[PATCH] D155328: [RISCV] Add a DAG combine for (czero_eq X, (xor Y, 1)) -> (czero_ne X, Y) if Y is 0 or 1.

[Craig Topper via Phabricator via llvm-commits]

craig.topper added inline comments.


================
Comment at: llvm/lib/Target/RISCV/RISCVISelLowering.cpp:12728
+    return SDValue();
+
   case RISCVISD::SELECT_CC: {
----------------
craig.topper wrote:
> mgudim wrote:
> > Why not express this using pattern?
> I'm not sure what you mean.
Do you mean an isel pattern in tablegen? I'd need a PatFrag or ComplexPattern to call MaskValueIsZero. So there doesn't seem to be any advantage.


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  https://reviews.llvm.org/D155328/new/

https://reviews.llvm.org/D155328