Merge "Fixed bug in LICM"
diff --git a/compiler/optimizing/licm.cc b/compiler/optimizing/licm.cc
index eb2d18d..f0086fb 100644
--- a/compiler/optimizing/licm.cc
+++ b/compiler/optimizing/licm.cc
@@ -120,17 +120,17 @@
}
DCHECK(!loop_info->IsIrreducible());
- // We can move an instruction that can throw only if it is the first
- // throwing instruction in the loop. Note that the first potentially
- // throwing instruction encountered that is not hoisted stops this
- // optimization. Non-throwing instruction can still be hoisted.
- bool found_first_non_hoisted_throwing_instruction_in_loop = !inner->IsLoopHeader();
+ // We can move an instruction that can throw only as long as it is the first visible
+ // instruction (throw or write) in the loop. Note that the first potentially visible
+ // instruction that is not hoisted stops this optimization. Non-throwing instructions,
+ // on the other hand, can still be hoisted.
+ bool found_first_non_hoisted_visible_instruction_in_loop = !inner->IsLoopHeader();
for (HInstructionIterator inst_it(inner->GetInstructions());
!inst_it.Done();
inst_it.Advance()) {
HInstruction* instruction = inst_it.Current();
if (instruction->CanBeMoved()
- && (!instruction->CanThrow() || !found_first_non_hoisted_throwing_instruction_in_loop)
+ && (!instruction->CanThrow() || !found_first_non_hoisted_visible_instruction_in_loop)
&& !instruction->GetSideEffects().MayDependOn(loop_effects)
&& InputsAreDefinedBeforeLoop(instruction)) {
// We need to update the environment if the instruction has a loop header
@@ -142,10 +142,10 @@
}
instruction->MoveBefore(pre_header->GetLastInstruction());
MaybeRecordStat(MethodCompilationStat::kLoopInvariantMoved);
- } else if (instruction->CanThrow()) {
- // If `instruction` can throw, we cannot move further instructions
- // that can throw as well.
- found_first_non_hoisted_throwing_instruction_in_loop = true;
+ } else if (instruction->CanThrow() || instruction->DoesAnyWrite()) {
+ // If `instruction` can do something visible (throw or write),
+ // we cannot move further instructions that can throw.
+ found_first_non_hoisted_visible_instruction_in_loop = true;
}
}
}
diff --git a/test/625-checker-licm-regressions/expected.txt b/test/625-checker-licm-regressions/expected.txt
new file mode 100644
index 0000000..b0aad4d
--- /dev/null
+++ b/test/625-checker-licm-regressions/expected.txt
@@ -0,0 +1 @@
+passed
diff --git a/test/625-checker-licm-regressions/info.txt b/test/625-checker-licm-regressions/info.txt
new file mode 100644
index 0000000..10480df
--- /dev/null
+++ b/test/625-checker-licm-regressions/info.txt
@@ -0,0 +1 @@
+Regression tests on LICM.
diff --git a/test/625-checker-licm-regressions/src/Main.java b/test/625-checker-licm-regressions/src/Main.java
new file mode 100644
index 0000000..cc1e07c
--- /dev/null
+++ b/test/625-checker-licm-regressions/src/Main.java
@@ -0,0 +1,66 @@
+/*
+ * 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 LICM.
+ */
+public class Main {
+
+ static int sA;
+
+ //
+ // We cannot hoist the null check (can throw) above the field
+ // assignment (has write side effects) because that would result
+ // in throwing an exception before the assignment is done.
+ //
+ /// CHECK-START: void Main.foo(int[]) licm (before)
+ /// CHECK-DAG: LoadClass loop:<<Loop:B\d+>> outer_loop:none
+ /// CHECK-DAG: StaticFieldSet loop:<<Loop>> outer_loop:none
+ /// CHECK-DAG: NullCheck loop:<<Loop>> outer_loop:none
+ /// CHECK-DAG: ArrayLength loop:<<Loop>> outer_loop:none
+ //
+ /// CHECK-START: void Main.foo(int[]) licm (after)
+ /// CHECK-DAG: LoadClass loop:none
+ /// CHECK-DAG: StaticFieldSet loop:<<Loop:B\d+>> outer_loop:none
+ /// CHECK-DAG: NullCheck loop:<<Loop>> outer_loop:none
+ /// CHECK-DAG: ArrayLength loop:<<Loop>> outer_loop:none
+ //
+ /// CHECK-START: void Main.foo(int[]) licm (after)
+ /// CHECK-NOT: LoadClass loop:{{B\d+}} outer_loop:none
+ static void foo(int[] arr) {
+ int j = 0;
+ do {
+ sA = 1;
+ } while (j < arr.length);
+ }
+
+ public static void main(String[] args) {
+ sA = 0;
+ try {
+ foo(null);
+ } catch (Exception e) {
+ }
+ expectEquals(1, sA);
+
+ System.out.println("passed");
+ }
+
+ private static void expectEquals(int expected, int result) {
+ if (expected != result) {
+ throw new Error("Expected: " + expected + ", found: " + result);
+ }
+ }
+}