[mlir][emitc] arith.negf to EmitC conversion (llvm#95372)

Lower arith.negf to the unary minus in EmitC.

Author: TinaAMD

mlir/lib/Conversion/ArithToEmitC/ArithToEmitC.cpp

@@ -288,6 +288,34 @@ class CmpIOpConversion : public OpConversionPattern<arith::CmpIOp> {
   }
 };
 
+class NegFOpConversion : public OpConversionPattern<arith::NegFOp> {
+public:
+  using OpConversionPattern::OpConversionPattern;
+
+  LogicalResult
+  matchAndRewrite(arith::NegFOp op, OpAdaptor adaptor,
+                  ConversionPatternRewriter &rewriter) const override {
+
+    auto adaptedOp = adaptor.getOperand();
+    auto adaptedOpType = adaptedOp.getType();
+
+    if (isa<TensorType>(adaptedOpType) || isa<VectorType>(adaptedOpType)) {
+      return rewriter.notifyMatchFailure(
+          op.getLoc(),
+          "negf currently only supports scalar types, not vectors or tensors");
+    }
+
+    if (!emitc::isSupportedFloatType(adaptedOpType)) {
+      return rewriter.notifyMatchFailure(
+          op.getLoc(), "floating-point type is not supported by EmitC");
+    }
+
+    rewriter.replaceOpWithNewOp<emitc::UnaryMinusOp>(op, adaptedOpType,
+                                                     adaptedOp);
+    return success();
+  }
+};
+
 template <typename ArithOp, bool castToUnsigned>
 class CastConversion : public OpConversionPattern<ArithOp> {
 public:
@@ -621,6 +649,7 @@ void mlir::populateArithToEmitCPatterns(TypeConverter &typeConverter,
     BitwiseOpConversion<arith::XOrIOp, emitc::BitwiseXorOp>,
     CmpFOpConversion,
     CmpIOpConversion,
+    NegFOpConversion,
     SelectOpConversion,
     // Truncation is guaranteed for unsigned types.
     UnsignedCastConversion<arith::TruncIOp>,

mlir/test/Conversion/ArithToEmitC/arith-to-emitc-unsupported.mlir

@@ -81,6 +81,30 @@ func.func @arith_cmpf_tensor(%arg0: tensor<5xf32>, %arg1: tensor<5xf32>) -> tens
 
 // -----
 
+func.func @arith_negf_f80(%arg0: f80) -> f80 {
+  // expected-error @+1 {{failed to legalize operation 'arith.negf'}}
+  %n = arith.negf %arg0 : f80
+  return %n: f80
+}
+
+// -----
+
+func.func @arith_negf_tensor(%arg0: tensor<5xf32>) -> tensor<5xf32> {
+  // expected-error @+1 {{failed to legalize operation 'arith.negf'}}
+  %n = arith.negf %arg0 : tensor<5xf32>
+  return %n: tensor<5xf32>
+}
+
+// -----
+
+func.func @arith_negf_vector(%arg0: vector<5xf32>) -> vector<5xf32> {
+  // expected-error @+1 {{failed to legalize operation 'arith.negf'}}
+  %n = arith.negf %arg0 : vector<5xf32>
+  return %n: vector<5xf32>
+}
+
+// -----
+
 func.func @arith_extsi_i1_to_i32(%arg0: i1) {
   // expected-error @+1 {{failed to legalize operation 'arith.extsi'}}
   %idx = arith.extsi %arg0 : i1 to i32

mlir/test/Conversion/ArithToEmitC/arith-to-emitc.mlir

@@ -422,6 +422,17 @@ func.func @arith_cmpi_predicates(%arg0: i32, %arg1: i32) {
 
 // -----
 
+func.func @arith_negf(%arg0: f32) -> f32 {
+  // CHECK-LABEL: arith_negf
+  // CHECK-SAME: %[[Arg0:[^ ]*]]: f32
+  // CHECK: %[[N:[^ ]*]] = emitc.unary_minus %[[Arg0]] : (f32) -> f32
+  %n = arith.negf %arg0 : f32
+  // CHECK: return %[[N]]
+  return %n: f32
+}
+
+// -----
+
 func.func @arith_float_to_int_cast_ops(%arg0: f32, %arg1: f64) {
   // CHECK: emitc.cast %arg0 : f32 to i32
   %0 = arith.fptosi %arg0 : f32 to i32