Improve SimplifyLocals compile-time performance

Author: Changqing-JING

src/ir/effects.h

@@ -140,8 +140,8 @@ class EffectAnalyzer {
   const Module& module;
   FeatureSet features;
 
-  std::set<Index> localsRead;
-  std::set<Index> localsWritten;
+  std::unordered_set<Index> localsRead;
+  std::unordered_set<Index> localsWritten;
   std::unordered_set<Name> mutableGlobalsRead;
   std::unordered_set<Name> globalsWritten;
 
@@ -296,6 +296,20 @@ class EffectAnalyzer {
     return hasSideEffects() || accessesLocal() || readsMutableGlobalState();
   }
 
+  // Check if this has any ordering-relevant effects beyond local variable
+  // access. This is used by SimplifyLocals' reverse-index optimization to
+  // classify sinkables: those with only local effects can be looked up via
+  // the local reverse index, while those with non-local effects need broader
+  // conflict checks.
+  //
+  // This is derived from the same helpers used by orderedBefore(), so it
+  // automatically stays in sync when new effect types are added.
+  bool hasNonLocalOrderingEffects() const {
+    return transfersControlFlow() || writesGlobalState() ||
+           readsMutableGlobalState() || danglingPop || trap ||
+           hasSynchronization() || mayNotReturn;
+  }
+
   // check if we break to anything external from ourselves
   bool hasExternalBreakTargets() const { return !breakTargets.empty(); }