[llvm] [TII] Split isTrivialReMaterializable into two versions [nfc] (PR #160377)

[Philip Reames via llvm-commits]

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@@ -1777,9 +1777,9 @@ bool PreRARematStage::canIncreaseOccupancyOrReduceSpill() {
   for (unsigned I = 0, E = DAG.Regions.size(); I != E; ++I) {
     auto Region = DAG.Regions[I];
     for (auto MI = Region.first; MI != Region.second; ++MI) {
-      // The instruction must be trivially rematerializable.
+      // The instruction must be rematerializable.
       MachineInstr &DefMI = *MI;
-      if (!isTriviallyReMaterializable(DefMI))
+      if (!isReMaterializable(DefMI))
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preames wrote:

@arsenm I want to draw your attention to this change.  I'm suspecting the use of non-trivial remat might be a latent bug here from the comments, and code structure.  When I tried to make this actually trivial, I do see test failures though.  

https://github.com/llvm/llvm-project/pull/160377