[llvm] [MCP] Use MCRegUnit as the key type of CopyTracker::Copies map. NFC. (PR #98277)

[via llvm-commits]

llvmbot wrote:


<!--LLVM PR SUMMARY COMMENT-->

@llvm/pr-subscribers-llvm-regalloc

Author: Kai Luo (bzEq)

<details>
<summary>Changes</summary>

`CopyTracker` is indeed tracking at RegUnit level, not MCRegister.

---
Full diff: https://github.com/llvm/llvm-project/pull/98277.diff


1 Files Affected:

- (modified) llvm/lib/CodeGen/MachineCopyPropagation.cpp (+1-1) 


``````````diff
diff --git a/llvm/lib/CodeGen/MachineCopyPropagation.cpp b/llvm/lib/CodeGen/MachineCopyPropagation.cpp
index bdc17e99d1fb0..6adec4adf6c2d 100644
--- a/llvm/lib/CodeGen/MachineCopyPropagation.cpp
+++ b/llvm/lib/CodeGen/MachineCopyPropagation.cpp
@@ -112,7 +112,7 @@ class CopyTracker {
     bool Avail;
   };
 
-  DenseMap<MCRegister, CopyInfo> Copies;
+  DenseMap<MCRegUnit, CopyInfo> Copies;
 
 public:
   /// Mark all of the given registers and their subregisters as unavailable for

``````````

</details>


https://github.com/llvm/llvm-project/pull/98277