Re: [PATCH] Check SCALAR_INT_MODE_P in try_const_anchors

[Richard Biener <rguenther@suse.de>]

On Fri, 16 Jun 2023, Jiufu Guo wrote:

> Hi,
> 
> The const_anchor in cse.cc supports integer constants only.
> There is a "gcc_assert (SCALAR_INT_MODE_P (mode))" in
> try_const_anchors.
> 
> In the latest code, some non-integer modes are used with const int.
> For examples:
> "set (mem/c:BLK (xx) (const_int 0 [0])" occur in md files of
> rs6000, i386, arm, and pa. For this, the mode may be BLKmode.
> Pattern "(set (strict_low_part (xx)) (const_int xx))" could
> be generated in a few ports. For this, the mode may be VOIDmode.
> 
> So, avoid mode other than SCALAR_INT_MODE in try_const_anchors
> would be needed.
> 
> Some discussions in the previous thread:
> https://gcc.gnu.org/pipermail/gcc-patches/2023-June/621097.html
> 
> Bootstrap &regtest pass on ppc64{,le} and x86_64.
> Is this ok for trunk?

OK.

Richard.

> 
> BR,
> Jeff (Jiufu Guo)
> 
> gcc/ChangeLog:
> 
> 	* cse.cc (try_const_anchors): Check SCALAR_INT_MODE.
> 
> ---
>  gcc/cse.cc | 5 ++---
>  1 file changed, 2 insertions(+), 3 deletions(-)
> 
> diff --git a/gcc/cse.cc b/gcc/cse.cc
> index 2bb63ac4105..ddb76fd281d 100644
> --- a/gcc/cse.cc
> +++ b/gcc/cse.cc
> @@ -1312,11 +1312,10 @@ try_const_anchors (rtx src_const, machine_mode mode)
>    rtx lower_exp = NULL_RTX, upper_exp = NULL_RTX;
>    unsigned lower_old, upper_old;
>  
> -  /* CONST_INT is used for CC modes, but we should leave those alone.  */
> -  if (GET_MODE_CLASS (mode) == MODE_CC)
> +  /* CONST_INT may be in various modes, avoid non-scalar-int mode. */
> +  if (!SCALAR_INT_MODE_P (mode))
>      return NULL_RTX;
>  
> -  gcc_assert (SCALAR_INT_MODE_P (mode));
>    if (!compute_const_anchors (src_const, &lower_base, &lower_offs,
>  			      &upper_base, &upper_offs))
>      return NULL_RTX;
> 

-- 
Richard Biener <rguenther@suse.de>
SUSE Software Solutions Germany GmbH, Frankenstrasse 146, 90461 Nuernberg,
Germany; GF: Ivo Totev, Andrew Myers, Andrew McDonald, Boudien Moerman;
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