Re: [PATCH 0/3] ARM with only 32-bit floats do not have fast 64-bit FMA
Keith Packard via Newlib <[email protected]>
| Newsgroups | gmane.comp.lib.newlib |
|---|---|
| Message-ID | <[email protected]> |
Brian Inglis <[email protected]> writes: > Can't the "super-smart" compiler use that information to work around your > careful approach by conditionally skipping the FMA and conditionally return just > z, or even unconditionally return z, as C makes no guarantees? > And couldn't the "super-smart" instruction scheduler do similar at the hardware > level? I don't think that would be in conformance with the C specification which says that arithmetic follows IEC 60559 that defines the various exceptions and results. Now, if you enable -ffast-math, all bets are off... -- -keith
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