[llvm] [MachineCopyPropagation][NFC] Refactor EliminateSpillageCopies (PR #192609)

[Matt Arsenault via llvm-commits]

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@@ -1367,44 +1380,44 @@ void MachineCopyPropagation::eliminateSpillageCopies(MachineBasicBlock &MBB) {
         }
       };
 
-  auto IsFoldableCopy = [this](const MachineInstr &MaybeCopy) {
+  auto GetFoldableCopy =
+      [this](const MachineInstr &MaybeCopy) -> std::optional<DestSourcePair> {
     if (MaybeCopy.getNumImplicitOperands() > 0)
-      return false;
+      return std::nullopt;
     std::optional<DestSourcePair> CopyOperands =
         isCopyInstr(MaybeCopy, *TII, UseCopyInstr);
     if (!CopyOperands)
-      return false;
+      return std::nullopt;
     auto [Dst, Src] = getDstSrcMCRegs(*CopyOperands);
-    return Src && Dst && !TRI->regsOverlap(Src, Dst) &&
-           CopyOperands->Source->isRenamable() &&
-           CopyOperands->Destination->isRenamable();
+    if (Src && Dst && !TRI->regsOverlap(Src, Dst) &&
+        CopyOperands->Source->isRenamable() &&
+        CopyOperands->Destination->isRenamable())
+      return CopyOperands;
+
+    return std::nullopt;
   };
 
-  auto IsSpillReloadPair = [&, this](const MachineInstr &Spill,
-                                     const MachineInstr &Reload) {
-    if (!IsFoldableCopy(Spill) || !IsFoldableCopy(Reload))
-      return false;
-    std::optional<DestSourcePair> SpillCopy =
-        isCopyInstr(Spill, *TII, UseCopyInstr);
-    std::optional<DestSourcePair> ReloadCopy =
-        isCopyInstr(Reload, *TII, UseCopyInstr);
-    if (!SpillCopy || !ReloadCopy)
+  auto IsSpillReloadPair = [&](const MachineInstr &Spill,
+                               const MachineInstr &Reload) {
+    std::optional<DestSourcePair> FoldableSpillCopy = GetFoldableCopy(Spill);
+    std::optional<DestSourcePair> FoldableReloadCopy = GetFoldableCopy(Reload);
+    if (!FoldableReloadCopy || !FoldableSpillCopy)
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arsenm wrote:

Early exit after first one fails 

https://github.com/llvm/llvm-project/pull/192609