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

[Benjamin Maxwell via llvm-commits]

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@@ -21,9 +20,58 @@ using namespace llvm;
 
 namespace {
 
+static bool expandFormTransposedRegTuple(MachineBasicBlock &MBB,
+                                         MachineInstr &MI, LiveIntervals &LIS) {
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MacDue wrote:

Yes, this pass runs immediately after the pre-RA scheduler, but before greedy. 

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