[llvm] [RISCV][GISEL] Add legalizer for G_BSWAP (PR #70226)

[Craig Topper via llvm-commits]

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@@ -68,77 +68,32 @@ body:             |
     ; CHECK-NEXT: {{  $}}
     ; CHECK-NEXT: [[COPY:%[0-9]+]]:_(s32) = COPY $x10
     ; CHECK-NEXT: [[COPY1:%[0-9]+]]:_(s32) = COPY $x11
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topperc wrote:

I think it looks ok.

I see that we AND before SHL and after LSHR. That allows us to use the same AND mask twice. SelectionDAG used to use two different constants, but was fixed here https://reviews.llvm.org/D138045

You can use -start-before=legalizer to run all the way to assembly. The comparison with the SelectionDAG output will still require some hand analysis.



https://github.com/llvm/llvm-project/pull/70226