| /* |
| * Copyright (C) 2015 The Android Open Source Project |
| * |
| * Licensed under the Apache License, Version 2.0 (the "License"); |
| * you may not use this file except in compliance with the License. |
| * You may obtain a copy of the License at |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, software |
| * distributed under the License is distributed on an "AS IS" BASIS, |
| * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| * See the License for the specific language governing permissions and |
| * limitations under the License. |
| */ |
| |
| public class Main { |
| |
| // CHECK-START: int Main.sieve(int) BCE (before) |
| // CHECK: BoundsCheck |
| // CHECK: ArraySet |
| // CHECK: BoundsCheck |
| // CHECK: ArrayGet |
| // CHECK: BoundsCheck |
| // CHECK: ArraySet |
| |
| // CHECK-START: int Main.sieve(int) BCE (after) |
| // CHECK-NOT: BoundsCheck |
| // CHECK: ArraySet |
| // CHECK-NOT: BoundsCheck |
| // CHECK: ArrayGet |
| // CHECK: BoundsCheck |
| // CHECK: ArraySet |
| |
| static int sieve(int size) { |
| int primeCount = 0; |
| boolean[] flags = new boolean[size + 1]; |
| for (int i = 1; i < size; i++) flags[i] = true; // Can eliminate. |
| for (int i = 2; i < size; i++) { |
| if (flags[i]) { // Can eliminate. |
| primeCount++; |
| for (int k = i + 1; k <= size; k += i) |
| flags[k - 1] = false; // Can't eliminate yet due to (k+i) may overflow. |
| } |
| } |
| return primeCount; |
| } |
| |
| // CHECK-START: void Main.narrow(int[], int) BCE (before) |
| // CHECK: BoundsCheck |
| // CHECK: ArraySet |
| // CHECK: BoundsCheck |
| // CHECK: ArraySet |
| // CHECK: BoundsCheck |
| // CHECK: ArraySet |
| |
| // CHECK-START: void Main.narrow(int[], int) BCE (after) |
| // CHECK-NOT: BoundsCheck |
| // CHECK: ArraySet |
| // CHECK-NOT: BoundsCheck |
| // CHECK: ArraySet |
| // CHECK: BoundsCheck |
| // CHECK: ArraySet |
| |
| static void narrow(int array[], int offset) { |
| if (offset < 0) { |
| return; |
| } |
| if (offset < array.length) { |
| // offset is in range [0, array.length-1]. |
| // Bounds check can be eliminated. |
| array[offset] = 1; |
| |
| int biased_offset1 = offset + 1; |
| // biased_offset1 is in range [1, array.length]. |
| if (biased_offset1 < array.length) { |
| // biased_offset1 is in range [1, array.length-1]. |
| // Bounds check can be eliminated. |
| array[biased_offset1] = 1; |
| } |
| |
| int biased_offset2 = offset + 0x70000000; |
| // biased_offset2 is in range [0x70000000, array.length-1+0x70000000]. |
| // It may overflow and be negative. |
| if (biased_offset2 < array.length) { |
| // Even with this test, biased_offset2 can be negative so we can't |
| // eliminate this bounds check. |
| array[biased_offset2] = 1; |
| } |
| } |
| } |
| |
| public static void main(String[] args) { |
| sieve(20); |
| } |
| } |