[PATCH] D70426: [DAGCombiner][RISCV] Avoid FCOPYSIGN folding of legalizing operand casts

[Alex Bradbury via Phabricator via llvm-commits]

asb added inline comments.


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Comment at: llvm/lib/Target/RISCV/RISCVInstrInfoD.td:234
 def : Pat<(fcopysign FPR64:$rs1, (fneg FPR64:$rs2)), (FSGNJN_D $rs1, $rs2)>;
+def : Pat<(fcopysign FPR64:$rs1, FPR32:$rs2), (FSGNJ_D $rs1, (FCVT_D_S $rs2))>;
+def : Pat<(fcopysign FPR32:$rs1, FPR64:$rs2), (FSGNJ_S $rs1, (FCVT_S_D $rs2, 0b111))>;
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luismarques wrote:
> lenary wrote:
> > Please can you add a comment to note that these patterns will eventually not be needed, once we improve fcopysign handling?
> Although that was my original plan, there doesn't seem to be review consensus yet that such changes will be coming and accepted. (If only this patch was committed we would be left at a reasonable place, even if not perfect.)
I take your point about not wanting to describe future plans where there might not be consensus. I'd put a brief sentence like "These patterns can be removed if..."


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  https://reviews.llvm.org/D70426/new/

https://reviews.llvm.org/D70426