[PATCH] D85548: Allow fneg + strict_fadd -> strict_fsub in DAGCombiner

[Matt Arsenault via Phabricator via llvm-commits]

arsenm added a comment.

In D85548#2223906 <https://reviews.llvm.org/D85548#2223906>, @spatel wrote:

> Why wait until codegen to do this? IIUC, it's impossible for any backend to spontaneously create strict FP ops, so this pattern must be present in the original IR.
> Ie, wouldn't we be better off reducing these in IR (InstCombinerImpl::visitCallInst())?

It doesn't matter if instcombine does this or not, this pattern could still easily appear after legalization


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https://reviews.llvm.org/D85548