[llvm] [AMDGPU][True16][CodeGen] Implement sgpr folding in true16 (PR #128929)

[Shilei Tian via llvm-commits]

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@@ -1040,6 +1053,14 @@ void SIFoldOperandsImpl::foldOperand(
       }
     }
 
+    // Allow immediates COPYd into sgpr_lo16 to be further folded while
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shiltian wrote:

Is `COPYd` intentional?

https://github.com/llvm/llvm-project/pull/128929