[Bug ada/122063] unexpected overflow check before fixed-point multiplication

[cvs-commit at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=122063

--- Comment #2 from GCC Commits <cvs-commit at gcc dot gnu.org> ---
The master branch has been updated by Marc Poulhies <dkm@gcc.gnu.org>:

https://gcc.gnu.org/g:f714e1baf8804dfcff5bf9f23cd548c2c2e32a40

commit r16-4687-gf714e1baf8804dfcff5bf9f23cd548c2c2e32a40
Author: Eric Botcazou <ebotcazou@adacore.com>
Date:   Fri Sep 26 19:45:10 2025 +0200

    ada: Fix unexpected overflow check before fixed-point multiplication

    The problem is that the code generating the fixed-point multiply uses the
    subtypes of the operands to size the operation, while operations are to be
    performed in base types, which are signed per the RM 3.5.9(12) subclause.
    As a consequence, when the subtypes are fully asymmetric unsigned, the size
    is too small and an incorrect overflow check is generated.

    The code generating the divide was fixed a long time ago, this aligns the
    code generating the multiply and the code generating the remainder, which
    in turn requires a couple of adjustments to related routines.

    gcc/ada/ChangeLog:

            PR ada/122063
            * exp_fixd.adb (Build_Double_Divide_Code): Convert the result of
the
            multiply.
            (Build_Multiply): Use base types of operands to size the operation.
            (Build_Rem): Likewise.
            (Build_Scaled_Divide_Code): Convert the result of the multiply.