[builtins] Introduce proper Float64Exp operator.

test/cctest/compiler/test-run-machops.cc

Index: test/cctest/compiler/test-run-machops.cc
diff --git a/test/cctest/compiler/test-run-machops.cc b/test/cctest/compiler/test-run-machops.cc
index ab5c7d90934bb21fe4a0fd7da59d4649c541619e..1f497f1a2430441758a9be0999c5eb8970a52428 100644
--- a/test/cctest/compiler/test-run-machops.cc
+++ b/test/cctest/compiler/test-run-machops.cc
@@ -5517,6 +5517,19 @@ TEST(RunFloat64Atan2) {
   }
 }
 
+TEST(RunFloat64Exp) {
+  BufferedRawMachineAssemblerTester<double> m(MachineType::Float64());
+  m.Return(m.Float64Exp(m.Parameter(0)));
+  CHECK(std::isnan(m.Call(std::numeric_limits<double>::quiet_NaN())));
+  CHECK(std::isnan(m.Call(std::numeric_limits<double>::signaling_NaN())));
+  CHECK_EQ(0.0, m.Call(-std::numeric_limits<double>::infinity()));
+  CHECK_DOUBLE_EQ(1.0, m.Call(-0.0));
+  CHECK_DOUBLE_EQ(1.0, m.Call(0.0));
+  CHECK_DOUBLE_EQ(std::numeric_limits<double>::infinity(),
+                  m.Call(std::numeric_limits<double>::infinity()));
+  FOR_FLOAT64_INPUTS(i) { CHECK_DOUBLE_EQ(ieee754::exp(*i), m.Call(*i)); }
+}
+
 TEST(RunFloat64Log) {
   BufferedRawMachineAssemblerTester<double> m(MachineType::Float64());
   m.Return(m.Float64Log(m.Parameter(0)));