Introduce a wrapper around ConversionPattern that operates on the derived class

Analogous to OpRewritePattern, this makes writing conversion patterns more convenient.

PiperOrigin-RevId: 275349854

mlir/include/mlir/Transforms/DialectConversion.h

@@ -223,6 +223,82 @@ private:
   using RewritePattern::rewrite;
 };
 
+/// OpConversionPattern is a wrapper around ConversionPattern that allows for
+/// matching and rewriting against an instance of a derived operation class as
+/// opposed to a raw Operation.
+template <typename SourceOp>
+struct OpConversionPattern : public ConversionPattern {
+  OpConversionPattern(MLIRContext *context, PatternBenefit benefit = 1)
+      : ConversionPattern(SourceOp::getOperationName(), benefit, context) {}
+
+  /// Wrappers around the ConversionPattern methods that pass the derived op
+  /// type.
+  void rewrite(Operation *op, ArrayRef<Value *> operands,
+               ConversionPatternRewriter &rewriter) const final {
+    rewrite(llvm::cast<SourceOp>(op), operands, rewriter);
+  }
+  void rewrite(Operation *op, ArrayRef<Value *> properOperands,
+               ArrayRef<Block *> destinations,
+               ArrayRef<ArrayRef<Value *>> operands,
+               ConversionPatternRewriter &rewriter) const final {
+    rewrite(llvm::cast<SourceOp>(op), properOperands, destinations, operands,
+            rewriter);
+  }
+  PatternMatchResult
+  matchAndRewrite(Operation *op, ArrayRef<Value *> properOperands,
+                  ArrayRef<Block *> destinations,
+                  ArrayRef<ArrayRef<Value *>> operands,
+                  ConversionPatternRewriter &rewriter) const final {
+    return matchAndRewrite(llvm::cast<SourceOp>(op), properOperands,
+                           destinations, operands, rewriter);
+  }
+  PatternMatchResult
+  matchAndRewrite(Operation *op, ArrayRef<Value *> operands,
+                  ConversionPatternRewriter &rewriter) const final {
+    return matchAndRewrite(llvm::cast<SourceOp>(op), operands, rewriter);
+  }
+
+  // TODO(b/142763075): Use OperandAdaptor when it supports access to unnamed
+  // operands.
+
+  /// Rewrite and Match methods that operate on the SourceOp type. These must be
+  /// overridden by the derived pattern class.
+  virtual void rewrite(SourceOp op, ArrayRef<Value *> operands,
+                       ConversionPatternRewriter &rewriter) const {
+    llvm_unreachable("must override matchAndRewrite or a rewrite method");
+  }
+
+  virtual void rewrite(SourceOp op, ArrayRef<Value *> properOperands,
+                       ArrayRef<Block *> destinations,
+                       ArrayRef<ArrayRef<Value *>> operands,
+                       ConversionPatternRewriter &rewriter) const {
+    llvm_unreachable("unimplemented rewrite for terminators");
+  }
+
+  virtual PatternMatchResult
+  matchAndRewrite(SourceOp op, ArrayRef<Value *> properOperands,
+                  ArrayRef<Block *> destinations,
+                  ArrayRef<ArrayRef<Value *>> operands,
+                  ConversionPatternRewriter &rewriter) const {
+    if (!match(op))
+      return matchFailure();
+    rewrite(op, properOperands, destinations, operands, rewriter);
+    return matchSuccess();
+  }
+
+  virtual PatternMatchResult
+  matchAndRewrite(SourceOp op, ArrayRef<Value *> operands,
+                  ConversionPatternRewriter &rewriter) const {
+    if (!match(op))
+      return matchFailure();
+    rewrite(op, operands, rewriter);
+    return matchSuccess();
+  }
+
+private:
+  using ConversionPattern::matchAndRewrite;
+};
+
 /// Add a pattern to the given pattern list to convert the signature of a FuncOp
 /// with the given type converter.
 void populateFuncOpTypeConversionPattern(OwningRewritePatternList &patterns,

mlir/lib/Transforms/DialectConversion.cpp

@@ -1393,16 +1393,14 @@ LogicalResult TypeConverter::convertSignatureArg(unsigned inputNo, Type type,
 /// Create a default conversion pattern that rewrites the type signature of a
 /// FuncOp.
 namespace {
-struct FuncOpSignatureConversion : public ConversionPattern {
+struct FuncOpSignatureConversion : public OpConversionPattern<FuncOp> {
   FuncOpSignatureConversion(MLIRContext *ctx, TypeConverter &converter)
-      : ConversionPattern(FuncOp::getOperationName(), 1, ctx),
-        converter(converter) {}
+      : OpConversionPattern(ctx), converter(converter) {}
 
   /// Hook for derived classes to implement combined matching and rewriting.
   PatternMatchResult
-  matchAndRewrite(Operation *op, ArrayRef<Value *> operands,
+  matchAndRewrite(FuncOp funcOp, ArrayRef<Value *> operands,
                   ConversionPatternRewriter &rewriter) const override {
-    auto funcOp = cast<FuncOp>(op);
     FunctionType type = funcOp.getType();
 
     // Convert the original function arguments.
@@ -1425,7 +1423,7 @@ struct FuncOpSignatureConversion : public ConversionPattern {
 
     // Tell the rewriter to convert the region signature.
     rewriter.applySignatureConversion(&newFuncOp.getBody(), result);
-    rewriter.eraseOp(op);
+    rewriter.eraseOp(funcOp);
     return matchSuccess();
   }