[PATCH] D150670: [WebAssembly] Disable generation of fshl/fshr for rotates

Paulo Matos via Phabricator via cfe-commits cfe-commits at lists.llvm.org
Fri May 26 07:00:32 PDT 2023


pmatos added inline comments.


================
Comment at: llvm/test/Transforms/InstCombine/fsh.ll:664
+; CHECK-NEXT:    [[T1:%.*]] = and i32 [[A:%.*]], -65536
+; CHECK-NEXT:    [[T2:%.*]] = call i32 @llvm.fshl.i32(i32 [[T1]], i32 [[T1]], i32 16)
 ; CHECK-NEXT:    ret i32 [[T2]]
----------------
nikic wrote:
> We still want to simplify this case. Could possibly be done by checking whether all demanded bits are zero for one of the operands in the rotate case.
Ah, yes,  right. That should be just a simple shift right. Will see how to still allow that change. Thanks.


Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D150670/new/

https://reviews.llvm.org/D150670



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