcdefgh
1 errors.

foo@bar:~$ gcc --save-temps -Os tester.c && ./a.out 
memccpy flunked test 8
0x10000100 is abcdefghr should be abcdefgh
1 errors.

foo@bar:~$ gcc --save-temps -O3 tester.c && ./a.out 
0x10000100 is abcdefgh should be abcdefgh
No errors.

foo@bar:~$ gcc --save-temps -O0 tester.c && ./a.out 
0x10000100 is abcdefgh should be abcdefgh
No errors.

foo@bar:~$ gcc -O1 tester.c && ./a.out 
0x100000f0 is abcdefgh should be abcdefgh
No errors.

I've attache the testcase and the assembler output for -O2. Any help
greatly appreciated.
Regards,
 -- Guido
#ifndef _GNU_SOURCE
#define _GNU_SOURCE
#endif

/* Make sure we don't test the optimized inline functions if we want to
   test the real implementation.  */
#if !defined DO_STRING_INLINES
#undef __USE_STRING_INLINES
#endif

#include <errno.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#ifndef HAVE_GNU_LD
#define _sys_nerr	sys_nerr
#define _sys_errlist	sys_errlist
#endif

#define	STREQ(a, b)	(strcmp((a), (b)) == 0)

const char *it = "memccpy";	/* Routine name for message routines. */
size_t errors = 0;

/* Complain if condition is not true.  */
static void
check (int thing, int number)
{
  if (!thing)
    {
      printf("flunked test %d\n", number);
      ++errors;
    }
}

/* Complain if first two args don't strcmp as equal.  */
static void
equal (const char *a, const char *b, int number)
{
  check(a != NULL && b != NULL && STREQ (a, b), number);
}

char one[50];
char two[50];

static void
test_memccpy (void)
{
  (void) strcpy(one, "abcdefgh");
  (void) strcpy(two, "horsefeathers");
  check(memccpy(two, one, 'f', 9) == two+6, 7);	/* Returned value. */
  equal(one, "abcdefgh", 8);		/* Source intact? */
  printf("%p is %s should be abcdefgh\n", one, one);
  equal(two, "abcdefeathers", 9);		/* Copy correct? */
}

int
main (void)
{
  int status;

  /* memccpy.  */
  test_memccpy ();

  if (errors == 0)
    {
      status = EXIT_SUCCESS;
      puts("No errors.");
    }
  else
    {
      status = EXIT_FAILURE;
      printf("%Zd errors.\n", errors);
    }

  return status;
}

Attachment: tester-O2.s
Description: Text document