[llvm] [NVPTX] Avoid introducing unnecessary ProxyRegs and Movs in ISel (PR #120486)

[Artem Belevich via llvm-commits]

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@@ -212,21 +208,6 @@ bool NVPTXDAGToDAGISel::tryIntrinsicChain(SDNode *N) {
   }
 }
 
-// There's no way to specify FP16 and BF16 immediates in .(b)f16 ops, so we
-// have to load them into an .(b)f16 register first.
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Artem-B wrote:

I'm fine with removing this code as long as we can still handle constants correctly. This should already be covered by the original tests in llvm/test/CodeGen/NVPTX/f16-instructions.ll

https://github.com/llvm/llvm-project/pull/120486