Re: [PATCH] tree-optimization/117912 - bogus address equivalences for __builtin_object_size

[Jakub Jelinek]

On Thu, Dec 05, 2024 at 11:37:45AM +0100, Richard Biener wrote:
>       * c-c++-common/torture/pr117912-1.c: New testcase.
>       * c-c++-common/torture/pr117912-2.c: Likewise.
>       * gcc.dg/torture/pr117912-3.c: Likewise.

Thanks for the patch.
I'd certainly suggest to replace the third test with
        * c-c++-common/torture/pr117912-3.c
with following because the test from the PR is just way too ugly and
doesn't really test much the __bos value at all, just that it is non-zero
and in a very weird way.  As for the sccvn change, I'd like to play with it
a little bit first if you don't mind.

/* { dg-do run } */

struct B {};
struct A { int a; struct B b; char c[]; };
volatile void *p;

void __attribute__((noipa))
bar (void *q)
{
  p = q;
}

__SIZE_TYPE__ __attribute__((noipa))
foo (struct A *p)
{
  bar (&p->b);
  bar (&p->c);
  return __builtin_object_size (&p->c, 1);
}

__SIZE_TYPE__ __attribute__((noipa))
baz (int x)
{
  struct A *p = x ? __builtin_malloc (__builtin_offsetof (struct A, c) + 64)
                  : __builtin_calloc (__builtin_offsetof (struct A, c) + 32, 1);
  bar (&p->b);
  bar (&p->c);
  return __builtin_object_size (&p->c, 1);
}

__SIZE_TYPE__ __attribute__((noipa))
qux (struct A *p)
{
  bar (&p->b);
  bar (&p->c);
  return __builtin_object_size (&p->c, 3);
}

__SIZE_TYPE__ __attribute__((noipa))
boo (int x)
{
  struct A *p = x ? __builtin_malloc (__builtin_offsetof (struct A, c) + 64)
                  : __builtin_calloc (__builtin_offsetof (struct A, c) + 32, 1);
  bar (&p->b);
  bar (&p->c);
  return __builtin_object_size (&p->c, 3);
}

int
main ()
{
  static struct A a = { .a = 1, .b = {}, .c = { 1, 2, 3, 4, 0 } };
  if (foo (&a) < 5)
    __builtin_abort ();
  if (baz (0) < 64)
    __builtin_abort ();
  if (qux (&a) != 0)
    __builtin_abort ();
  if (boo (0) > 32)
    __builtin_abort ();
}

        Jakub