[llvm] [AArch64] Expand FORM_TRANSPOSED_REG_TUPLE to copies before regalloc (PR #207205)

[Sander de Smalen via llvm-commits]

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@@ -21,9 +20,70 @@ using namespace llvm;
 
 namespace {
 
+/// Expands FORM_TRANSPOSED_REG_TUPLE_{X2|X4}_PSEUDO instructions into a
+/// copy sequences. Note: This expansion occurs immediately before greedy
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sdesmalen-arm wrote:

nit:
```suggestion
/// copy sequence. Note: This expansion occurs immediately before greedy
```

https://github.com/llvm/llvm-project/pull/207205