Changeset 34171 in webkit for trunk/JavaScriptCore/VM/Machine.cpp

Timestamp:

May 28, 2008, 3:48:04 AM (17 years ago)

Author:

[email protected]

Message:

Reviewed by Maciej.

Based on a patch by Oliver Hunt.

​https://bugs.webkit.org/show_bug.cgi?id=19180
speed up SunSpider by optimizing immediate number cases

1.4% speedup on SunSpider.

• VM/Machine.cpp: (KJS::Machine::privateExecute):
• kjs/JSImmediate.h: (KJS::JSImmediate::incImmediateNumber): (KJS::JSImmediate::decImmediateNumber): Added fast paths for ++ and --.

(KJS::JSImmediate::canDoFastAdditiveOperations): Corrected a comment.

File:

• trunk/JavaScriptCore/VM/Machine.cpp (modified) (4 diffs)

trunk/JavaScriptCore/VM/Machine.cpp

@@ -1078 +1078 @@
         */
         int srcDst = (++vPC)->u.operand;
-        JSValue* result = jsNumber(r[srcDst].u.jsValue->toNumber(exec) + 1);
+        JSValue* v = r[srcDst].u.jsValue;
+        JSValue* result;
+        if (JSImmediate::canDoFastAdditiveOperations(v))
+            result = JSImmediate::incImmediateNumber(v);
+        else
+            result = jsNumber(v->toNumber(exec) + 1);
         VM_CHECK_EXCEPTION();
         r[srcDst].u.jsValue = result;
@@ -1092 +1097 @@
         */
         int srcDst = (++vPC)->u.operand;
-        JSValue* result = jsNumber(r[srcDst].u.jsValue->toNumber(exec) - 1);
+        JSValue* v = r[srcDst].u.jsValue;
+        JSValue* result;
+        if (JSImmediate::canDoFastAdditiveOperations(v))
+            result = JSImmediate::decImmediateNumber(v);
+        else
+            result = jsNumber(v->toNumber(exec) - 1);
         VM_CHECK_EXCEPTION();
         r[srcDst].u.jsValue = result;
@@ -1108 +1118 @@
         int dst = (++vPC)->u.operand;
         int srcDst = (++vPC)->u.operand;
-        JSValue* number = r[srcDst].u.jsValue->toJSNumber(exec);
+        JSValue* v = r[srcDst].u.jsValue;
+        JSValue* result;
+        JSValue* number;
+        if (JSImmediate::canDoFastAdditiveOperations(v)) {
+            number = v;
+            result = JSImmediate::incImmediateNumber(v);
+        } else {
+            number = r[srcDst].u.jsValue->toJSNumber(exec);
+            result = jsNumber(number->uncheckedGetNumber() + 1);
+        }
         VM_CHECK_EXCEPTION();
 
         r[dst].u.jsValue = number;
-        r[srcDst].u.jsValue = jsNumber(number->uncheckedGetNumber() + 1);
+        r[srcDst].u.jsValue = result;
 
         ++vPC;
@@ -1126 +1145 @@
         int dst = (++vPC)->u.operand;
         int srcDst = (++vPC)->u.operand;
-        JSValue* number = r[srcDst].u.jsValue->toJSNumber(exec);
+        JSValue* v = r[srcDst].u.jsValue;
+        JSValue* result;
+        JSValue* number;
+        if (JSImmediate::canDoFastAdditiveOperations(v)) {
+            number = v;
+            result = JSImmediate::decImmediateNumber(v);
+        } else {
+            number = r[srcDst].u.jsValue->toJSNumber(exec);
+            result = jsNumber(number->uncheckedGetNumber() - 1);
+        }
         VM_CHECK_EXCEPTION();
 
         r[dst].u.jsValue = number;
-        r[srcDst].u.jsValue = jsNumber(number->uncheckedGetNumber() - 1);
+        r[srcDst].u.jsValue = result;
 
         ++vPC;