[llvm] [X86] Narrow vXi32/vXi64 usubsat to vpsubusb/vpsubusw when LHS is known to fit in fewer bits (PR #206592)

[Simon Pilgrim via llvm-commits]

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@@ -2074,6 +2074,7 @@ X86TargetLowering::X86TargetLowering(const X86TargetMachine &TM,
       setOperationAction(ISD::ROTR,             VT, Legal);
       setOperationAction(ISD::ABS,              VT, Legal);
       setOperationAction(ISD::CTPOP,            VT, Custom);
+      setOperationAction(ISD::USUBSAT, VT, Custom);
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RKSimon wrote:

drop this?

https://github.com/llvm/llvm-project/pull/206592