Do not use TYPE_CANONICAL in useless_type_conversion

[Richard Biener]

On Tue, 13 Oct 2015, Alexandre Oliva wrote:

> On Oct  9, 2015, Jan Hubicka <hubicka@ucw.cz> wrote:
> 
> > ... we initialize mode to be non-VOIDmode only if the field is not bitfield. I missed
> > the flag while looking at the dump.  Indeed the DECL_MODE if FIELD_DECL is SImode,
> > but it is ignored.
> 
> > Hmm, it seems that for CALL_EXPR the register is supposed to be non-BLKmode
> > already.  So I guess only what we need to do is to consider bifields when 
> > TEMP is blk mode and then we want to convert? what about this?
> 
> How about using in store_bit_field the same logic you added to
> store_expr_with_bounds to get input MEMs to have a compatible mode?
> This patch was regstrapped on i686-linux-gnu and x86_64-linux-gnu.  Ok
> to install?

Ok.

Thanks,
Richard.

> support BLKmode inputs for store_bit_field
> 
> From: Alexandre Oliva <aoliva@redhat.com>
> 
> Revision 228586 changed useless_type_conversion_p and added mode
> changes for MEM:BLKmode inputs in store_expr_with_bounds, but it
> missed store_bit_field.  This caused ada/rts/s-regpat.ads to fail
> compilation on x86_64-linux-gnu.
> 
> for  gcc/ChangeLog
> 
> 	* expmed.c (store_bit_field_1): Adjust mode of BLKmode inputs.
> ---
>  gcc/expmed.c |    8 ++++++++
>  1 file changed, 8 insertions(+)
> 
> diff --git a/gcc/expmed.c b/gcc/expmed.c
> index 93cf508..69ea511 100644
> --- a/gcc/expmed.c
> +++ b/gcc/expmed.c
> @@ -757,6 +757,14 @@ store_bit_field_1 (rtx str_rtx, unsigned HOST_WIDE_INT bitsize,
>        }
>    }
>  
> +  /* We allow move between structures of same size but different mode.
> +     If source is in memory and the mode differs, simply change the memory.  */
> +  if (GET_MODE (value) == BLKmode && GET_MODE (op0) != BLKmode)
> +    {
> +      gcc_assert (MEM_P (value));
> +      value = adjust_address_nv (value, GET_MODE (op0), 0);
> +    }
> +
>    /* Storing an lsb-aligned field in a register
>       can be done with a movstrict instruction.  */
>  
> 
> 
> 

-- 
Richard Biener <rguenther@suse.de>
SUSE LINUX GmbH, GF: Felix Imendoerffer, Jane Smithard, Graham Norton, HRB 21284 (AG Nuernberg)