Re: [PATCH, fortran] PR93727 Implement new EX format specifier

On Mon, May 25, 2026 at 3:16 AM Jerry D <[email protected]> wrote:
>
> On 5/24/26 12:38 AM, H.J. Lu wrote:
> > Note: The following floating-point exceptions are signalling:
> > IEEE_INVALID_FLAG IEEE_UNDERFLOW_FLAG IEEE_DENORMAL
> > STOP 3
> > FAIL: gfortran.dg/EXformat_1.F90   -O0  execution test
>
> I fed the above and the CI report I received to Claude and it
> arrived at the attached patch rather quickly.  Can you try this and confirm
> whether it fixes it or not?

Yes, it works.

Thanks.

> Regards,
>
> Jerry
>
> ---------------
>
>  From 837ca2b4c3d1069ddb938a5a7c259d34a85479fc Mon Sep 17 00:00:00 2001
> From: Jerry DeLisle <[email protected]>
> Date: Sun, 24 May 2026 11:51:49 -0700
> Subject: [PATCH] Fortran: [PR93727] Fix EX format kind=8 output on ILP32
>   targets
>
> On 32-bit targets such as ARM where unsigned long is 32 bits, the
> kind=8 case in get_float_hex_string used unsigned long for frac_part.
> The kind=8 mantissa requires 52 bits (13 hex digits), so the cast
> silently truncated the upper bits, producing wrong hex output.  In
> addition, converting a ~4.5e15 double value to a 32-bit unsigned long
> is out of range, which raised IEEE_INVALID_FLAG on ARM hardware.
>
> The kind=10 case already used unsigned long long for the same reason.
> Fix kind=8 to match: change the type, the cast, and the two %lX
> format specifiers to %llX.
>
>         PR fortran/93727
>
> libgfortran/ChangeLog:
>
>         * io/write_float.def (get_float_hex_string): Change frac_part
>         for kind=8 from unsigned long to unsigned long long and update
>         format specifiers from %13.13lX to %13.13llX to fix truncated
>         hex output and IEEE_INVALID_FLAG on ILP32 targets.
>
> Assisted by: Claude Sonnet 4.6
>


-- 
H.J.