[PATCH] D131260: [DAG] select Cond, -1, C --> or (sext Cond), C if Cond is MVT::i1
Amaury SECHET via Phabricator via llvm-commits
llvm-commits at lists.llvm.org
Sat Aug 6 19:05:04 PDT 2022
deadalnix added inline comments.
================
Comment at: llvm/test/CodeGen/X86/select_const.ll:289
+; CHECK-NEXT: negl %eax
+; CHECK-NEXT: orl $3, %eax
; CHECK-NEXT: # kill: def $ax killed $ax killed $eax
----------------
deadalnix wrote:
> TODO: (sext Cond) | (Pow2 - 1) -> Pow2 - (zext (not Cond)) ?
>
> Maybe if inverting Cond if for free? Is there a way to check for this?
>
> Or maybe this is best reserved for `X86DAGToDAGISel::matchAddressRecursively`?
I meant (sext Cond) | (Pow2 - 1) -> (zext (not Cond)) * Pow2 - 1 ?
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https://reviews.llvm.org/D131260/new/
https://reviews.llvm.org/D131260
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