[cfe-dev] fp-contract at -O0

David Greene via cfe-dev cfe-dev at lists.llvm.org
Wed Feb 19 09:22:40 PST 2020


Stephen Canon <scanon at apple.com> writes:

>> On Feb 18, 2020, at 2:01 PM, David Greene <greened at obbligato.org> wrote:
>> 
>> There are many cases where FMA is not desired and most users don't
>> expect fused operations at -O0 unless they specifically ask for it.
>
> If FMA is not desired, -ffp-contract=off or the pragma should be used
> to disable it. -O0 is the wrong tool for that job.

Why?  Many of our customers would be surprised to see FMAs at -O0.

                   -David


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