From 2d5f6a81c2df5f04e712b23359ca696de2a3c8f1 Mon Sep 17 00:00:00 2001
From: Alexey Andreev <Alexey.Andreev@jetbrains.com>
Date: Sun, 7 May 2017 22:18:10 +0300
Subject: [PATCH] Improve peformance of Long.hashCode

---
 .../org/teavm/classlib/java/lang/TLong.java   |  2 +-
 .../rendering/StatementRenderer.java          | 35 +++++++++++++++++--
 .../teavm/classlib/java/lang/LongTest.java    |  8 +++++
 3 files changed, 42 insertions(+), 3 deletions(-)

diff --git a/classlib/src/main/java/org/teavm/classlib/java/lang/TLong.java b/classlib/src/main/java/org/teavm/classlib/java/lang/TLong.java
index a48dc605c..c40ab282a 100644
--- a/classlib/src/main/java/org/teavm/classlib/java/lang/TLong.java
+++ b/classlib/src/main/java/org/teavm/classlib/java/lang/TLong.java
@@ -198,7 +198,7 @@ public class TLong extends TNumber implements TComparable<TLong> {
     }
 
     private static int hashCode(long value) {
-        return (int) (value ^ (value >>> 32));
+        return (int) value ^ (int) (value >>> 32);
     }
 
     @Override
diff --git a/core/src/main/java/org/teavm/backend/javascript/rendering/StatementRenderer.java b/core/src/main/java/org/teavm/backend/javascript/rendering/StatementRenderer.java
index c8902b989..310c41588 100644
--- a/core/src/main/java/org/teavm/backend/javascript/rendering/StatementRenderer.java
+++ b/core/src/main/java/org/teavm/backend/javascript/rendering/StatementRenderer.java
@@ -881,8 +881,14 @@ public class StatementRenderer implements ExprVisitor, StatementVisitor {
                     switch (expr.getTarget()) {
                         case INT:
                             precedence = Precedence.MEMBER_ACCESS;
-                            expr.getValue().acceptVisitor(this);
-                            writer.append(".lo");
+                            Expr longShifted = extractLongRightShiftedBy32(expr.getValue());
+                            if (longShifted != null) {
+                                longShifted.acceptVisitor(this);
+                                writer.append(".hi");
+                            } else {
+                                expr.getValue().acceptVisitor(this);
+                                writer.append(".lo");
+                            }
                             break;
                         case FLOAT:
                         case DOUBLE:
@@ -927,6 +933,31 @@ public class StatementRenderer implements ExprVisitor, StatementVisitor {
         }
     }
 
+    private Expr extractLongRightShiftedBy32(Expr expr) {
+        if (!(expr instanceof BinaryExpr)) {
+            return null;
+        }
+
+        BinaryExpr binary = (BinaryExpr) expr;
+        if (binary.getOperation() != BinaryOperation.RIGHT_SHIFT
+                && binary.getOperation() != BinaryOperation.UNSIGNED_RIGHT_SHIFT) {
+            return null;
+        }
+        if (binary.getType() != OperationType.LONG) {
+            return null;
+        }
+        if (!(binary.getSecondOperand() instanceof ConstantExpr)) {
+            return null;
+        }
+
+        Object rightConstant = ((ConstantExpr) binary.getSecondOperand()).getValue();
+        if (rightConstant.equals(32) || rightConstant.equals(32L)) {
+            return binary.getFirstOperand();
+        }
+
+        return null;
+    }
+
     @Override
     public void visit(ConditionalExpr expr) {
         try {
diff --git a/tests/src/test/java/org/teavm/classlib/java/lang/LongTest.java b/tests/src/test/java/org/teavm/classlib/java/lang/LongTest.java
index 1eee9d544..3cf4573bb 100644
--- a/tests/src/test/java/org/teavm/classlib/java/lang/LongTest.java
+++ b/tests/src/test/java/org/teavm/classlib/java/lang/LongTest.java
@@ -15,9 +15,11 @@
  */
 package org.teavm.classlib.java.lang;
 
+import static org.junit.Assert.assertEquals;
 import static org.junit.Assert.assertTrue;
 import org.junit.Test;
 import org.junit.runner.RunWith;
+import org.teavm.junit.SkipJVM;
 import org.teavm.junit.TeaVMTestRunner;
 
 @RunWith(TeaVMTestRunner.class)
@@ -30,4 +32,10 @@ public class LongTest {
         assertTrue(Long.compare(Long.MAX_VALUE, Long.MIN_VALUE) > 0);
         assertTrue(Long.compare(Long.MIN_VALUE, Long.MAX_VALUE) < 0);
     }
+
+    @Test
+    @SkipJVM
+    public void calculatesHashCode() {
+        assertEquals(23 ^ 42, Long.hashCode((23L << 32) | 42));
+    }
 }