[PATCH v1] Match: Allow more types truncation for .SAT_TRUNC

[Richard Biener]

On Tue, Jul 2, 2024 at 3:38 AM <pan2.li@intel.com> wrote:
>
> From: Pan Li <pan2.li@intel.com>
>
> The .SAT_TRUNC has the input and output types,  aka cvt from
> itype to otype and the sizeof (otype) < sizeof (itype).  The
> previous patch only allows the sizeof (otype) == sizeof (itype) / 2.
> But actually we have 1/4 and 1/8 truncation.
>
> This patch would like to support more types trunction when
> sizeof (otype) < sizeof (itype).  The below truncation will be
> covered.
>
> * uint64_t => uint8_t
> * uint64_t => uint16_t
> * uint64_t => uint32_t
> * uint32_t => uint8_t
> * uint32_t => uint16_t
> * uint16_t => uint8_t
>
> The below test suites are passed for this patch:
> 1. The rv64gcv fully regression tests.
> 2. The rv64gcv build with glibc.
> 3. The x86 bootstrap tests.
> 4. The x86 fully regression tests.

OK.

> gcc/ChangeLog:
>
>         * match.pd: Allow any otype is less than itype truncation.
>
> Signed-off-by: Pan Li <pan2.li@intel.com>
> ---
>  gcc/match.pd | 12 ++++++------
>  1 file changed, 6 insertions(+), 6 deletions(-)
>
> diff --git a/gcc/match.pd b/gcc/match.pd
> index 7fff7b5f9fe..f708f4622bd 100644
> --- a/gcc/match.pd
> +++ b/gcc/match.pd
> @@ -3239,16 +3239,16 @@ DEFINE_INT_AND_FLOAT_ROUND_FN (RINT)
>  (match (unsigned_integer_sat_trunc @0)
>   (bit_ior:c (negate (convert (gt @0 INTEGER_CST@1)))
>     (convert @0))
> - (with {
> + (if (INTEGRAL_TYPE_P (type) && TYPE_UNSIGNED (type)
> +      && TYPE_UNSIGNED (TREE_TYPE (@0)))
> + (with
> +  {
>     unsigned itype_precision = TYPE_PRECISION (TREE_TYPE (@0));
>     unsigned otype_precision = TYPE_PRECISION (type);
> -   wide_int trunc_max = wi::mask (itype_precision / 2, false, itype_precision);
> +   wide_int trunc_max = wi::mask (otype_precision, false, itype_precision);
>     wide_int int_cst = wi::to_wide (@1, itype_precision);
>    }
> -  (if (INTEGRAL_TYPE_P (type) && TYPE_UNSIGNED (type)
> -       && TYPE_UNSIGNED (TREE_TYPE (@0))
> -       && otype_precision < itype_precision
> -       && wi::eq_p (trunc_max, int_cst)))))
> +  (if (otype_precision < itype_precision && wi::eq_p (trunc_max, int_cst))))))
>
>  /* x >  y  &&  x != XXX_MIN  -->  x > y
>     x >  y  &&  x == XXX_MIN  -->  false . */
> --
> 2.34.1
>