[ExtractInstances] Fix nondeterminism with MapVector. (#4749)

This fixes nondeterminism caused by iteration over DenseMap. Instead use MapVector to guarantee determinism.
llvm · Mar 2, 2023 · ec49cbe · ec49cbe
1 parent f340cda
commit ec49cbe
Showing 1 changed file with 1 addition and 1 deletion.
diff --git a/lib/Dialect/FIRRTL/Transforms/ExtractInstances.cpp b/lib/Dialect/FIRRTL/Transforms/ExtractInstances.cpp
@@ -845,7 +845,7 @@ void ExtractInstancesPass::groupInstances() {
   // module. Note that we cannot group instances that landed in different parent
   // modules into the same submodule, so we use that parent module as a grouping
   // key.
-  SmallDenseMap<std::pair<Operation *, StringRef>, SmallVector<InstanceOp>>
+  llvm::MapVector<std::pair<Operation *, StringRef>, SmallVector<InstanceOp>>
       instsByWrapper;
   for (auto &[inst, info] : extractedInstances) {
     if (!info.wrapperModule.empty())