Lower memref.reinterpret_cast to EmitC

mlir/lib/Conversion/MemRefToEmitC/MemRefToEmitC.cpp

@@ -230,6 +230,33 @@ struct ConvertExpandShape final
   }
 };
 
+struct ConvertReinterpretCast final
+    : public OpConversionPattern<memref::ReinterpretCastOp> {
+  using OpConversionPattern::OpConversionPattern;
+
+  LogicalResult
+  matchAndRewrite(memref::ReinterpretCastOp op, OpAdaptor operands,
+                  ConversionPatternRewriter &rewriter) const override {
+    auto arrayValue =
+        dyn_cast<TypedValue<emitc::ArrayType>>(operands.getSource());
+    if (!arrayValue) {
+      return rewriter.notifyMatchFailure(op.getLoc(), "expected array type");
+    }
+
+    auto resultTy = getTypeConverter()->convertType(op.getType());
+    if (!resultTy) {
+      return rewriter.notifyMatchFailure(op.getLoc(),
+                                         "cannot convert result type");
+    }
+
+    auto newCastOp = rewriter.create<emitc::CastOp>(op->getLoc(), resultTy,
+                                                    operands.getSource());
+    newCastOp.setReference(true);
+    rewriter.replaceOp(op, newCastOp);
+    return success();
+  }
+};
+
 } // namespace
 
 void mlir::populateMemRefToEmitCTypeConversion(TypeConverter &typeConverter) {
@@ -251,6 +278,6 @@ void mlir::populateMemRefToEmitCTypeConversion(TypeConverter &typeConverter) {
 void mlir::populateMemRefToEmitCConversionPatterns(RewritePatternSet &patterns,
                                                    TypeConverter &converter) {
   patterns.add<ConvertAlloca, ConvertGlobal, ConvertGetGlobal, ConvertLoad,
-               ConvertStore, ConvertCollapseShape, ConvertExpandShape>(
-      converter, patterns.getContext());
+               ConvertStore, ConvertCollapseShape, ConvertExpandShape,
+               ConvertReinterpretCast>(converter, patterns.getContext());
 }

mlir/test/Conversion/MemRefToEmitC/memref-to-emitc-failed.mlir

@@ -61,3 +61,48 @@ func.func @memref_collapse_dyn_shape(%arg: memref<?x5xi32>) -> memref<?xi32> {
   %0 = memref.collapse_shape %arg [[0, 1]] : memref<?x5xi32> into memref<?xi32>
   return %0 : memref<?xi32>
 }
+
+// -----
+
+// CHECK-LABEL: memref_reinterpret_cast_dyn_shape
+func.func @memref_reinterpret_cast_dyn_shape(%arg: memref<2x5xi32>, %size: index) -> memref<?xi32> {
+  // expected-error@+1 {{failed to legalize operation 'memref.reinterpret_cast'}}
+  %0 = memref.reinterpret_cast %arg to offset: [0], sizes: [%size], strides: [1] : memref<2x5xi32> to memref<?xi32>
+  return %0 : memref<?xi32>
+}
+
+// -----
+
+// CHECK-LABEL: memref_reinterpret_cast_dyn_offset
+func.func @memref_reinterpret_cast_dyn_offset(%arg: memref<2x5xi32>, %offset: index) -> memref<10xi32, strided<[1], offset: ?>> {
+  // expected-error@+1 {{failed to legalize operation 'memref.reinterpret_cast'}}
+  %0 = memref.reinterpret_cast %arg to offset: [%offset], sizes: [10], strides: [1] : memref<2x5xi32> to memref<10xi32, strided<[1], offset: ?>>
+  return %0 : memref<10xi32, strided<[1], offset:? >>
+}
+
+// -----
+
+// CHECK-LABEL: memref_reinterpret_cast_static_offset
+func.func @memref_reinterpret_cast_static_offset(%arg: memref<2x5xi32>) -> memref<10xi32, strided<[1], offset: 10>> {
+  // expected-error@+1 {{failed to legalize operation 'memref.reinterpret_cast'}}
+  %0 = memref.reinterpret_cast %arg to offset: [10], sizes: [10], strides: [1] : memref<2x5xi32> to memref<10xi32, strided<[1], offset: 10>>
+  return %0 : memref<10xi32, strided<[1], offset: 10>>
+}
+
+// -----
+
+// CHECK-LABEL: memref_reinterpret_cast_static_strides
+func.func @memref_reinterpret_cast_offset(%arg: memref<2x5xi32>) -> memref<10xi32, strided<[2], offset: 0>> {
+  // expected-error@+1 {{failed to legalize operation 'memref.reinterpret_cast'}}
+  %0 = memref.reinterpret_cast %arg to offset: [0], sizes: [10], strides: [2] : memref<2x5xi32> to memref<10xi32, strided<[2], offset: 0>>
+  return %0 : memref<10xi32, strided<[2], offset: 0>>
+}
+
+// -----
+
+// CHECK-LABEL: memref_reinterpret_cast_dyn_strides
+func.func @memref_reinterpret_cast_offset(%arg: memref<2x5xi32>, %stride: index) -> memref<10xi32, strided<[?], offset: 0>> {
+  // expected-error@+1 {{failed to legalize operation 'memref.reinterpret_cast'}}
+  %0 = memref.reinterpret_cast %arg to offset: [0], sizes: [10], strides: [%stride] : memref<2x5xi32> to memref<10xi32, strided<[?], offset: 0>>
+  return %0 : memref<10xi32, strided<[?], offset: 0>>
+}

mlir/test/Conversion/MemRefToEmitC/memref-to-emitc.mlir

@@ -94,3 +94,12 @@ func.func @memref_collapse_shape(%arg: memref<2x5xi32>) -> memref<10xi32> {
   %0 = memref.collapse_shape %arg [[0, 1]] : memref<2x5xi32> into memref<10xi32>
   return %0 : memref<10xi32>
 }
+
+// -----
+
+// CHECK-LABEL: memref_reinterpret_cast
+func.func @memref_reinterpret_cast(%arg: memref<2x5xi32>) -> memref<10xi32> {
+  // CHECK: emitc.cast %{{[^ ]*}} : !emitc.array<2x5xi32> to !emitc.array<10xi32> ref
+  %0 = memref.reinterpret_cast %arg to offset: [0], sizes: [10], strides: [1] : memref<2x5xi32> to memref<10xi32>
+  return %0 : memref<10xi32>
+}