Take all uses into account to clear int32 truncation.

test/mjsunit/regress/regress-int32-truncation.js

Index: test/mjsunit/regress/regress-int32-truncation.js
diff --git a/test/mjsunit/regress/regress-2489.js b/test/mjsunit/regress/regress-int32-truncation.js
similarity index 81%
copy from test/mjsunit/regress/regress-2489.js
copy to test/mjsunit/regress/regress-int32-truncation.js
index 882c4f794a88e24d1d64e86a466b27c39f51e625..dec4ac1195a6c4928d84eac8cc8dc9496bf66600 100644
--- a/test/mjsunit/regress/regress-2489.js
+++ b/test/mjsunit/regress/regress-int32-truncation.js
@@ -27,24 +27,35 @@
 
 // Flags: --allow-natives-syntax
 
-"use strict";
-
-function f(a, b) {
-  return g("c", "d");
+function f(i, b) {
+  var a = 0;
+  if (b) {
+    var c = 1 << i;
+    a = c + c;
+  }
+  var x = a >> 3;
+  return a;
 }
 
-function g(a, b) {
-  g.constructor.apply(this, arguments);
-}
+f(1, false);
+f(1, true);
+%OptimizeFunctionOnNextCall(f);
+assertEquals((1 << 30) * 2, f(30, true));
 
-g.constructor = function(a, b) {
-  assertEquals("c", a);
-  assertEquals("d", b);
+
+var global = 1;
+
+function f2(b) {
+  var a = 0;
+  if (b) {
+    a = global;
+  }
+  var x = a >> 3;
+  return a;
 }
 
-f("a", "b");
-f("a", "b");
-%OptimizeFunctionOnNextCall(f);
-f("a", "b");
-g.x = "deopt";
-f("a", "b");
+f2(false);
+f2(true);
+%OptimizeFunctionOnNextCall(f2);
+global = 2.5;
+assertEquals(global, f2(true));