Re: patch to fix PR65648

[Jakub Jelinek <jakub@redhat.com>]

On Tue, Apr 07, 2015 at 11:01:59AM -0400, Vladimir Makarov wrote:
> 2015-04-07  Vladimir Makarov  <vmakarov@redhat.com>
> 
>         PR target/65678
>         * lra-remat.c (do_remat): Process input and non-input insn
>         registers separately.

Don't have a quick access to arm box right now (without waiting for it to be
installed etc.), but using a cross-compiler I can at least reproduce
that your patch changes also:

/* PR target/65648 */

int a = 0, *b = 0, c = 0;
static int d = 0;
short e = 1;
static long long f = 0;
long long *i = &f;
unsigned char j = 0;

__attribute__((noinline, noclone)) void
foo (int x, int *y)
{
  asm volatile ("" : : "r" (x), "r" (y) : "memory");
}

__attribute__((noinline, noclone)) void
bar (const char *x, long long y)
{
  asm volatile ("" : : "r" (x), "r" (&y) : "memory");
  if (y != 0)
    __builtin_abort ();
}

int
main ()
{
  int k = 0;
  b = &k;
  j = (!a) - (c <= e);
  *i = j;
  foo (a, &k);
  bar ("", f);
  return 0;
}

so, if anybody can confirm this testcase aborts with -march=armv6-m -mthumb -Os
before Vlad's patch and doesn't abort afterwards, perhaps just sticking
that into gcc.c-torture/execute/pr65648.c would be sufficient.
Or, if people don't regularly test with -march=armv6-m -mthumb combination,
perhaps put it into gcc.c-torture/execute/pr65648.c as is and
add another gcc.target/arm/pr65648.c testcase that will #include this one,
and use the right dg-options / dg-skip-if or dg-require-effective-target etc.
for it to trigger.  As the testcase uses uninitialized r3 in the wrong case,
I wonder if the usual _start initializes r3 to some value that triggers the abort
without the fix; if not, perhaps it needs to be in another function and the caller
should somehow attempt to set l3 somehow (pass arguments to another function etc.)
to a value that will trigger the abort.

	Jakub