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Re: [PATCH] Change default to -fno-math-errno
- From: Wilco Dijkstra <Wilco dot Dijkstra at arm dot com>
- To: Joseph Myers <joseph at codesourcery dot com>
- Cc: Richard Biener <richard dot guenther at gmail dot com>, GCC Patches <gcc-patches at gcc dot gnu dot org>, nd <nd at arm dot com>
- Date: Tue, 7 Nov 2017 15:09:48 +0000
- Subject: Re: [PATCH] Change default to -fno-math-errno
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Joseph Myers wrote:
On Mon, 30 Oct 2017, Wilco Dijkstra wrote:
> The semantics of __*_finite definitely include finite-math-only, as they
> aren't all just disabling the wrappers (e.g. sysdeps/i386/i686/fpu/e_log.S
> has __log_finite separate from __ieee754_log).
I only see a few cases where there are separate __ieee754 and finite
implementations - all seem to be x87 assembler. I don't think the existence
of a few special cases should block the simple optimization of avoiding the
wrappers when reasonable.
For example if removing/merging the x87 implementations is unacceptable,
the header could use -ffinite-math-only for x86/x64 but use -fno-math-errno
on all other targets.
Wilco