[llvm-dev] [FPEnv] FNEG instruction

[Stephen Canon via llvm-dev]

> On Aug 29, 2018, at 1:22 PM, Cameron McInally via llvm-dev <llvm-dev at lists.llvm.org> wrote:
> 
> FSUB(-0.0,  NaN) = NaN
> FSUB(-0.0, -NaN) = NaN

Some specific architecture may define this, or APFloat might, but IEEE 754 does not interpret the sign of NaN except in four operations (copy, abs, negate, copysign), so it doesn’t say anything about these.

– Steve
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