Thanks Pinski for comment.

> An unchecked use of tree_to_uhwi. Please add `tree_fits_uhwi_p (@2)`
> to the first if.

Make sense, let me go through the previous usage of this and adjust the series 
as well in V2.

Pan


-----Original Message-----
From: Andrew Pinski <[email protected]> 
Sent: Wednesday, June 17, 2026 9:31 AM
To: Li, Pan2 <[email protected]>
Cc: [email protected]; [email protected]; [email protected]; 
[email protected]; [email protected]; Chen, Ken <[email protected]>; 
Liu, Hongtao <[email protected]>; [email protected]
Subject: Re: [PATCH v1 1/2] Match: Support unsigned scalar SAT_MUL form 13

On Tue, Jun 16, 2026 at 12:32 AM <[email protected]> wrote:
>
> From: Pan Li <[email protected]>
>
> This patch would like to try to match the the unsigned
> SAT_MUL form 13, aka below
>
>   #define DEF_SAT_U_MUL_FMT_13(NT, WT)             \
>   NT __attribute__((noinline))                     \
>   sat_u_mul_##NT##_from_##WT##_fmt_13 (NT a, NT b) \
>   {                                                \
>     WT x = (WT)a * (WT)b;                          \
>     if ((x >> sizeof(a) * 8) != 0)                 \
>       return (NT)-1;                               \
>     else                                           \
>       return (NT)x;                                \
>   }
>
> while WT is uint128_t, uint64_t, uint32_t and uint16_t, and
> NT is uint64_t, uint32_t, uint16_t or uint8_t.
>
> gcc/ChangeLog:
>
>         * match-sat-alu.pd: Add pattern for unsigned scalar
>         SAT_MUL form 13.
>
> Signed-off-by: Pan Li <[email protected]>
> ---
>  gcc/match-sat-alu.pd | 25 +++++++++++++++++++++++++
>  1 file changed, 25 insertions(+)
>
> diff --git a/gcc/match-sat-alu.pd b/gcc/match-sat-alu.pd
> index 6145a0c9948..1f27817a6c0 100644
> --- a/gcc/match-sat-alu.pd
> +++ b/gcc/match-sat-alu.pd
> @@ -524,6 +524,31 @@ along with GCC; see the file COPYING3.  If not see
>        bool c2_is_type_precision_p = c2 == prec;
>       }
>       (if (widen_prec > prec && c2_is_type_precision_p && c4_is_max_p)))))
> +  (match (unsigned_integer_sat_mul @0 @1)
> +   /* SAT_U_MUL (X, Y) = {
> +       WT x = (WT)a * (WT)b;
> +       if ((x >> sizeof(a) * 8) != 0)
> +         return (T)-1;
> +       else
> +         return (T)x;
> +      }
> +      while WT is uint128_t, T is uint8_t, uint16_t, uint32_t or uint64_t.  
> */
> +   (convert (cond^ (ne (rshift (mult:c@3 (convert @0) (convert @1))
> +                              INTEGER_CST@2)
> +                      integer_zerop)
> +                  INTEGER_CST@4 @3))
> +   (if (types_match (type, @0, @1))
> +    (with
> +     {
> +      unsigned prec = TYPE_PRECISION (type);
> +      unsigned widen_prec = TYPE_PRECISION (TREE_TYPE (@3));
> +      wide_int c4 = wi::to_wide (@4);
> +      wide_int max = wi::mask (prec, false, widen_prec);
> +      bool c4_is_max_p = wi::eq_p (c4, max);
> +      unsigned c2 = tree_to_uhwi (@2);

An unchecked use of tree_to_uhwi. Please add `tree_fits_uhwi_p (@2)`
to the first if.
I noticed it on the other patterns in match-sat-alu.pd too. Maybe the
issue with using it unconditionally here won't hit any more but I am
not 100% sure.

Thanks,
Andrea


> +      bool c2_is_type_precision_p = c2 == prec;
> +     }
> +     (if (widen_prec > prec && c2_is_type_precision_p && c4_is_max_p)))))
>    (match (unsigned_integer_sat_mul @0 @1)
>     /* SAT_U_MUL (X, Y) = {
>         WT x = (WT)a * (WT)b;
> --
> 2.43.0
>

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