Avoid calls to the O(n) LinkedList.get() in BasicBlockInstructionsEquivalence
Noticed this when looking at replacing LinkedList in BasicBlock
Bug: None
Change-Id: I97543d1c93ca7054b3015ca9412ffef3d23e4649
diff --git a/src/main/java/com/android/tools/r8/ir/optimize/BasicBlockInstructionsEquivalence.java b/src/main/java/com/android/tools/r8/ir/optimize/BasicBlockInstructionsEquivalence.java
index 5373a30..b57fd9b 100644
--- a/src/main/java/com/android/tools/r8/ir/optimize/BasicBlockInstructionsEquivalence.java
+++ b/src/main/java/com/android/tools/r8/ir/optimize/BasicBlockInstructionsEquivalence.java
@@ -12,6 +12,7 @@
import com.android.tools.r8.ir.regalloc.RegisterAllocator;
import com.google.common.base.Equivalence;
import java.util.Arrays;
+import java.util.Iterator;
import java.util.List;
class BasicBlockInstructionsEquivalence extends Equivalence<BasicBlock> {
@@ -34,9 +35,11 @@
if (instructions0.size() != instructions1.size()) {
return false;
}
- for (int i = 0; i < instructions0.size(); i++) {
- Instruction i0 = instructions0.get(i);
- Instruction i1 = instructions1.get(i);
+ Iterator<Instruction> it0 = instructions0.iterator();
+ Iterator<Instruction> it1 = instructions1.iterator();
+ while (it0.hasNext()) {
+ Instruction i0 = it0.next();
+ Instruction i1 = it1.next();
if (!i0.identicalAfterRegisterAllocation(i1, allocator, conversionOptions)) {
return false;
}
@@ -92,8 +95,11 @@
private int computeHash(BasicBlock basicBlock) {
List<Instruction> instructions = basicBlock.getInstructions();
int hash = instructions.size();
- for (int i = 0; i < instructions.size() && i < MAX_HASH_INSTRUCTIONS; i++) {
- Instruction instruction = instructions.get(i);
+ int i = 0;
+ for (Instruction instruction : instructions) {
+ if (++i > MAX_HASH_INSTRUCTIONS) {
+ break;
+ }
int hashPart = 0;
if (instruction.outValue() != null && instruction.outValue().needsRegister()) {
hashPart += allocator.getRegisterForValue(instruction.outValue(), instruction.getNumber());
