[PATCH] D115629: [RISCV] Use binvi and bexti to fold and (not (srl X, C)), 1

[Craig Topper via Phabricator via llvm-commits]

craig.topper added inline comments.


================
Comment at: llvm/lib/Target/RISCV/RISCVInstrInfoZb.td:795
+def : Pat<(and (not (srl GPR:$rs1, uimmlog2xlen:$shamt)), (XLenVT 1)),
+          (BEXTI (BINVI GPR:$rs1, uimmlog2xlen:$shamt),
+                 uimmlog2xlen:$shamt)>;
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I wonder if the (XORI (BEXTI GPR:$rs1, $shamt), 1) we would have gotten from the original InstCombine canonicalization would be better.

Guess it depends on whether the Zbs instructions are implemented as well as XORI or not. There is no c.xori or that would have been a good reason to favor xori.


Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D115629/new/

https://reviews.llvm.org/D115629