Add minnum / maxnum to APFloat

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@219475 91177308-0d34-0410-b5e6-96231b3b80d8

include/llvm/ADT/APFloat.h

@@ -649,6 +649,28 @@ class APFloat {
 hash_code hash_value(const APFloat &Arg);
 APFloat scalbn(APFloat X, int Exp);
 
+/// Implements IEEE minNum semantics. Returns the smaller of the 2 arguments if
+/// both are not NaN. If either argument is a NaN, returns the other argument.
+LLVM_READONLY
+inline APFloat minnum(const APFloat &A, const APFloat &B) {
+  if (A.isNaN())
+    return B;
+  if (B.isNaN())
+    return A;
+  return (B.compare(A) == APFloat::cmpLessThan) ? B : A;
+}
+
+/// Implements IEEE maxNum semantics. Returns the larger of the 2 arguments if
+/// both are not NaN. If either argument is a NaN, returns the other argument.
+LLVM_READONLY
+inline APFloat maxnum(const APFloat &A, const APFloat &B) {
+  if (A.isNaN())
+    return B;
+  if (B.isNaN())
+    return A;
+  return (A.compare(B) == APFloat::cmpLessThan) ? B : A;
+}
+
 } // namespace llvm
 
 #endif // LLVM_ADT_APFLOAT_H

unittests/ADT/APFloatTest.cpp

@@ -476,6 +476,28 @@ TEST(APFloatTest, FMA) {
   }
 }
 
+TEST(APFloatTest, MinNum) {
+  APFloat f1(1.0);
+  APFloat f2(2.0);
+  APFloat nan = APFloat::getNaN(APFloat::IEEEdouble);
+
+  EXPECT_EQ(1.0, minnum(f1, f2).convertToDouble());
+  EXPECT_EQ(1.0, minnum(f2, f1).convertToDouble());
+  EXPECT_EQ(1.0, minnum(f1, nan).convertToDouble());
+  EXPECT_EQ(1.0, minnum(nan, f1).convertToDouble());
+}
+
+TEST(APFloatTest, MaxNum) {
+  APFloat f1(1.0);
+  APFloat f2(2.0);
+  APFloat nan = APFloat::getNaN(APFloat::IEEEdouble);
+
+  EXPECT_EQ(2.0, maxnum(f1, f2).convertToDouble());
+  EXPECT_EQ(2.0, maxnum(f2, f1).convertToDouble());
+  EXPECT_EQ(1.0, maxnum(f1, nan).convertToDouble());
+  EXPECT_EQ(1.0, minnum(nan, f1).convertToDouble());
+}
+
 TEST(APFloatTest, Denormal) {
   APFloat::roundingMode rdmd = APFloat::rmNearestTiesToEven;