Add some test cases with dead loops.

test/mjsunit/compiler/dead-loops.js

Index: test/mjsunit/compiler/dead-loops.js
diff --git a/test/mjsunit/regress/regress-seqstrsetchar-ex3.js b/test/mjsunit/compiler/dead-loops.js
similarity index 59%
copy from test/mjsunit/regress/regress-seqstrsetchar-ex3.js
copy to test/mjsunit/compiler/dead-loops.js
index 43d2b083526cbf88da567896c1fd9207b587dd6d..2301b129dd7c435c17ec25b80caded4f088caa1a 100644
--- a/test/mjsunit/regress/regress-seqstrsetchar-ex3.js
+++ b/test/mjsunit/compiler/dead-loops.js
@@ -27,18 +27,61 @@
 
 // Flags: --allow-natives-syntax
 
-function test() {
-  var string = %NewString(10, true);
+// Presents opportunities for dead loop removal.
+
+function loop1() {
+  while (false) ;  // doesn't even loop.
+}
+
+function loop2() {
+  var i = 0;
+  while (i++ < 10) ;  // nothing in the body.
+}
+
+function loop3() {
+  for (var i = 0; i < 10; i++) ;  // nothing in the body.
+}
+
+function loop4() {
+  var a = 0;
+  for (var i = 0; i < 10; i++) a++;  // {a} is dead after the loop.
+}
+
+function loop5() {
+  var a = new Int32Array(4), sum = 0;
+  for (var i = 0; i < a.length; i++) {
+    // Involves only reads on typed arrays, and {i} doesn't overflow.
+    sum += a[i];
+  }
+}
+
+function loop6() {
+  var a = new Array(4), sum = 0;
+  for (var i = 0; i < a.length; i++) {
+    // Involves only in-bounds read on the array {a}.
+    // Have to prove that {a} doesn't have getters...?
+    sum += a[i];
+  }
+}
+
+function loop7() {
   for (var i = 0; i < 10; i++) {
-    %_OneByteSeqStringSetChar(string, i, 65);
-    %_OneByteSeqStringSetChar(string, i, 66);
+    new Object();  // Have to prove the allocation doesn't escape.
   }
+}
+
+function loop8() {
   for (var i = 0; i < 10; i++) {
-    assertEquals("B", string[i]);
+    var x = {};  // Have to prove the allocation doesn't escape.
   }
 }
 
-test();
-test();
-%OptimizeFunctionOnNextCall(test);
-test();
+var loops = [loop1, loop2, loop3, loop4, loop5, loop6, loop7, loop8];
+
+for (var i = 0; i < loops.length; i++) {
+  var f = loops[i];
+  f();
+  f();
+  %OptimizeFunctionOnNextCall(f);
+  f();
+}