[PATCH] D31164: [IR] Add AllowContract to FastMathFlags

[Adam Nemet via Phabricator via llvm-commits]

anemet added inline comments.


================
Comment at: docs/LangRef.rst:2197-2200
+``contract``
+   Allow floating-point contraction (e.g. fusing a multiply followed by an
+   addition into a fused multiply-and-add).
+
----------------
arsenm wrote:
> mehdi_amini wrote:
> > arsenm wrote:
> > > Should we also have an unsafe algebra that preserves signed zeros/nans etc?
> > @arsenm : isn't it the default when there is no `nsz` or `nnan` ?
> > 
> > 
> No, that is normal safe math. I mean unsafe algebraic transformations similar to contraction which will preserve nan/signed zeros/inf behavior but are still not safe.
Maybe but we may want that separate from contraction where the result is more exact.


https://reviews.llvm.org/D31164