[llvm-dev] How to make the optimizer eliminate `fadd zeroinitializer`?

[Henning Thielemann via llvm-dev]

On Fri, 12 Aug 2016, escha at apple.com wrote:

> Adding ‘fast’ to the fadd should simplify it. Note that adding zero is 
> not a no-op in floating point arithmetic; adding negative zero is.

Ah, that is adding zero to negative zero is the corner case!

It seems that
   opt -enable-no-infs-fp-math  adds  ninf  globally
   opt -enable-no-nans-fp-math  adds  nnan  globally

but I do not see a counterpart for the flags 'nsz', 'arcp' and 'fast'. :-(