Avoid visiting just eliminated bounds check.
Test: test-art-host
Bug: 32547652
Change-Id: Ifaed3d4eee08c6d044a41ade6c1ee73989489110
diff --git a/compiler/optimizing/bounds_check_elimination.cc b/compiler/optimizing/bounds_check_elimination.cc
index d2357a5..7dc094b 100644
--- a/compiler/optimizing/bounds_check_elimination.cc
+++ b/compiler/optimizing/bounds_check_elimination.cc
@@ -548,7 +548,21 @@
void VisitBasicBlock(HBasicBlock* block) OVERRIDE {
DCHECK(!IsAddedBlock(block));
first_index_bounds_check_map_.clear();
- HGraphVisitor::VisitBasicBlock(block);
+ // Visit phis and instructions using a safe iterator. The iteration protects
+ // against deleting the current instruction during iteration. However, it
+ // must advance next_ if that instruction is deleted during iteration.
+ for (HInstruction* instruction = block->GetFirstPhi(); instruction != nullptr;) {
+ DCHECK(instruction->IsInBlock());
+ next_ = instruction->GetNext();
+ instruction->Accept(this);
+ instruction = next_;
+ }
+ for (HInstruction* instruction = block->GetFirstInstruction(); instruction != nullptr;) {
+ DCHECK(instruction->IsInBlock());
+ next_ = instruction->GetNext();
+ instruction->Accept(this);
+ instruction = next_;
+ }
// We should never deoptimize from an osr method, otherwise we might wrongly optimize
// code dominated by the deoptimization.
if (!GetGraph()->IsCompilingOsr()) {
@@ -1798,7 +1812,12 @@
}
/** Helper method to replace an instruction with another instruction. */
- static void ReplaceInstruction(HInstruction* instruction, HInstruction* replacement) {
+ void ReplaceInstruction(HInstruction* instruction, HInstruction* replacement) {
+ // Safe iteration.
+ if (instruction == next_) {
+ next_ = next_->GetNext();
+ }
+ // Replace and remove.
instruction->ReplaceWith(replacement);
instruction->GetBlock()->RemoveInstruction(instruction);
}
@@ -1831,6 +1850,9 @@
// Range analysis based on induction variables.
InductionVarRange induction_range_;
+ // Safe iteration.
+ HInstruction* next_;
+
DISALLOW_COPY_AND_ASSIGN(BCEVisitor);
};
diff --git a/test/622-checker-bce-regressions/expected.txt b/test/622-checker-bce-regressions/expected.txt
new file mode 100644
index 0000000..b0aad4d
--- /dev/null
+++ b/test/622-checker-bce-regressions/expected.txt
@@ -0,0 +1 @@
+passed
diff --git a/test/622-checker-bce-regressions/info.txt b/test/622-checker-bce-regressions/info.txt
new file mode 100644
index 0000000..a753dfa
--- /dev/null
+++ b/test/622-checker-bce-regressions/info.txt
@@ -0,0 +1 @@
+Regression tests on BCE.
diff --git a/test/622-checker-bce-regressions/src/Main.java b/test/622-checker-bce-regressions/src/Main.java
new file mode 100644
index 0000000..6ba2644
--- /dev/null
+++ b/test/622-checker-bce-regressions/src/Main.java
@@ -0,0 +1,55 @@
+/*
+ * Copyright (C) 2016 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.
+ */
+
+/**
+ * Regression tests for BCE.
+ */
+public class Main {
+
+ static int[] array = new int[10];
+
+ /// CHECK-START: int Main.doNotVisitAfterForwardBCE(int[]) BCE (before)
+ /// CHECK-DAG: BoundsCheck loop:<<Loop:B\d+>> outer_loop:none
+ /// CHECK-DAG: BoundsCheck loop:<<Loop>> outer_loop:none
+ //
+ /// CHECK-START: int Main.doNotVisitAfterForwardBCE(int[]) BCE (after)
+ /// CHECK-NOT: BoundsCheck
+ static int doNotVisitAfterForwardBCE(int[] a) {
+ if (a == null) {
+ throw new Error("Null");
+ }
+ int k = 0;
+ int j = 0;
+ for (int i = 1; i < 10; i++) {
+ j = i - 1;
+ // b/32547652: after DCE, bounds checks become consecutive,
+ // and second should not be revisited after forward BCE.
+ k = a[i] + a[i - 1];
+ }
+ return j;
+ }
+
+ public static void main(String[] args) {
+ expectEquals(8, doNotVisitAfterForwardBCE(array));
+ System.out.println("passed");
+ }
+
+ private static void expectEquals(int expected, int result) {
+ if (expected != result) {
+ throw new Error("Expected: " + expected + ", found: " + result);
+ }
+ }
+}
