Ported ia32 optimization of revision 3487 to x64.

src/x64/codegen-x64.cc

 // Copyright 2010 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 1203 matching lines @@
 
     // Duplicate the switch value.
     frame_->Dup();
 
     // Compile the label expression.
     Load(clause->label());
 
     // Compare and branch to the body if true or the next test if
     // false.  Prefer the next test as a fall through.
     ControlDestination dest(clause->body_target(), &next_test, false);
-    Comparison(equal, true, &dest);
+    Comparison(node, equal, true, &dest);
 
     // If the comparison fell through to the true target, jump to the
     // actual body.
     if (dest.true_was_fall_through()) {
       clause->body_target()->Unuse();
       clause->body_target()->Jump();
     }
   }
 
   // If there was control flow to a next test from the last one
@@ skipping 2343 matching lines @@
       __ testq(answer.reg(), answer.reg());
       answer.Unuse();
       destination()->Split(zero);
       return;
     }
     default:
       UNREACHABLE();
   }
   Load(left);
   Load(right);
-  Comparison(cc, strict, destination());
+  Comparison(node, cc, strict, destination());
 }
 
 
 void CodeGenerator::VisitThisFunction(ThisFunction* node) {
   frame_->PushFunction();
 }
 
 
 void CodeGenerator::GenerateArgumentsAccess(ZoneList<Expression*>* args) {
   ASSERT(args->length() == 1);
@@ skipping 1261 matching lines @@
     // For a variable that rewrites to a slot, we signal it is the immediate
     // subexpression of a typeof.
     LoadFromSlotCheckForArguments(variable->slot(), INSIDE_TYPEOF);
   } else {
     // Anything else can be handled normally.
     Load(expr);
   }
 }
 
 
-void CodeGenerator::Comparison(Condition cc,
+void CodeGenerator::Comparison(AstNode* node,
+                               Condition cc,
                                bool strict,
                                ControlDestination* dest) {
   // Strict only makes sense for equality comparisons.
   ASSERT(!strict || cc == equal);
 
   Result left_side;
   Result right_side;
   // Implement '>' and '<=' by reversal to obtain ECMA-262 conversion order.
   if (cc == greater || cc == less_equal) {
     cc = ReverseCondition(cc);
@@ skipping 26 matching lines @@
           break;
         case equal:
           dest->Goto(left_value == right_value);
           break;
         case greater_equal:
           dest->Goto(left_value >= right_value);
           break;
         default:
           UNREACHABLE();
       }
-    } else {  // Only one side is a constant Smi.
+    } else {
+      // Only one side is a constant Smi.
       // If left side is a constant Smi, reverse the operands.
       // Since one side is a constant Smi, conversion order does not matter.
       if (left_side_constant_smi) {
         Result temp = left_side;
         left_side = right_side;
         right_side = temp;
         cc = ReverseCondition(cc);
         // This may reintroduce greater or less_equal as the value of cc.
         // CompareStub and the inline code both support all values of cc.
       }
       // Implement comparison against a constant Smi, inlining the case
       // where both sides are Smis.
       left_side.ToRegister();
+      Register left_reg = left_side.reg();
+      Handle<Object> right_val = right_side.handle();
 
       // Here we split control flow to the stub call and inlined cases
       // before finally splitting it to the control destination.  We use
       // a jump target and branching to duplicate the virtual frame at
       // the first split.  We manually handle the off-frame references
       // by reconstituting them on the non-fall-through path.
       JumpTarget is_smi;
-      Register left_reg = left_side.reg();
-      Handle<Object> right_val = right_side.handle();
 
       Condition left_is_smi = masm_->CheckSmi(left_side.reg());
       is_smi.Branch(left_is_smi);
 
+      bool is_for_loop_compare = (node->AsCompareOperation() != NULL)
+          && node->AsCompareOperation()->is_for_loop_condition();
+      if (&& right_val->IsSmi()) {

[Søren Thygesen Gjesse, 2010/02/09 12:24:01]

is_for_loop_compare missing before &&?

+        // Right side is a constant smi and left side has been checked
+        // not to be a smi.
+        JumpTarget not_number;
+        __ Cmp(FieldOperand(left_reg, HeapObject::kMapOffset),
+               Factory::heap_number_map());
+        not_number.Branch(not_equal, &left_side);
+        __ movsd(xmm1,
+                 FieldOperand(left_reg, HeapNumber::kValueOffset));
+        int value = Smi::cast(*right_val)->value();
+        if (value == 0) {
+          __ xorpd(xmm0, xmm0);
+        } else {
+          Result temp = allocator()->Allocate();
+          __ movl(temp.reg(), Immediate(value));
+          __ cvtlsi2sd(xmm0, temp.reg());
+          temp.Unuse();
+        }
+        __ ucomisd(xmm1, xmm0);
+        // Jump to builtin for NaN.
+        not_number.Branch(parity_even, &left_side);
+        left_side.Unuse();
+        Condition double_cc = cc;
+        switch (cc) {
+          case less:          double_cc = below;       break;
+          case equal:         double_cc = equal;       break;
+          case less_equal:    double_cc = below_equal; break;
+          case greater:       double_cc = above;       break;
+          case greater_equal: double_cc = above_equal; break;
+          default: UNREACHABLE();
+        }
+        dest->true_target()->Branch(double_cc);
+        dest->false_target()->Jump();
+        not_number.Bind(&left_side);
+      }
+
       // Setup and call the compare stub.
       CompareStub stub(cc, strict);
       Result result = frame_->CallStub(&stub, &left_side, &right_side);
       result.ToRegister();
       __ testq(result.reg(), result.reg());
       result.Unuse();
       dest->true_target()->Branch(cc);
       dest->false_target()->Jump();
 
       is_smi.Bind();
@@ skipping 4236 matching lines @@
   // Call the function from C++.
   return FUNCTION_CAST<ModuloFunction>(buffer);
 }
 
 #endif
 
 
 #undef __
 
 } }  // namespace v8::internal