[Bug target/85669] fail on s-case-cfn-macros: build/gencfn-macros: DEF_INTERNAL_FLT/INT_FN (%smth%) has no associated built-in functions

[wilco at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=85669

--- Comment #52 from Wilco <wilco at gcc dot gnu.org> ---
(In reply to Segher Boessenkool from comment #50)
> The generic code rounded up the allocation size twice, and that isn't needed.
> 
> The problem has been solved for other targets before; a patch for Darwin is
> at https://gcc.gnu.org/ml/gcc-testresults/2017-01/msg02971.html , patch 0001.

Yes that looks correct indeed. No idea why it wasn't committed... It looks like
the patch in comment 16 didn't work because rs6000_stack_info does its own
calculation of this, so aligning when alloca isn't used will get incorrect
frame offsets:

  info->fixed_size   = RS6000_SAVE_AREA;
  info->vars_size    = RS6000_ALIGN (get_frame_size (), 8);
  if (cfun->calls_alloca)
    info->parm_size  =
      RS6000_ALIGN (crtl->outgoing_args_size + info->fixed_size,
                    STACK_BOUNDARY / BITS_PER_UNIT) - info->fixed_size;
  else
    info->parm_size  = RS6000_ALIGN (crtl->outgoing_args_size,
                                     TARGET_ALTIVEC ? 16 : 8);