Inline floating point compare...

src/ia32/codegen-ia32.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 893 matching lines @@
   enum ArgLocation {
     ARGS_ON_STACK,
     ARGS_IN_REGISTERS
   };
 
   // Code pattern for loading a floating point value. Input value must
   // be either a smi or a heap number object (fp value). Requirements:
   // operand in register number. Returns operand as floating point number
   // on FPU stack.
   static void LoadFloatOperand(MacroAssembler* masm, Register number);
+
   // Code pattern for loading floating point values. Input values must
   // be either smi or heap number objects (fp values). Requirements:
   // operand_1 on TOS+1 or in edx, operand_2 on TOS+2 or in eax.
   // Returns operands as floating point numbers on FPU stack.
   static void LoadFloatOperands(MacroAssembler* masm,
                                 Register scratch,
                                 ArgLocation arg_location = ARGS_ON_STACK);
 
   // Similar to LoadFloatOperand but assumes that both operands are smis.
   // Expects operands in edx, eax.
   static void LoadFloatSmis(MacroAssembler* masm, Register scratch);
 
   // Test if operands are smi or number objects (fp). Requirements:
   // operand_1 in eax, operand_2 in edx; falls through on float
   // operands, jumps to the non_float label otherwise.
   static void CheckFloatOperands(MacroAssembler* masm,
                                  Label* non_float,
                                  Register scratch);
+
   // Takes the operands in edx and eax and loads them as integers in eax
   // and ecx.
   static void LoadAsIntegers(MacroAssembler* masm,
                              NumberInfo number_info,
                              bool use_sse3,
                              Label* operand_conversion_failure);
   static void LoadNumbersAsIntegers(MacroAssembler* masm,
                                     NumberInfo number_info,
                                     bool use_sse3,
                                     Label* operand_conversion_failure);
   static void LoadUnknownsAsIntegers(MacroAssembler* masm,
                                      bool use_sse3,
                                      Label* operand_conversion_failure);
 
   // Test if operands are smis or heap numbers and load them
   // into xmm0 and xmm1 if they are. Operands are in edx and eax.
   // Leaves operands unchanged.
   static void LoadSSE2Operands(MacroAssembler* masm);
+
   // Test if operands are numbers (smi or HeapNumber objects), and load
   // them into xmm0 and xmm1 if they are.  Jump to label not_numbers if
   // either operand is not a number.  Operands are in edx and eax.
   // Leaves operands unchanged.
   static void LoadSSE2Operands(MacroAssembler* masm, Label* not_numbers);
 
   // Similar to LoadSSE2Operands but assumes that both operands are smis.
   // Expects operands in edx, eax.
   static void LoadSSE2Smis(MacroAssembler* masm, Register scratch);
 };
@@ skipping 1394 matching lines @@
 
 static bool CouldBeNaN(const Result& result) {
   if (result.number_info().IsSmi()) return false;
   if (result.number_info().IsInteger32()) return false;
   if (!result.is_constant()) return true;
   if (!result.handle()->IsHeapNumber()) return false;
   return isnan(HeapNumber::cast(*result.handle())->value());
 }
 
 
+// Convert from signed to unsigned comparison to match the way EFLAGS are set
+// by FPU and XMM compare instructions.
+static Condition DoubleCondition(Condition cc) {
+  switch (cc) {
+    case less:          return below;
+    case equal:         return equal;
+    case less_equal:    return below_equal;
+    case greater:       return above;
+    case greater_equal: return above_equal;
+    default:            UNREACHABLE();
+  }
+  UNREACHABLE();
+  return equal;
+}
+
+
 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.
@@ skipping 50 matching lines @@
       }
     } 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.
+        // This may re-introduce 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
@@ skipping 28 matching lines @@
           } else {
             Result temp = allocator()->Allocate();
             __ mov(temp.reg(), Immediate(value));
             __ cvtsi2sd(xmm0, Operand(temp.reg()));
             temp.Unuse();
           }
           __ comisd(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->true_target()->Branch(DoubleCondition(cc));
           dest->false_target()->Jump();
           not_number.Bind(&left_side);
         }
 
