[Bug libgcc/59714] complex division is surprising on targets with FMA (was: on aarch64)

[patrick.mcgehearty at oracle dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=59714

Patrick McGehearty <patrick.mcgehearty at oracle dot com> changed:

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--- Comment #9 from Patrick McGehearty <patrick.mcgehearty at oracle dot com> ---
The patch 54f0224d55a1b56dde092460ddf76913670e6efc
"Practical improvement to libgcc complex divide"
made substantial improvements to the algorithms
used and thus the accuracy of complex divide for
IEEE-754 precisions for half, float, double, and
long-double precision.

In particular, when examining randomly generated
values uniformly distributed over the full exponent
range, 2 bit errors dropped from 1.88% to less than
one in 10,000. The particular input values discussed
in this problem report no longer show any errors
whether or not FMA is used.

See the patch for more complete details.