Enable optimization of functions with generic switches.

test/mjsunit/switch-opt.js

-// Copyright 2011 the V8 project authors. All rights reserved.
+// Copyright 2013 the V8 project authors. All rights reserved.
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 // modification, are permitted provided that the following conditions are
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 // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 
 // Flags: --allow-natives-syntax
 
-function f(x) {
-  var ret = -1;
-  switch(x){
+var result = [];
+
+function branch(b) {
+  if (b == "deopt") {
+    %DeoptimizeFunction(f);
+    return "c";
+  }
+
+  return b ? "a" : "b";
+}
+

[titzer, 2013/12/10 14:27:09]

I would like to see several more tests for this optimization, as there seem to
be many things that can go wrong. E.g. this test doesn't even have any
fallthrough between blocks.

I would have more confidence if I saw ~10 or more different switch statements in
this test.

+function f(label, b1, b2) {
+  switch (label) {
+    case "string":
+      result.push(1);
+      break;
+    case branch(b1) + branch(b2):
+      result.push(2);
+      break;
+    case 10:
+      result.push(3);
+      break;
     default:
-    case 0:
-      ret = 0;
+      branch(b1);
+      result.push(4);
       break;
-    case 1:
-      ret = 1;
-      break;
-    case 2:
-      ret = 2;
-      break;
-    case 3:
-      ret = 3;
-      break;
-    case 4:
-      ret = 4;
+    case 30:
+      result.push(5);
       break;
   }
-  return ret;
-};
+}
 
-for (var i = 0; i < 3; i++) assertEquals(i, f(i));
+function assertResult(r, label, b1, b2) {
+  f(label, b1, b2);
+  assertEquals(result, r);
+  result = [];
+}
 
+// Warmup.
+assertResult([2], "aa", true, true);
+assertResult([2], "ab", true, false);
+assertResult([2], "ba", false, true);
+assertResult([2], "bb", false, false);
+assertResult([4], "other");
+assertResult([5], 30);
+%OptimizeFunctionOnNextCall(f);
+// Test regular behavior.
+assertResult([2], "aa", true, true);
+assertResult([1], "string");
+assertResult([4], "other");
+assertResult([5], 30);
+
+// Test deopt at the beginning of the case label evaluation.
+assertResult([2], "ca", "deopt", true);
+%OptimizeFunctionOnNextCall(f);
+assertResult([4], "ca", "deopt", false);
 %OptimizeFunctionOnNextCall(f);
 
-assertEquals(0, f(0));
-assertEquals(1, f(1));
+// Test deopt in the middle of the case label evaluation.
+assertResult([2], "ac", true, "deopt");
+%OptimizeFunctionOnNextCall(f);
+assertResult([4], "ac", false, "deopt");