[llvm] [LLVM][CodeGen][SVE] Add lowering for ISD::[ANY,SIGN,ZERO]_EXTEND_VECTOR_INREG. (PR #169847)

[David Sherwood via llvm-commits]

================
@@ -14688,6 +14695,40 @@ static SDValue tryToConvertShuffleOfTbl2ToTbl4(SDValue Op,
                       Tbl2->getOperand(1), Tbl2->getOperand(2), TBLMask});
 }
 
+SDValue
+AArch64TargetLowering::LowerEXTEND_VECTOR_INREG(SDValue Op,
----------------
david-arm wrote:

nit: It's a minor thing, but we already have a LowerZERO_EXTEND_VECTOR_INREG, so at first it confused me a little why this was named as if it handles all extends. Then I realised it does handle all extends for scalable vectors only. I realise it's a bit verbose, but is it worth making it clear this is for scalable vectors only? For example, something like `LowerSCALABLE_EXTEND_VECTOR_INREG`?

https://github.com/llvm/llvm-project/pull/169847