[PATCH] D127275: [MVE] Fold fadd(select(..., +0.0)) into a predicated fadd

[David Sherwood via Phabricator via llvm-commits]

david-arm added a comment.

In D127275#3566222 <https://reviews.llvm.org/D127275#3566222>, @spatel wrote:

> If this is inverting the transform from D126774 <https://reviews.llvm.org/D126774>, do we need 'nsz' to avoid miscompiling -0.0? 
> https://alive2.llvm.org/ce/z/Z6sngi

I'm assuming that for MVE an fadd of +0 for a given lane is equivalent to simply not performing the fadd for that lane (i.e. by using predication). This is the same assumption that we were making for -0 case, i.e. that adding either -0 or +0 leaves the lane unchanged. Perhaps @dmgreen can confirm this?


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https://reviews.llvm.org/D127275