[PATCH] D102893: [RISCV] Optimize xor/or with immediate in the zbs extension

Craig Topper via Phabricator via llvm-commits llvm-commits at lists.llvm.org
Thu May 20 20:57:53 PDT 2021


craig.topper added a comment.

My comment on the previous patch was about constants like 2051 that can be done with

ORI a0, 3
BSETI a0, 11

I don't think this patch handles that.



================
Comment at: llvm/test/CodeGen/RISCV/rv64zbs.ll:1426
 ; RV64IB:       # %bb.0:
-; RV64IB-NEXT:    lui a1, 2
-; RV64IB-NEXT:    addiw a1, a1, -2045
-; RV64IB-NEXT:    or a0, a0, a1
+; RV64IB-NEXT:    ori a0, a0, 3
+; RV64IB-NEXT:    bseti a0, a0, 11
----------------
This isn't really an improvement.


CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D102893/new/

https://reviews.llvm.org/D102893



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