[turbofan] Implement rounding of floats on x64 and ia32 without sse4.1.

test/cctest/compiler/test-run-machops.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 <cmath>
 #include <functional>
 #include <limits>
 
 #include "src/base/bits.h"
 #include "src/base/utils/random-number-generator.h"
@@ skipping 5401 matching lines @@
 TEST(RunFloat32RoundDown) {
   BufferedRawMachineAssemblerTester<float> m(MachineType::Float32());
   if (!m.machine()->Float32RoundDown().IsSupported()) return;
 
   m.Return(m.Float32RoundDown(m.Parameter(0)));
 
   FOR_FLOAT32_INPUTS(i) { CheckFloatEq(floorf(*i), m.Call(*i)); }
 }
 
 
+TEST(RunFloat32RoundDownMinusZero) {
+  BufferedRawMachineAssemblerTester<float> m(MachineType::Float32());
+  if (!m.machine()->Float32RoundDown().IsSupported()) return;
+
+  m.Return(m.Float32RoundDown(m.Parameter(0)));
+  int32_t expected = bit_cast<int32_t>(-0.0f);
+  int32_t result = bit_cast<int32_t>(m.Call(-0.0f));
+  CHECK_EQ(expected, result);
+}
+
+
+TEST(RunFloat64RoundDownMinusZero) {
+  BufferedRawMachineAssemblerTester<double> m(MachineType::Float64());
+  if (!m.machine()->Float64RoundDown().IsSupported()) return;
+
+  m.Return(m.Float64RoundDown(m.Parameter(0)));
+  int64_t expected = bit_cast<int64_t>(-0.0);
+  int64_t result = bit_cast<int64_t>(m.Call(-0.0));
+  CHECK_EQ(expected, result);
+}
+
+
 TEST(RunFloat64RoundDown1) {
   BufferedRawMachineAssemblerTester<double> m(MachineType::Float64());
   if (!m.machine()->Float64RoundDown().IsSupported()) return;
 
   m.Return(m.Float64RoundDown(m.Parameter(0)));
 
   FOR_FLOAT64_INPUTS(i) { CheckDoubleEq(floor(*i), m.Call(*i)); }
 }
 
 
@@ skipping 651 matching lines @@
   Node* call = r.AddNode(r.common()->Call(desc), phi);
   r.Return(call);
 
   CHECK_EQ(33, r.Call(1));
   CHECK_EQ(44, r.Call(0));
 }
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8