X64: Make the ToBoolean inline code do even less if the value is known to be a smi.

Review URL: http://codereview.chromium.org/2834028

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@4978 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

src/regexp.js

@@ -296,14 +296,14 @@ function RegExpTest(string) {
     return cache.answer;
   }
 
-  // Remove irrelevant preceeding '.*' in a test regexp. The expression  
-  // checks whether this.source starts with '.*' and that the third 
+  // Remove irrelevant preceeding '.*' in a test regexp. The expression
+  // checks whether this.source starts with '.*' and that the third
   // char is not a '?'
   if (%_StringCharCodeAt(this.source,0) == 46 && // '.'
-      %_StringCharCodeAt(this.source,1) == 42 && // '*' 
-      %_StringCharCodeAt(this.source,2) != 63) { // '?' 
+      %_StringCharCodeAt(this.source,1) == 42 && // '*'
+      %_StringCharCodeAt(this.source,2) != 63) { // '?'
     if (!%_ObjectEquals(regexp_key, this)) {
-      regexp_key = this; 
+      regexp_key = this;
       regexp_val = new $RegExp(this.source.substring(2, this.source.length),
                                (this.global ? 'g' : '')
                                + (this.ignoreCase ? 'i' : '')
@@ -311,7 +311,7 @@ function RegExpTest(string) {
     }
     if (!regexp_val.test(s)) return false;
   }
-  
+
   var length = s.length;
   var i = this.global ? TO_INTEGER(lastIndex) : 0;
 

src/x64/codegen-x64.cc

@@ -5342,13 +5342,18 @@ void CodeGenerator::ToBoolean(ControlDestination* dest) {
     }
     // Smi => false iff zero.
     __ SmiCompare(value.reg(), Smi::FromInt(0));
-    dest->false_target()->Branch(equal);
-    Condition is_smi = masm_->CheckSmi(value.reg());
-    dest->true_target()->Branch(is_smi);
-    __ xorpd(xmm0, xmm0);
-    __ ucomisd(xmm0, FieldOperand(value.reg(), HeapNumber::kValueOffset));
-    value.Unuse();
-    dest->Split(not_zero);
+    if (value.is_smi()) {
+      value.Unuse();
+      dest->Split(not_zero);
+    } else {
+      dest->false_target()->Branch(equal);
+      Condition is_smi = masm_->CheckSmi(value.reg());
+      dest->true_target()->Branch(is_smi);
+      __ xorpd(xmm0, xmm0);
+      __ ucomisd(xmm0, FieldOperand(value.reg(), HeapNumber::kValueOffset));
+      value.Unuse();
+      dest->Split(not_zero);
+    }
   } else {
     // Fast case checks.
     // 'false' => false.