[llvm] [NVPTX] don't erase CopyToRegs when folding movs into loads (PR #149393)

[Artem Belevich via llvm-commits]

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@@ -5060,11 +5060,9 @@ combineUnpackingMovIntoLoad(SDNode *N, TargetLowering::DAGCombinerInfo &DCI) {
           return !U.getUser()->use_empty();
         }
 
-        // Handle CopyToReg nodes that will become dead after our replacement
-        if (U.getUser()->getOpcode() == ISD::CopyToReg) {
-          DeadCopyToRegs.push_back(U.getUser());
+        // Peek through CopyToReg nodes
+        if (U.getUser()->getOpcode() == ISD::CopyToReg)
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Artem-B wrote:

I think we should add a TODO here, as returning `true` appears to leave the now unused register moves that pack the loaded value back. We do want to fix that.

https://github.com/llvm/llvm-project/pull/149393