Re: [PATCH 1/2] Enable setting sign and unsigned promoted mode (SPR_SIGNED_AND_UNSIGNED)

[Jakub Jelinek <jakub at redhat dot com>]

On Wed, Jun 25, 2014 at 05:21:08PM +1000, Kugan wrote:
> The problem with SRP_POINTER 0, SRP_SIGNED 1, SRP_UNSIGNED 2,
> SRP_SIGNED_AND_UNSIGNED 3 (as I understand) is that, it will be
> incompatible with TYPE_UNSIGNED (tree) and defines of
> POINTER_EXTEND_UNSIGNED values. We will have to then translate while
> setting to SRP_* values . Also SUBREG_PROMOTED_SIGNED_P is now checked
> in some cases for != 0 (meaning SRP_POINTER or SRP_UNSIGNED) and in some
> cases > 0 (meaning SRP_UNSIGNED).
> 
> Since our aim is to perform single bit checks, why donât we just use
> this representation internally (i.e.  _rtx->unchanging = 1 if SRP_SIGNED
> and _rtx->volatil = 1 if SRP_UNSIGNED). As for SUBREG_PROMOTED_SIGNED_P,
> we still have to return -1 or 1 depending on SRP_POINTER or SRP_UNSIGNED.

Why don't you make SUBREG_PROMOTED_UNSIGNED_P just return 0/1 (i.e. the
single bit), and for places where it would like to match both
SRP_UNSIGNED and SRP_POINTER use SUBREG_PROMOTED_GET () & SRP_UNSIGNED
or so?

> --- a/gcc/ifcvt.c
> +++ b/gcc/ifcvt.c
> @@ -1448,8 +1448,11 @@ noce_emit_cmove (struct noce_if_info *if_info, rtx x, enum rtx_code code,
>  	  || byte_vtrue != byte_vfalse
>  	  || (SUBREG_PROMOTED_VAR_P (vtrue)
>  	      != SUBREG_PROMOTED_VAR_P (vfalse))
> -	  || (SUBREG_PROMOTED_UNSIGNED_P (vtrue)
> -	      != SUBREG_PROMOTED_UNSIGNED_P (vfalse)))
> +	  || ((SUBREG_PROMOTED_UNSIGNED_P (vtrue)
> +	       != SUBREG_PROMOTED_UNSIGNED_P (vfalse))
> +	      && (SUBREG_PROMOTED_SIGNED_P (vtrue)
> +		  != SUBREG_PROMOTED_SIGNED_P (vfalse))))

Shouldn't this be SUBREG_PROMOTED_GET (vtrue) != SUBREG_PROMOTED_GET (vfalse) ?

> +const unsigned int SRP_POINTER	= -1;
> +const unsigned int SRP_SIGNED   = 0;

Inconsistent whitespace, just use space instead of multiple spaces and/or
tabs.

> +const unsigned int SRP_UNSIGNED = 1;
> +const unsigned int SRP_SIGNED_AND_UNSIGNED = 2;

> +/* Predicate to check if RTX of SUBREG_PROMOTED_VAR_P() is promoted
> +   for SIGNED type.  */
> +#define SUBREG_PROMOTED_SIGNED_P(RTX)	\
> +  (RTL_FLAG_CHECK1 ("SUBREG_PROMOTED_SIGNED_P", (RTX), SUBREG)->unchanging == 1)

Why the " == 1" ?
> +
> +/* Predicate to check if RTX of SUBREG_PROMOTED_VAR_P() is promoted
> +   for UNSIGNED type.  In case of SRP_POINTER, SUBREG_PROMOTED_UNSIGNED_P
> +   returns -1 as this is in most cases handled like unsigned extension,
> +   except for generating instructions where special code is emitted for
> +   (ptr_extend insns) on some architectures.  */
>  #define SUBREG_PROMOTED_UNSIGNED_P(RTX)	\
> -  ((RTL_FLAG_CHECK1 ("SUBREG_PROMOTED_UNSIGNED_P", (RTX), SUBREG)->volatil) \
> -   ? -1 : (int) (RTX)->unchanging)
> +  ((((RTL_FLAG_CHECK1 ("SUBREG_PROMOTED_UNSIGNED_P", (RTX), SUBREG)->volatil)\
> +     + (RTX)->unchanging) == 0) ? -1 : ((RTX)->volatil == 1))
> +
> +/* Checks if RTX of SUBREG_PROMOTED_VAR_P() is promotd for given SIGN.  */
> +#define	SUBREG_CHECK_PROMOTED_SIGN(RTX, SIGN) \

Use space rather than tab.  Also, why do we need this macro?
Can't you just use SUBREG_PROMOTED_GET () == sign ?  I mean, sign in that
case is typically just 0 or 1.

	Jakub