[turbofan] Push TruncateFloat64ToInt32 into phis.

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 ffc0d5e661c068c4beb7aa3fe8d1f5724b0577d9..a62216dfcdf283e512f215909895c490abf9eb8e 100644
--- a/test/unittests/compiler/machine-operator-reducer-unittest.cc
+++ b/test/unittests/compiler/machine-operator-reducer-unittest.cc
@@ -455,6 +455,20 @@ TEST_F(MachineOperatorReducerTest, TruncateFloat64ToInt32WithConstant) {
 }
 
 
+TEST_F(MachineOperatorReducerTest, TruncateFloat64ToInt32WithPhi) {
+  Node* const p0 = Parameter(0);
+  Node* const p1 = Parameter(1);
+  Node* const merge = graph()->start();
+  Reduction reduction = Reduce(graph()->NewNode(
+      machine()->TruncateFloat64ToInt32(),
+      graph()->NewNode(common()->Phi(kMachFloat64, 2), p0, p1, merge)));
+  ASSERT_TRUE(reduction.Changed());
+  EXPECT_THAT(reduction.replacement(),
+              IsPhi(kMachInt32, IsTruncateFloat64ToInt32(p0),
+                    IsTruncateFloat64ToInt32(p1), merge));
+}
+
+
 // -----------------------------------------------------------------------------
 // TruncateInt64ToInt32