[mlir] Add LogOp lowering from Complex dialect to Standard/Math dialect.

mlir/lib/Conversion/ComplexToStandard/ComplexToStandard.cpp

matchAndRewrite(complex::ExpOp op, ArrayRef<Value> operands,
     Value resultImag = rewriter.create<MulFOp>(loc, expReal, sinImag);
 
     rewriter.replaceOpWithNewOp<complex::CreateOp>(op, type, resultReal,
                                                    resultImag);
     return success();
   }
 };
 
+struct LogOpConversion : public OpConversionPattern<complex::LogOp> {
+  using OpConversionPattern<complex::LogOp>::OpConversionPattern;
+
+  LogicalResult
+  matchAndRewrite(complex::LogOp op, ArrayRef<Value> operands,
+                  ConversionPatternRewriter &rewriter) const override {
+    complex::LogOp::Adaptor transformed(operands);
+    auto type = transformed.complex().getType().cast<ComplexType>();
+    auto elementType = type.getElementType().cast<FloatType>();
+    mlir::ImplicitLocOpBuilder b(op.getLoc(), rewriter);
+
+    Value abs = b.create<complex::AbsOp>(elementType, transformed.complex());
+    Value resultReal = b.create<math::LogOp>(elementType, abs);
+    Value real = b.create<complex::ReOp>(elementType, transformed.complex());
+    Value imag = b.create<complex::ImOp>(elementType, transformed.complex());
+    Value resultImag = b.create<math::Atan2Op>(elementType, imag, real);
+    rewriter.replaceOpWithNewOp<complex::CreateOp>(op, type, resultReal,
+                                                   resultImag);
+    return success();
+  }
+};
+
 struct NegOpConversion : public OpConversionPattern<complex::NegOp> {
   using OpConversionPattern<complex::NegOp>::OpConversionPattern;
 
   LogicalResult
   matchAndRewrite(complex::NegOp op, ArrayRef<Value> operands,
                   ConversionPatternRewriter &rewriter) const override {
     complex::NegOp::Adaptor transformed(operands);
     auto loc = op.getLoc();
void mlir::populateComplexToStandardConversionPatterns(
     RewritePatternSet &patterns) {
   // clang-format off
   patterns.add<
       AbsOpConversion,
       ComparisonOpConversion<complex::EqualOp, CmpFPredicate::OEQ>,
       ComparisonOpConversion<complex::NotEqualOp, CmpFPredicate::UNE>,
       DivOpConversion,
       ExpOpConversion,
+      LogOpConversion,
       NegOpConversion,
       SignOpConversion>(patterns.getContext());
   // clang-format on
 }
 
 namespace {
 struct ConvertComplexToStandardPass
     : public ConvertComplexToStandardBase<ConvertComplexToStandardPass> {
   void runOnFunction() override;
 };
 
 void ConvertComplexToStandardPass::runOnFunction() {
   auto function = getFunction();
 
   // Convert to the Standard dialect using the converter defined above.
   RewritePatternSet patterns(&getContext());
   populateComplexToStandardConversionPatterns(patterns);
 
   ConversionTarget target(getContext());
   target.addLegalDialect<StandardOpsDialect, math::MathDialect,
                          complex::ComplexDialect>();
   target.addIllegalOp<complex::AbsOp, complex::DivOp, complex::EqualOp,
-                      complex::ExpOp, complex::NotEqualOp, complex::NegOp,
-                      complex::SignOp>();
+                      complex::ExpOp, complex::LogOp, complex::NotEqualOp,
+                      complex::NegOp, complex::SignOp>();
   if (failed(applyPartialConversion(function, target, std::move(patterns))))
     signalPassFailure();
 }
 } // namespace
 
 std::unique_ptr<OperationPass<FuncOp>>
 mlir::createConvertComplexToStandardPass() {
   return std::make_unique<ConvertComplexToStandardPass>();
 }

mlir/test/Conversion/ComplexToStandard/convert-to-standard.mlir

 // CHECK-DAG: %[[COS_IMAG:.*]] = math.cos %[[IMAG]] : f32
 // CHECK-DAG: %[[EXP_REAL:.*]] = math.exp %[[REAL]] : f32
 // CHECK-DAG: %[[RESULT_REAL:.]] = mulf %[[EXP_REAL]], %[[COS_IMAG]] : f32
 // CHECK-DAG: %[[SIN_IMAG:.*]] = math.sin %[[IMAG]] : f32
 // CHECK-DAG: %[[RESULT_IMAG:.*]] = mulf %[[EXP_REAL]], %[[SIN_IMAG]] : f32
 // CHECK: %[[RESULT:.*]] = complex.create %[[RESULT_REAL]], %[[RESULT_IMAG]] : complex<f32>
 // CHECK: return %[[RESULT]] : complex<f32>
 
+// CHECK-LABEL: func @complex_log
+// CHECK-SAME: %[[ARG:.*]]: complex<f32>
+func @complex_log(%arg: complex<f32>) -> complex<f32> {
+  %log = complex.log %arg: complex<f32>
+  return %log : complex<f32>
+}
+// CHECK: %[[REAL:.*]] = complex.re %[[ARG]] : complex<f32>
+// CHECK: %[[IMAG:.*]] = complex.im %[[ARG]] : complex<f32>
+// CHECK: %[[SQR_REAL:.*]] = mulf %[[REAL]], %[[REAL]] : f32
+// CHECK: %[[SQR_IMAG:.*]] = mulf %[[IMAG]], %[[IMAG]] : f32
+// CHECK: %[[SQ_NORM:.*]] = addf %[[SQR_REAL]], %[[SQR_IMAG]] : f32
+// CHECK: %[[NORM:.*]] = math.sqrt %[[SQ_NORM]] : f32
+// CHECK: %[[RESULT_REAL:.*]] = math.log %[[NORM]] : f32
+// CHECK: %[[REAL2:.*]] = complex.re %[[ARG]] : complex<f32>
+// CHECK: %[[IMAG2:.*]] = complex.im %[[ARG]] : complex<f32>
+// CHECK: %[[RESULT_IMAG:.*]] = math.atan2 %[[IMAG2]], %[[REAL2]] : f32
+// CHECK: %[[RESULT:.*]] = complex.create %[[RESULT_REAL]], %[[RESULT_IMAG]] : complex<f32>
+// CHECK: return %[[RESULT]] : complex<f32>
+
 // CHECK-LABEL: func @complex_neg
 // CHECK-SAME: %[[ARG:.*]]: complex<f32>
 func @complex_neg(%arg: complex<f32>) -> complex<f32> {
   %neg = complex.neg %arg: complex<f32>
   return %neg : complex<f32>
 }
 // CHECK: %[[REAL:.*]] = complex.re %[[ARG]] : complex<f32>
 // CHECK: %[[IMAG:.*]] = complex.im %[[ARG]] : complex<f32>