On Sun, 19 Apr 2020, Uros Bizjak wrote:
> This patch implements the idea from glibc, where generic division
> operations instead of assembly are used where appropriate.
>
> --commit--
> i386: Use generic division to generate INVALID and DIVZERO exceptions
>
> Introduce math_force_eval to evaluate generic division to generate
> INVALID and DIVZERO exceptions.
>
> libgcc/ChangeLog:
>
> 2020-04-19 Uroš Bizjak <ubiz...@gmail.com>
>
> * config/i386/sfp-exceptions.c (math_force_eval): New define.
> (__sfp_handle_exceptions): Use math_force_eval to evaluete
> generic division to generate INVALID and DIVZERO exceptions.
>
> libatomic/ChangeLog:
>
> 2020-04-19 Uroš Bizjak <ubiz...@gmail.com>
>
> * config/x86/fenv.c (math_force_eval): New define.
> (__atomic_feraiseexcept): Use math_force_eval to evaluete
> generic division to generate INVALID and DIVZERO exceptions.
>
> libgfortran/ChangeLog:
>
> 2020-04-19 Uroš Bizjak <ubiz...@gmail.com>
>
> * config/fpu-387.h (_math_force_eval): New define.
> (local_feraiseexcept): Use math_force_eval to evaluete
> generic division to generate INVALID and DIVZERO exceptions.
> --/commit--
>
> The patch was bootstrapped and regression tested on x86_64-linux-gnu
> {,-m32}. Also, as part of glibc's patch evaluation, I have extensively
> tested it to check that it really generates only correct exceptions
> for both, x87 and SSE math.
>
> Additionally, the patch improves code for DIVZERO exception, as we can
> now use FDIVRP mnemonic. This mnemonic has its own share of confusion
> (see e.g. SYSV386_COMPAT macro definition) and its use in asm should
> be avoided.
> --/commit message--
>
> The patch looks safe to me, but I'd like to ask RMs for approval.
If it doesn't fix a regression can it wait for stage1 please?
Thanks,
Richard.
