[ADT] Add basic operator overloads for arithmetic to APFloat to make

code using it more readable.

Also add a copySign static function that works more like the standard
function by accepting the value and sign-carying value as arguments.

No interesting logic here, but tests added to cover the basic API
additions and make sure they do something plausible.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@219453 91177308-0d34-0410-b5e6-96231b3b80d8

include/llvm/ADT/APFloat.h

@@ -304,6 +304,38 @@ class APFloat {
   /// IEEE-754R 5.3.1: nextUp/nextDown.
   opStatus next(bool nextDown);
 
+  /// \brief Operator+ overload which provides the default
+  /// \c nmNearestTiesToEven rounding mode and *no* error checking.
+  APFloat operator+(const APFloat &RHS) const {
+    APFloat Result = *this;
+    Result.add(RHS, rmNearestTiesToEven);
+    return Result;
+  }
+
+  /// \brief Operator- overload which provides the default
+  /// \c nmNearestTiesToEven rounding mode and *no* error checking.
+  APFloat operator-(const APFloat &RHS) const {
+    APFloat Result = *this;
+    Result.subtract(RHS, rmNearestTiesToEven);
+    return Result;
+  }
+
+  /// \brief Operator* overload which provides the default
+  /// \c nmNearestTiesToEven rounding mode and *no* error checking.
+  APFloat operator*(const APFloat &RHS) const {
+    APFloat Result = *this;
+    Result.multiply(RHS, rmNearestTiesToEven);
+    return Result;
+  }
+
+  /// \brief Operator/ overload which provides the default
+  /// \c nmNearestTiesToEven rounding mode and *no* error checking.
+  APFloat operator/(const APFloat &RHS) const {
+    APFloat Result = *this;
+    Result.divide(RHS, rmNearestTiesToEven);
+    return Result;
+  }
+
   /// @}
 
   /// \name Sign operations.
@@ -313,6 +345,13 @@ class APFloat {
   void clearSign();
   void copySign(const APFloat &);
 
+  /// \brief A static helper to produce a copy of an APFloat value with its sign
+  /// copied from some other APFloat.
+  static APFloat copySign(APFloat Value, const APFloat &Sign) {
+    Value.copySign(Sign);
+    return std::move(Value);
+  }
+
   /// @}
 
   /// \name Conversions

unittests/ADT/APFloatTest.cpp

@@ -1342,6 +1342,17 @@ TEST(APFloatTest, getZero) {
   }
 }
 
+TEST(APFloatTest, copySign) {
+  EXPECT_TRUE(APFloat(-42.0).bitwiseIsEqual(
+      APFloat::copySign(APFloat(42.0), APFloat(-1.0))));
+  EXPECT_TRUE(APFloat(42.0).bitwiseIsEqual(
+      APFloat::copySign(APFloat(-42.0), APFloat(1.0))));
+  EXPECT_TRUE(APFloat(-42.0).bitwiseIsEqual(
+      APFloat::copySign(APFloat(-42.0), APFloat(-1.0))));
+  EXPECT_TRUE(APFloat(42.0).bitwiseIsEqual(
+      APFloat::copySign(APFloat(42.0), APFloat(1.0))));
+}
+
 TEST(APFloatTest, convert) {
   bool losesInfo;
   APFloat test(APFloat::IEEEdouble, "1.0");
@@ -2671,4 +2682,13 @@ TEST(APFloatTest, divide) {
   }
 }
 
+TEST(APFloatTest, operatorOverloads) {
+  // This is mostly testing that these operator overloads compile.
+  APFloat One = APFloat(APFloat::IEEEsingle, "0x1p+0");
+  APFloat Two = APFloat(APFloat::IEEEsingle, "0x2p+0");
+  EXPECT_TRUE(Two.bitwiseIsEqual(One + One));
+  EXPECT_TRUE(One.bitwiseIsEqual(Two - One));
+  EXPECT_TRUE(Two.bitwiseIsEqual(One * Two));
+  EXPECT_TRUE(One.bitwiseIsEqual(Two / Two));
+}
 }