[llvm] [AArch64] Add sve bf16 fpext and fpround costs. (PR #150485)

[Paul Walker via llvm-commits]

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@@ -3092,6 +3092,12 @@ InstructionCost AArch64TTIImpl::getCastInstrCost(unsigned Opcode, Type *Dst,
     return AdjustCost(
         BaseT::getCastInstrCost(Opcode, Dst, Src, CCH, CostKind, I));
 
+  // For the moment we do not have lowering for SVE1-only fptrunc f64->bf16 as
+  // we use fcvtx undef SVE2. Give them invalid costs.
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paulwalker-arm wrote:

s/undef/under/?

https://github.com/llvm/llvm-project/pull/150485