Omit declarations when LLVM_INTEGRATE_LIBC is off and fix default rounding mode declaration.

Author: lntue

llvm/include/llvm/ADT/APFloat.h

@@ -1523,9 +1523,12 @@ class APFloat : public APFloatBase {
   friend int ilogb(const APFloat &Arg) { return ilogb(Arg.getIEEE()); }
   friend APFloat scalbn(APFloat X, int Exp, roundingMode RM);
   friend APFloat frexp(const APFloat &X, int &Exp, roundingMode RM);
-  friend APFloat exp(const APFloat &X, roundingMode RM);
   friend IEEEFloat;
   friend DoubleAPFloat;
+
+#ifdef LLVM_INTEGRATE_LIBC
+  friend APFloat exp(const APFloat &X, roundingMode RM);
+#endif // LLVM_INTEGRATE_LIBC)
 };
 
 static_assert(sizeof(APFloat) == sizeof(detail::IEEEFloat),
@@ -1659,9 +1662,11 @@ inline APFloat maximumnum(const APFloat &A, const APFloat &B) {
   return A < B ? B : A;
 }
 
+#ifdef LLVM_INTEGRATE_LIBC
 /// Implement IEEE 754-2019 exp functions.
 LLVM_READONLY
-APFloat exp(const APFloat &X, RoundingMode RM);
+APFloat exp(const APFloat &X, RoundingMode RM = APFloat::rmNearestTiesToEven);
+#endif // LLVM_INTEGRATE_LIBC
 
 inline raw_ostream &operator<<(raw_ostream &OS, const APFloat &V) {
   V.print(OS);

llvm/lib/Support/APFloat.cpp

@@ -5621,8 +5621,7 @@ static constexpr int getFEnvRoundingMode(llvm::RoundingMode rm) {
   };
 }
 
-APFloat exp(const APFloat &X,
-            RoundingMode rounding_mode = APFloat::rmNearestTiesToEven) {
+APFloat exp(const APFloat &X, RoundingMode rounding_mode) {
   assert((&X.getSemantics() == (const llvm::fltSemantics *)&semIEEEsingle) &&
          "Float semantics is not IEEEsingle");
   if (&X.getSemantics() == (const llvm::fltSemantics *)&semIEEEsingle) {

llvm/unittests/ADT/APFloatTest.cpp

@@ -8409,7 +8409,7 @@ TEST(APFloatTest, expf) {
   EXPECT_EQ(1.0f, llvm::exp(APFloat::getSmallest(APFloat::IEEEsingle(), false),
                             APFloat::rmNearestTiesToEven)
                       .convertToFloat());
-  EXPECT_EQ(0x1.000002p0,
+  EXPECT_EQ(0x1.000002p0f,
             llvm::exp(APFloat::getSmallest(APFloat::IEEEsingle(), false),
                       APFloat::rmTowardPositive)
                 .convertToFloat());
@@ -8419,6 +8419,17 @@ TEST(APFloatTest, expf) {
   EXPECT_EQ(1.0f, llvm::exp(APFloat::getSmallest(APFloat::IEEEsingle(), false),
                             APFloat::rmTowardZero)
                       .convertToFloat());
+  // Default rounding mode.
+  // exp(-1)
+  EXPECT_EQ(0x1.78b564p-2f, llvm::exp(APFloat(-1.0f)).convertToFloat());
+  EXPECT_EQ(
+      0x1.78b564p-2f,
+      llvm::exp(APFloat(-1.0f), APFloat::rmTowardPositive).convertToFloat());
+  EXPECT_EQ(
+      0x1.78b562p-2f,
+      llvm::exp(APFloat(-1.0f), APFloat::rmTowardNegative).convertToFloat());
+  EXPECT_EQ(0x1.78b562p-2f,
+            llvm::exp(APFloat(-1.0f), APFloat::rmTowardZero).convertToFloat());
 }
 #endif // LLVM_INTEGRATE_LIBC