[builtins] Introduce proper Float64Tan 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 b9de98046001fe2f53958ba4592b62a633f82919..39306b521879997f94a8180e75bf6b5ad13038b9 100644
--- a/test/unittests/compiler/machine-operator-reducer-unittest.cc
+++ b/test/unittests/compiler/machine-operator-reducer-unittest.cc
@@ -1530,6 +1530,19 @@ TEST_F(MachineOperatorReducerTest, Float64SinWithConstant) {
 }
 
 // -----------------------------------------------------------------------------
+// Float64Tan
+
+TEST_F(MachineOperatorReducerTest, Float64TanWithConstant) {
+  TRACED_FOREACH(double, x, kFloat64Values) {
+    Reduction const r =
+        Reduce(graph()->NewNode(machine()->Float64Tan(), Float64Constant(x)));
+    ASSERT_TRUE(r.Changed());
+    EXPECT_THAT(r.replacement(),
+                IsFloat64Constant(NanSensitiveDoubleEq(base::ieee754::tan(x))));
+  }
+}
+
+// -----------------------------------------------------------------------------
 // Float64InsertLowWord32
 
 TEST_F(MachineOperatorReducerTest, Float64InsertLowWord32WithConstant) {