[builtins] Introduce proper Float64Log1p operator.

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

 // Copyright 2014 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "src/compiler/machine-operator-reducer.h"
 #include "src/base/bits.h"
 #include "src/base/division-by-constant.h"
 #include "src/base/ieee754.h"
 #include "src/compiler/js-graph.h"
 #include "src/compiler/typer.h"
@@ skipping 1396 matching lines @@
   TRACED_FOREACH(double, x, kFloat64Values) {
     Reduction const r =
         Reduce(graph()->NewNode(machine()->Float64Log(), Float64Constant(x)));
     ASSERT_TRUE(r.Changed());
     EXPECT_THAT(r.replacement(),
                 IsFloat64Constant(NanSensitiveDoubleEq(base::ieee754::log(x))));
   }
 }
 
 // -----------------------------------------------------------------------------
+// Float64Log1p
+
+TEST_F(MachineOperatorReducerTest, Float64Log1pWithConstant) {
+  TRACED_FOREACH(double, x, kFloat64Values) {
+    Reduction const r =
+        Reduce(graph()->NewNode(machine()->Float64Log1p(), Float64Constant(x)));
+    ASSERT_TRUE(r.Changed());
+    EXPECT_THAT(
+        r.replacement(),
+        IsFloat64Constant(NanSensitiveDoubleEq(base::ieee754::log1p(x))));
+  }
+}
+
+// -----------------------------------------------------------------------------
 // Float64InsertLowWord32
 
 TEST_F(MachineOperatorReducerTest, Float64InsertLowWord32WithConstant) {
   TRACED_FOREACH(double, x, kFloat64Values) {
     TRACED_FOREACH(uint32_t, y, kUint32Values) {
       Reduction const r =
           Reduce(graph()->NewNode(machine()->Float64InsertLowWord32(),
                                   Float64Constant(x), Uint32Constant(y)));
       ASSERT_TRUE(r.Changed());
       EXPECT_THAT(
@@ skipping 230 matching lines @@
     Reduction r = Reduce(node);
     ASSERT_TRUE(r.Changed());
     EXPECT_THAT(r.replacement(),
                 IsStore(rep, base, index, value, effect, control));
   }
 }
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8