[turbofan] Add constant-folding for CheckedFloat64ToInt32.

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

Index: test/unittests/compiler/simplified-operator-reducer-unittest.cc
diff --git a/test/unittests/compiler/simplified-operator-reducer-unittest.cc b/test/unittests/compiler/simplified-operator-reducer-unittest.cc
index 6f37609f3a0e5559c3b0a06d810653ab05efaae2..f5ae91d7c1482df0a31bec3db5ad60a8307aa008 100644
--- a/test/unittests/compiler/simplified-operator-reducer-unittest.cc
+++ b/test/unittests/compiler/simplified-operator-reducer-unittest.cc
@@ -336,6 +336,22 @@ TEST_F(SimplifiedOperatorReducerTest, TruncateTaggedToWord32WithConstant) {
 }
 
 // -----------------------------------------------------------------------------
+// CheckedFloat64ToInt32
+
+TEST_F(SimplifiedOperatorReducerTest, CheckedFloat64ToInt32WithConstant) {
+  Node* effect = graph()->start();
+  Node* control = graph()->start();
+  TRACED_FOREACH(int32_t, n, kInt32Values) {
+    Reduction r = Reduce(
+        graph()->NewNode(simplified()->CheckedFloat64ToInt32(
+                             CheckForMinusZeroMode::kDontCheckForMinusZero),
+                         Float64Constant(n), effect, control));
+    ASSERT_TRUE(r.Changed());
+    EXPECT_THAT(r.replacement(), IsInt32Constant(n));
+  }
+}
+
+// -----------------------------------------------------------------------------
 // CheckHeapObject
 
 TEST_F(SimplifiedOperatorReducerTest, CheckHeapObjectWithChangeBitToTagged) {