diff --git a/mlir/include/mlir/Rewrite/FrozenRewritePatternList.h b/mlir/include/mlir/Rewrite/FrozenRewritePatternList.h
--- a/mlir/include/mlir/Rewrite/FrozenRewritePatternList.h
+++ b/mlir/include/mlir/Rewrite/FrozenRewritePatternList.h
@@ -18,34 +18,52 @@
 
 /// This class represents a frozen set of patterns that can be processed by a
 /// pattern applicator. This class is designed to enable caching pattern lists
-/// such that they need not be continuously recomputed.
+/// such that they need not be continuously recomputed. Note that all copies of
+/// this class share the same compiled pattern list, allowing for a reduction in
+/// the number of duplicated patterns that need to be created.
 class FrozenRewritePatternList {
   using NativePatternListT = std::vector<std::unique_ptr<RewritePattern>>;
 
 public:
   /// Freeze the patterns held in `patterns`, and take ownership.
+  FrozenRewritePatternList();
   FrozenRewritePatternList(OwningRewritePatternList &&patterns);
-  FrozenRewritePatternList(FrozenRewritePatternList &&patterns);
+  FrozenRewritePatternList(FrozenRewritePatternList &&patterns) = default;
+  FrozenRewritePatternList(const FrozenRewritePatternList &patterns) = default;
+  FrozenRewritePatternList &
+  operator=(const FrozenRewritePatternList &patterns) = default;
+  FrozenRewritePatternList &
+  operator=(FrozenRewritePatternList &&patterns) = default;
   ~FrozenRewritePatternList();
 
   /// Return the native patterns held by this list.
   iterator_range<llvm::pointee_iterator<NativePatternListT::const_iterator>>
   getNativePatterns() const {
+    const NativePatternListT &nativePatterns = impl->nativePatterns;
     return llvm::make_pointee_range(nativePatterns);
   }
 
   /// Return the compiled PDL bytecode held by this list. Returns null if
   /// there are no PDL patterns within the list.
   const detail::PDLByteCode *getPDLByteCode() const {
-    return pdlByteCode.get();
+    return impl->pdlByteCode.get();
   }
 
 private:
-  /// The set of.
-  std::vector<std::unique_ptr<RewritePattern>> nativePatterns;
+  /// The internal implementation of the frozen pattern list.
+  struct Impl {
+    /// The set of native C++ rewrite patterns.
+    NativePatternListT nativePatterns;
 
-  /// The bytecode containing the compiled PDL patterns.
-  std::unique_ptr<detail::PDLByteCode> pdlByteCode;
+    /// The bytecode containing the compiled PDL patterns.
+    std::unique_ptr<detail::PDLByteCode> pdlByteCode;
+  };
+
+  /// A pointer to the internal pattern list. This uses a shared_ptr to avoid
+  /// the need to compile the same pattern list multiple times. For example,
+  /// during multi-threaded pass execution, all copies of a pass can share the
+  /// same pattern list.
+  std::shared_ptr<Impl> impl;
 };
 
 } // end namespace mlir
diff --git a/mlir/lib/Rewrite/FrozenRewritePatternList.cpp b/mlir/lib/Rewrite/FrozenRewritePatternList.cpp
--- a/mlir/lib/Rewrite/FrozenRewritePatternList.cpp
+++ b/mlir/lib/Rewrite/FrozenRewritePatternList.cpp
@@ -50,12 +50,16 @@
 // FrozenRewritePatternList
 //===----------------------------------------------------------------------===//
 
+FrozenRewritePatternList::FrozenRewritePatternList()
+    : impl(std::make_shared<Impl>()) {}
+
 FrozenRewritePatternList::FrozenRewritePatternList(
     OwningRewritePatternList &&patterns)
-    : nativePatterns(std::move(patterns.getNativePatterns())) {
-  PDLPatternModule &pdlPatterns = patterns.getPDLPatterns();
+    : impl(std::make_shared<Impl>()) {
+  impl->nativePatterns = std::move(patterns.getNativePatterns());
 
   // Generate the bytecode for the PDL patterns if any were provided.
+  PDLPatternModule &pdlPatterns = patterns.getPDLPatterns();
   ModuleOp pdlModule = pdlPatterns.getModule();
   if (!pdlModule)
     return;
@@ -64,14 +68,9 @@
         "failed to lower PDL pattern module to the PDL Interpreter");
 
   // Generate the pdl bytecode.
-  pdlByteCode = std::make_unique<detail::PDLByteCode>(
+  impl->pdlByteCode = std::make_unique<detail::PDLByteCode>(
       pdlModule, pdlPatterns.takeConstraintFunctions(),
       pdlPatterns.takeCreateFunctions(), pdlPatterns.takeRewriteFunctions());
 }
 
-FrozenRewritePatternList::FrozenRewritePatternList(
-    FrozenRewritePatternList &&patterns)
-    : nativePatterns(std::move(patterns.nativePatterns)),
-      pdlByteCode(std::move(patterns.pdlByteCode)) {}
-
 FrozenRewritePatternList::~FrozenRewritePatternList() {}