[Bug ipa/63571] New: Local functions with only local aliases not regparm optimized on i686-linux

[jakub at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=63571

            Bug ID: 63571
           Summary: Local functions with only local aliases not regparm
                    optimized on i686-linux
           Product: gcc
           Version: 5.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: ipa
          Assignee: unassigned at gcc dot gnu.org
          Reporter: jakub at gcc dot gnu.org
                CC: hubicka at gcc dot gnu.org, jakub at gcc dot gnu.org,
                    jakub at redhat dot com, mliska at suse dot cz, uros at gcc 
dot gnu.org
        Depends on: 63566

+++ This bug was initially created as a clone of Bug #63566 +++

#define A \
  x += y * z; \
  y = (y << ((z & 2) + 1)) \
      ^ (y >> (__SIZEOF_INT__ * __CHAR_BIT__ - (z & 2) - 1)); \
  z *= 7;
#define B A A A A A A A A A A
#define C B B B B B B B B B B

static unsigned int
f2 (unsigned int x, unsigned int y, unsigned int z)
{
  C
  return x + y + z;
}

static __typeof (f2) f1 __attribute__((alias ("f2")));

__attribute__((noinline, noclone)) unsigned int
f3 (unsigned int x, unsigned int y, unsigned int z)
{
  return f1 (x, z, y) + 6;
}

__attribute__((noinline, noclone)) unsigned int
f4 (unsigned int x, unsigned int y, unsigned int z)
{
  return f2 (y, x, z) + 7;
}

__attribute__((noinline, noclone, used)) unsigned int
f5 (unsigned int x, unsigned int y, unsigned int z)
{
  return f1 (2 * x, z / 2, y + 3) - 6;
}

__attribute__((noinline, noclone, used)) unsigned int
f6 (unsigned int x, unsigned int y, unsigned int z)
{
  return f2 (y + 2, x | 1, z / 73) + 1;
}

int
main ()
{
  unsigned int x = f3 (0x173214, 0x182172, 0x9314);
  unsigned int y = f4 (0x173214, 0x182172, 0x9314);
#if __SIZEOF_INT__ * __CHAR_BIT__ == 32
  if (x != 0xd8e56f78U || y != 0x494c6699U)
    __builtin_abort ();
#endif
  return 0;
}

on i?86 -m32 -O2 doesn't use regparm calling convention for f1/f2, because f2
has alias, but as all the aliases are local too, there is no reason why it
couldn't be optimized too.

And the PR63566 testcase should for ICF merging use local regparm calling
convention too.