Fix a bug in Div when all uses are truncating

test/mjsunit/shift-for-integer-div.js

-// Copyright 2012 the V8 project authors. All rights reserved.
+// Copyright 2013 the V8 project authors. All rights reserved.

[Jakob Kummerow, 2013/08/20 13:51:23]

nit: we don't update copyright years anymore.

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+// Flags: --allow-natives-syntax
+
 function divp4(x) {
   return x / 4;
 }
 
-for (var i = 0; i < 10000; i+=4) {
-  assertEquals(i >> 2, divp4(i));
-}
+divp4(8);
+divp4(8);
+%OptimizeFunctionOnNextCall(divp4);
+assertEquals(2, divp4(8));
+assertEquals(0.5, divp4(2));
 
-assertEquals(0.5, divp4(2));
 
 function divn4(x) {
   return x / (-4);
 }
 
-for (var i = 0; i < 10000; i+=4) {
-  assertEquals(-(i >> 2), divn4(i));
-}
-
+divn4(8);
+divn4(8);
+%OptimizeFunctionOnNextCall(divn4);
+assertEquals(-2, divn4(8));
+// Check for (0 / -x)
 assertEquals(-0, divn4(0));
 
 
+// Check for (kMinInt / -1)
 function divn1(x) {
   return x / (-1);
 }
 
-for (var i = 0; i < 10000; i++) {
-  assertEquals(-i, divn1(i));
+var two_31 = 1 << 31;
+divn1(2);
+divn1(2);
+%OptimizeFunctionOnNextCall(divn1);
+assertEquals(-2, divn1(2));
+assertEquals(two_31, divn1(-two_31));
+
+
+//Check for truncating to int32 case
+function divp4t(x) {
+  return (x / 4) | 0;
 }
 
-var min_int = -(0x7FFFFFFF)-1;
-assertEquals(-min_int, divn1(min_int));
+divp4t(8);
+divp4t(8);
+%OptimizeFunctionOnNextCall(divp4t);
+assertEquals(-1, divp4t(-5));
+assertEquals(1, divp4t(5));
+assertOptimized(divp4t);
 
+function divn4t(x) {
+  return (x / -4) | 0;
+}
+
+divn4t(8);
+divn4t(8);
+%OptimizeFunctionOnNextCall(divn4t);
+assertEquals(1, divn4t(-5));
+assertEquals(-1, divn4t(5));
+assertOptimized(divn4t);