[turbofan] Extend optimization of flooring integer division.

test/unittests/compiler/typer-unittest.cc

 // Copyright 2015 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 <functional>
 
 #include "src/codegen.h"
 #include "src/compiler/js-operator.h"
 #include "src/compiler/node-properties.h"
 #include "src/compiler/operator-properties.h"
@@ skipping 147 matching lines @@
       Type* expected_type = TypeBinaryOp(op, r1, r2);
       for (int i = 0; i < 10; i++) {
         double x1 = RandomInt(r1->AsRange());
         double x2 = RandomInt(r2->AsRange());
         double result_value = opfun(x1, x2);
         Type* result_type = Type::NewConstant(
             isolate()->factory()->NewNumber(result_value), zone());
         EXPECT_TRUE(result_type->Is(expected_type));
       }
     }
+    // Test extreme cases.
+    double x1 = +1e-308;
+    double x2 = -1e-308;
+    Type* r1 = Type::NewConstant(isolate()->factory()->NewNumber(x1), zone());
+    Type* r2 = Type::NewConstant(isolate()->factory()->NewNumber(x2), zone());
+    Type* expected_type = TypeBinaryOp(op, r1, r2);
+    double result_value = opfun(x1, x2);
+    Type* result_type = Type::NewConstant(
+        isolate()->factory()->NewNumber(result_value), zone());
+    EXPECT_TRUE(result_type->Is(expected_type));
   }
 
   template <class BinaryFunction>
   void TestBinaryCompareOp(const Operator* op, BinaryFunction opfun) {
     for (int i = 0; i < 100; ++i) {
       Type* r1 = RandomRange();
       Type* r2 = RandomRange();
       Type* expected_type = TypeBinaryOp(op, r1, r2);
       for (int i = 0; i < 10; i++) {
         double x1 = RandomInt(r1->AsRange());
@@ skipping 206 matching lines @@
 #define TEST_BINARY_MONOTONICITY(name)                                   \
   TEST_F(TyperTest, Monotonicity_##name) {                               \
     TestBinaryMonotonicity(javascript_.name(BinaryOperationHint::kAny)); \
   }
 TEST_BINARY_MONOTONICITY(Add)
 #undef TEST_BINARY_MONOTONICITY
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8