[PATCH] D140319: [RISCV] Match neg (and x, 1) to two shifts to improve codesize

[Craig Topper via Phabricator via llvm-commits]

craig.topper added inline comments.


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Comment at: llvm/lib/Target/RISCV/RISCVInstrInfo.td:1244
+// is never compressible since rs1 and rd can't be the same register.
+let Predicates = [HasStdExtC] in {
+def : Pat<(XLenVT (sub 0, (and_oneuse GPR:$rs, 1))),
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Any harm in doing this regardless of HasStdExtC? I've sort of been of the opinion that we should avoid CodeGen differences between C and non-C if we can.


CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D140319/new/

https://reviews.llvm.org/D140319