[llvm-branch-commits] [mlir] [MLIR][Mem2Reg] Change API to always retry promotion after changes (PR #91464)

[Tobias Gysi via llvm-branch-commits]

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@@ -636,20 +636,36 @@ LogicalResult mlir::tryToPromoteMemorySlots(
   // lazily and cached to avoid expensive recomputation.
   BlockIndexCache blockIndexCache;
 
-  for (PromotableAllocationOpInterface allocator : allocators) {
-    for (MemorySlot slot : allocator.getPromotableSlots()) {
-      if (slot.ptr.use_empty())
-        continue;
-
-      MemorySlotPromotionAnalyzer analyzer(slot, dominance, dataLayout);
-      std::optional<MemorySlotPromotionInfo> info = analyzer.computeInfo();
-      if (info) {
-        MemorySlotPromoter(slot, allocator, builder, dominance, dataLayout,
-                           std::move(*info), statistics, blockIndexCache)
-            .promoteSlot();
-        promotedAny = true;
+  SmallVector<PromotableAllocationOpInterface> workList(allocators.begin(),
+                                                        allocators.end());
+
+  SmallVector<PromotableAllocationOpInterface> newWorkList;
+  newWorkList.reserve(workList.size());
+  while (true) {
+    for (PromotableAllocationOpInterface allocator : workList) {
+      for (MemorySlot slot : allocator.getPromotableSlots()) {
+        if (slot.ptr.use_empty())
+          continue;
+
+        MemorySlotPromotionAnalyzer analyzer(slot, dominance, dataLayout);
+        std::optional<MemorySlotPromotionInfo> info = analyzer.computeInfo();
+        if (info) {
+          MemorySlotPromoter(slot, allocator, builder, dominance, dataLayout,
+                             std::move(*info), statistics, blockIndexCache)
+              .promoteSlot();
+          promotedAny = true;
+          continue;
+        }
+        newWorkList.push_back(allocator);
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gysit wrote:

I think we may add the same allocator multiple times here, if the allocator returns multiple slots?

https://github.com/llvm/llvm-project/pull/91464