[llvm] [AMDGPU] Remove unnecessary add instructions in ctlz.i8 (PR #77615)

[Jay Foad via llvm-commits]

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@@ -3062,6 +3071,26 @@ static bool isCttzOpc(unsigned Opc) {
   return Opc == ISD::CTTZ || Opc == ISD::CTTZ_ZERO_UNDEF;
 }
 
+SDValue AMDGPUTargetLowering::lowerCTLZResults(SDValue Op,
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jayfoad wrote:

Nit: I know you've already changed the name once, but isn't this really doing integer result promotion (as in `DAGTypeLegalizer::PromoteIntegerResult`)? So maybe `PromoteIntRes_CTLZ`??

https://github.com/llvm/llvm-project/pull/77615