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

Matt Arsenault via Phabricator via llvm-commits llvm-commits at lists.llvm.org
Mon Mar 20 20:43:37 PDT 2017


arsenm 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).
+
----------------
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.


https://reviews.llvm.org/D31164





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