Add LogOp to Complex dialect.

[akuegel]

Summary

Add an op to compute the natural logarithm of a complex number.
Also add some missing tests for recently added ops.

[akuegel]

Replace tensor with value.

mlir/include/mlir/Dialect/Complex/IR/ComplexOps.td

 //===----------------------------------------------------------------------===//
 // ExpOp
 //===----------------------------------------------------------------------===//
 
 def ExpOp : ComplexUnaryOp<"exp", [SameOperandsAndResultType]> {
   let summary = "computes exponential of a complex number";
   let description = [{
     The `exp` op takes a single complex number and computes the exponential of
-    it, i.e. `exp(x)` or `e^(x)`, where `x` is the input tensor.
+    it, i.e. `exp(x)` or `e^(x)`, where `x` is the input value.
     `e` denotes Euler's number and is approximately equal to 2.718281.
 
     Example:
 
     ```mlir
     %a = complex.exp %b : complex<f32>
     ```
   }];
let description = [{
     ```
   }];
 
   let results = (outs AnyFloat:$imaginary);
   let hasFolder = 1;
 }
 
 //===----------------------------------------------------------------------===//
+// LogOp
+//===----------------------------------------------------------------------===//
+
+def LogOp : ComplexUnaryOp<"log", [SameOperandsAndResultType]> {
+  let summary = "computes natural logarithm of a complex number";
+  let description = [{
+    The `log` op takes a single complex number and computes the natural
+    logarithm of it, i.e. `log(x)` or `log_e(x)`, where `x` is the input value.
+    `e` denotes Euler's number and is approximately equal to 2.718281.
+
+    Example:
+
+    ```mlir
+    %a = complex.log %b : complex<f32>
+    ```
+  }];
+
+  let results = (outs Complex<AnyFloat>:$result);
+}
+
+//===----------------------------------------------------------------------===//
 // MulOp
 //===----------------------------------------------------------------------===//
 
 def MulOp : ComplexArithmeticOp<"mul"> {
   let summary = "complex multiplication";
   let description = [{
     The `mul` operation takes two complex numbers and returns their product:
 

mlir/test/Dialect/Complex/ops.mlir

func @ops(%f: f32) {
   %sum = complex.add %complex, %complex : complex<f32>
 
   // CHECK: complex.div %[[C]], %[[C]] : complex<f32>
   %div = complex.div %complex, %complex : complex<f32>
 
   // CHECK: complex.eq %[[C]], %[[C]] : complex<f32>
   %eq = complex.eq %complex, %complex : complex<f32>
 
-  // CHECK: complex.neq %[[C]], %[[C]] : complex<f32>
-  %neq = complex.neq %complex, %complex : complex<f32>
+  // CHECK: complex.exp %[[C]] : complex<f32>
+  %exp = complex.exp %complex : complex<f32>
+
+  // CHECK: complex.log %[[C]] : complex<f32>
+  %log = complex.log %complex : complex<f32>
 
   // CHECK: complex.mul %[[C]], %[[C]] : complex<f32>
   %prod = complex.mul %complex, %complex : complex<f32>
 
+  // CHECK: complex.neg %[[C]] : complex<f32>
+  %neg = complex.neg %complex : complex<f32>
+
+  // CHECK: complex.neq %[[C]], %[[C]] : complex<f32>
+  %neq = complex.neq %complex, %complex : complex<f32>
+
+  // CHECK: complex.sign %[[C]] : complex<f32>
+  %sign = complex.sign %complex : complex<f32>
+
   // CHECK: complex.sub %[[C]], %[[C]] : complex<f32>
   %diff = complex.sub %complex, %complex : complex<f32>
   return
 }