[PATCH] D93767: [RISCV] Legalize select when Zbt extension available

[Craig Topper via Phabricator via llvm-commits]

craig.topper added inline comments.


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Comment at: llvm/lib/Target/RISCV/RISCVInstrInfoB.td:780
           (CMIX GPR:$rs1, GPR:$rs2, GPR:$rs3)>;
-def : Pat<(riscv_selectcc GPR:$rs2, (XLenVT 0), (XLenVT 17), GPR:$rs3, GPR:$rs1),
+def : Pat<(select (XLenVT (setne GPR:$rs2, 0)), GPR:$rs1, GPR:$rs3),
+          (CMOV GPR:$rs1, GPR:$rs2, GPR:$rs3)>;
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mundaym wrote:
> craig.topper wrote:
> > Is there a difference between doing it this way versus just adding more riscv_selectcc patterns for other condition codes?
> No I think either would work. Using `riscv_selectcc` would have the advantage that we'd only encounter normalised condition codes so we'd need fewer patterns. Do you have a preference?
I think my preference is towards fewer patterns.


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  https://reviews.llvm.org/D93767/new/

https://reviews.llvm.org/D93767