Add template function and a few tests

Author: Sh0g0-1758

libc/src/__support/complex_type.h

@@ -16,5 +16,13 @@ template <typename T> struct Complex {
   T real;
   T imag;
 };
+
+template <typename T, typename U>
+T conjugate(T c) {
+  Complex<U> c_c = cpp::bit_cast<Complex<U>>(c);
+  c_c.imag = -c_c.imag;
+  return cpp::bit_cast<T>(c_c);
+}
+
 } // namespace LIBC_NAMESPACE_DECL
 #endif // LLVM_LIBC_SRC___SUPPORT_COMPLEX_TYPE_H

libc/src/complex/generic/conj.cpp

@@ -14,8 +14,7 @@
 namespace LIBC_NAMESPACE_DECL {
 
 LLVM_LIBC_FUNCTION(_Complex double, conj, (_Complex double x)) {
-  Complex<double> x_c = cpp::bit_cast<Complex<double>>(x);
-  return (x_c.real - x_c.imag * 1.0i);
+  return conjugate<_Complex double, double>(x);
 }
 
 } // namespace LIBC_NAMESPACE_DECL

libc/src/complex/generic/conjf.cpp

@@ -14,8 +14,7 @@
 namespace LIBC_NAMESPACE_DECL {
 
 LLVM_LIBC_FUNCTION(_Complex float, conjf, (_Complex float x)) {
-  Complex<float> x_c = cpp::bit_cast<Complex<float>>(x);
-  return (x_c.real - x_c.imag * (_Complex float)1.0i);
+  return conjugate<_Complex float, float>(x);
 }
 
 } // namespace LIBC_NAMESPACE_DECL

libc/src/complex/generic/conjf128.cpp

@@ -16,8 +16,7 @@
 namespace LIBC_NAMESPACE_DECL {
 
 LLVM_LIBC_FUNCTION(cfloat128, conjf128, (cfloat128 x)) {
-  Complex<float128> x_c = cpp::bit_cast<Complex<float128>>(x);
-  return (x_c.real - x_c.imag * (cfloat128)1.0i);
+  return conjugate<cfloat128, float128>(x);
 }
 
 } // namespace LIBC_NAMESPACE_DECL

libc/src/complex/generic/conjf16.cpp

@@ -16,8 +16,7 @@
 namespace LIBC_NAMESPACE_DECL {
 
 LLVM_LIBC_FUNCTION(cfloat16, conjf16, (cfloat16 x)) {
-  Complex<float16> x_c = cpp::bit_cast<Complex<float16>>(x);
-  return (x_c.real - x_c.imag * (cfloat16)1.0i);
+  return conjugate<cfloat16, float16>(x);
 }
 
 } // namespace LIBC_NAMESPACE_DECL

libc/src/complex/generic/conjl.cpp

@@ -14,8 +14,7 @@
 namespace LIBC_NAMESPACE_DECL {
 
 LLVM_LIBC_FUNCTION(_Complex long double, conjl, (_Complex long double x)) {
-  Complex<long double> x_c = cpp::bit_cast<Complex<long double>>(x);
-  return (x_c.real - x_c.imag * (_Complex long double)1.0i);
+  return conjugate<_Complex long double, long double>(x);
 }
 
 } // namespace LIBC_NAMESPACE_DECL

libc/test/src/complex/CImagTest.h

@@ -42,6 +42,10 @@ class CImagTest : public LIBC_NAMESPACE::testing::FEnvSafeTest {
     EXPECT_FP_EQ(func(CFPT(-0.0 + 0.0i)), 0.0);
     EXPECT_FP_EQ(func(CFPT(0.0 - 0.0i)), -0.0);
     EXPECT_FP_EQ(func(CFPT(-0.0 - 0.0i)), -0.0);
+    EXPECT_FP_EQ(func(CFPT(0.0)), 0.0);
+    EXPECT_FP_EQ(func(CFPT(-0.0)), 0.0);
+    EXPECT_FP_EQ(func(CFPT(0.0i)), 0.0);
+    EXPECT_FP_EQ(func(CFPT(-0.0i)), -0.0);
   }
 
   void testRoundedNumbers(CImagFunc func) {

libc/test/src/complex/CRealTest.h

@@ -41,6 +41,10 @@ class CRealTest : public LIBC_NAMESPACE::testing::FEnvSafeTest {
     EXPECT_FP_EQ(func(CFPT(-0.0 + 0.0i)), 0.0);
     EXPECT_FP_EQ(func(CFPT(0.0 - 0.0i)), 0.0);
     EXPECT_FP_EQ(func(CFPT(-0.0 - 0.0i)), -0.0);
+    EXPECT_FP_EQ(func(CFPT(0.0)), 0.0);
+    EXPECT_FP_EQ(func(CFPT(-0.0)), -0.0);
+    EXPECT_FP_EQ(func(CFPT(0.0i)), 0.0);
+    EXPECT_FP_EQ(func(CFPT(-0.0i)), -0.0);
   }
 
   void testRoundedNumbers(CRealFunc func) {

libc/test/src/complex/ConjTest.h

@@ -70,10 +70,17 @@ class ConjTest : public LIBC_NAMESPACE::testing::FEnvSafeTest {
                   CFPT(121.121 - zero * 1.0i));
     EXPECT_CFP_EQ(func(CFPT(0.0 - 0.0i)), CFPT(0.0 + 0.0i));
     EXPECT_CFP_EQ(func(CFPT(0.0 + 0.0i)), CFPT(0.0 - 0.0i));
-    EXPECT_CFP_EQ(func(CFPT(-0.0 - 0.0i)), CFPT(-0.0 + 0.0i));
+    // This test passes because the conjugate of -0.0 - 0.0i is -0.0 + 0.0i
+    // but -0.0 + 0.0i is actually CMPLX(-0.0, 0.0) + CMPLX(0.0, 0.0) = 0.0 + 0.0i
+    // so to represent -0.0 + 0.0i, we just write -0.0
+    EXPECT_CFP_EQ(func(CFPT(-0.0 - 0.0i)), CFPT(-0.0));
     // This test passes because -0.0 + 0.0i is actually
     // CMPLX(-0.0, 0.0) + CMPLX(0.0, 0.0) = CMPLX(-0.0 + 0.0, 0.0) = 0.0 + 0.0i
     EXPECT_CFP_EQ(func(CFPT(-0.0 + 0.0i)), CFPT(0.0 - 0.0i));
+    EXPECT_CFP_EQ(func(CFPT(0.0)), CFPT(0.0 - 0.0i));
+    EXPECT_CFP_EQ(func(CFPT(-0.0)), CFPT(-0.0 - 0.0i));
+    EXPECT_CFP_EQ(func(CFPT(0.0i)), CFPT(0.0 - 0.0i));
+    EXPECT_CFP_EQ(func(CFPT(-0.0i)), CFPT(-0.0));
   }
 
   void testRoundedNumbers(ConjFunc func) {