[builtins] Introduce proper Float64Exp operator.

test/unittests/compiler/machine-operator-reducer-unittest.cc

Index: test/unittests/compiler/machine-operator-reducer-unittest.cc
diff --git a/test/unittests/compiler/machine-operator-reducer-unittest.cc b/test/unittests/compiler/machine-operator-reducer-unittest.cc
index 9d7482af76df973f45b98cac3391179fa43cdecd..2a161ce82d80da50c9d641493a22ec0f40bac654 100644
--- a/test/unittests/compiler/machine-operator-reducer-unittest.cc
+++ b/test/unittests/compiler/machine-operator-reducer-unittest.cc
@@ -1448,6 +1448,19 @@ TEST_F(MachineOperatorReducerTest, Float64Atan2WithNaN) {
 }
 
 // -----------------------------------------------------------------------------
+// Float64Exp
+
+TEST_F(MachineOperatorReducerTest, Float64ExpWithConstant) {
+  TRACED_FOREACH(double, x, kFloat64Values) {
+    Reduction const r =
+        Reduce(graph()->NewNode(machine()->Float64Exp(), Float64Constant(x)));
+    ASSERT_TRUE(r.Changed());
+    EXPECT_THAT(r.replacement(),
+                IsFloat64Constant(NanSensitiveDoubleEq(base::ieee754::exp(x))));
+  }
+}
+
+// -----------------------------------------------------------------------------
 // Float64Log
 
 TEST_F(MachineOperatorReducerTest, Float64LogWithConstant) {