Unroll more StringDictionary lookup probes both for positive and negative dictionary lookups.

src/ia32/ic-ia32.cc

Index: src/ia32/ic-ia32.cc
diff --git a/src/ia32/ic-ia32.cc b/src/ia32/ic-ia32.cc
index 4106f0108903bde9f0cb9cef50f06bbb671ee3c2..2cee8b11696afe6039cdbd82cf5fdf4993e4b372 100644
--- a/src/ia32/ic-ia32.cc
+++ b/src/ia32/ic-ia32.cc
@@ -140,14 +140,26 @@ static void GenerateStringDictionaryProbes(MacroAssembler* masm,
     __ lea(r0, Operand(r0, r0, times_2, 0));  // r0 = r0 * 3
 
     // Check if the key is identical to the name.
-    __ cmp(name, Operand(elements, r0, times_4,
+    __ cmp(name, Operand(elements,
+                         r0,
+                         times_4,
                          kElementsStartOffset - kHeapObjectTag));
-    if (i != kProbes - 1) {
-      __ j(equal, done, taken);
-    } else {
-      __ j(not_equal, miss, not_taken);
-    }
+    __ j(equal, done, taken);
   }
+
+  StringDictionaryLookupStub stub(elements,
+                                  r1,
+                                  r0,
+                                  StringDictionaryLookupStub::POSITIVE_LOOKUP);
+  __ push(name);
+  __ mov(r0, FieldOperand(name, String::kHashFieldOffset));
+  __ shr(r0, String::kHashShift);
+  __ push(r0);
+  __ CallStub(&stub);
+
+  __ test(r1, Operand(r1));
+  __ j(zero, miss);
+  __ jmp(done);
 }