[PATCH] D131260: [DAG] select Cond, -1, C --> or (sext Cond), C if Cond is MVT::i1

[Amaury SECHET via Phabricator via llvm-commits]

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
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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