Re: [PATCH 1/2][AArch64] Implement AAPCS64 updates for alignment attribute

[James Greenhalgh <james.greenhalgh@arm.com>]

On Fri, Jan 22, 2016 at 05:16:00PM +0000, Alan Lawrence wrote:
> 
> On 21/01/16 17:23, Alan Lawrence wrote:
> > On 18/01/16 17:10, Eric Botcazou wrote:
> >>
> >> Could you post the list of files that differ?  How do they differ exactly?
> >
> > Hmmm. Well, I definitely had this failing to bootstrap once. I repeated that, to
> > try to identify exactly what the differences were....and it succeeded even with
> > my pre-AAPCS64-update host compiler. So, this is probably a false alarm; I'm
> > bootstrapping again, after a rebase, to make sure...
> >
> > --Alan
> 
> Ok, rebased onto a more recent build, and bootstrapping with Ada posed no
> problems. Sorry for the noise.
> 
> However, I had to drop the assert that TYPE_FIELDS was non-null because of some
> C++ testcases.
> 
> Is this version OK for trunk?

Now that we're in GCC7, this version of the patch is OK for trunk.

From my reading of Richard's AAPCS update, this patch implements the
rules as required.

I'll give this a day for any last minute comments from Richard/Marcus,
then commit this on your behalf tomorrow.

Thanks,
James

> gcc/ChangeLog:
> 
> 	* gcc/config/aarch64/aarch64.c (aarch64_function_arg_alignment):
> 	Rewrite, looking one level down for records and arrays.
> ---
>  gcc/config/aarch64/aarch64.c | 31 ++++++++++++++++---------------
>  1 file changed, 16 insertions(+), 15 deletions(-)
> 
> diff --git a/gcc/config/aarch64/aarch64.c b/gcc/config/aarch64/aarch64.c
> index 9142ac0..b084f83 100644
> --- a/gcc/config/aarch64/aarch64.c
> +++ b/gcc/config/aarch64/aarch64.c
> @@ -1925,22 +1925,23 @@ aarch64_vfp_is_call_candidate (cumulative_args_t pcum_v, machine_mode mode,
>  static unsigned int
>  aarch64_function_arg_alignment (machine_mode mode, const_tree type)
>  {
> -  unsigned int alignment;
> +  if (!type)
> +    return GET_MODE_ALIGNMENT (mode);
> +  if (integer_zerop (TYPE_SIZE (type)))
> +    return 0;
>  
> -  if (type)
> -    {
> -      if (!integer_zerop (TYPE_SIZE (type)))
> -	{
> -	  if (TYPE_MODE (type) == mode)
> -	    alignment = TYPE_ALIGN (type);
> -	  else
> -	    alignment = GET_MODE_ALIGNMENT (mode);
> -	}
> -      else
> -	alignment = 0;
> -    }
> -  else
> -    alignment = GET_MODE_ALIGNMENT (mode);
> +  gcc_assert (TYPE_MODE (type) == mode);
> +
> +  if (!AGGREGATE_TYPE_P (type))
> +    return TYPE_ALIGN (TYPE_MAIN_VARIANT (type));
> +
> +  if (TREE_CODE (type) == ARRAY_TYPE)
> +    return TYPE_ALIGN (TREE_TYPE (type));
> +
> +  unsigned int alignment = 0;
> +
> +  for (tree field = TYPE_FIELDS (type); field; field = DECL_CHAIN (field))
> +    alignment = std::max (alignment, DECL_ALIGN (field));
>  
>    return alignment;
>  }
> -- 
> 1.9.1
>