         // Setup and call the compare stub.
         CompareStub stub(cc, strict, kCantBothBeNaN);
         Result result = frame_->CallStub(&stub, &left_side, &right_side);
         result.ToRegister();
         __ cmp(result.reg(), 0);
         result.Unuse();
@@ skipping 178 matching lines @@
         __ cmp(FieldOperand(left_side.reg(), String::kLengthOffset),
                Immediate(1));
         __ bind(&characters_were_different);
       }
       temp2.Unuse();
       left_side.Unuse();
       right_side.Unuse();
       dest->Split(cc);
     }
   } else {
-    // Neither side is a constant Smi or null.
-    // If either side is a non-smi constant, skip the smi check.
+    // Neither side is a constant Smi, constant 1-char string or constant null.
+    // If either side is a non-smi constant, or known to be a heap number skip
+    // the smi check.
     bool known_non_smi =
         (left_side.is_constant() && !left_side.handle()->IsSmi()) ||
-        (right_side.is_constant() && !right_side.handle()->IsSmi());
+        (right_side.is_constant() && !right_side.handle()->IsSmi()) ||
+        left_side.number_info().IsHeapNumber() ||
+        right_side.number_info().IsHeapNumber();
     NaNInformation nan_info =
         (CouldBeNaN(left_side) && CouldBeNaN(right_side)) ?
         kBothCouldBeNaN :
         kCantBothBeNaN;
+
+    // Inline number comparison handling any combination of smi's and heap
+    // numbers if:
+    //   code is in a loop
+    //   the compare operation is different from equal
+    //   compare is not a for-loop comparison
+    // The reason for excluding equal is that it will most likely be done
+    // with smi's (not heap numbers) and the code to comparing smi's is inlined
+    // separately. The same reason applies for for-loop comparison which will
+    // also most likely be smi comparisons.
+    bool is_for_loop_compare = (node->AsCompareOperation() != NULL)
+        && node->AsCompareOperation()->is_for_loop_condition();
+    bool inline_number_compare = loop_nesting() > 0
+                                 && cc != equal
+                                 && !is_for_loop_compare;
+
+    // Left and right needed in registers for the following code.
     left_side.ToRegister();
     right_side.ToRegister();
 
     if (known_non_smi) {
-      // When non-smi, call out to the compare stub.
-      CompareStub stub(cc, strict, nan_info);
+      // Inline the equality check if both operands can't be a NaN. If both
+      // objects are the same they are equal.
+      if (nan_info == kCantBothBeNaN && cc == equal) {

[Erik Corry, 2010/03/23 18:09:24]

This seems wrong.  If one side is a constant fp number then they can't both be
NaN, but you still have to check whether the other side is a number or a JS
object with an arbitrary ToNumber method with side effects.  If we insisted on
strict equality it might be OK.

[Søren Thygesen Gjesse, 2010/03/23 20:40:01]

This will only provide true when the objects are the same, but not false if they
are different. If they are not the same objects all the rest of the compare code
will perform all the rest of the checks.

+        __ cmp(left_side.reg(), Operand(right_side.reg()));
+        dest->true_target()->Branch(equal);
+      }
+
+      // Inline number comparison.
+      if (inline_number_compare) {
+        GenerateInlineNumberComparison(&left_side, &right_side, cc, dest);
+      }
+
+      // End of in-line compare, call out to the compare stub. Don't include
+      // number comparison in the stub if it was inlined.
+      CompareStub stub(cc, strict, nan_info, !inline_number_compare);
       Result answer = frame_->CallStub(&stub, &left_side, &right_side);
       if (cc == equal) {
         __ test(answer.reg(), Operand(answer.reg()));
       } else {
         __ cmp(answer.reg(), 0);
       }
       answer.Unuse();
       dest->Split(cc);
     } else {
       // 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();
       Register right_reg = right_side.reg();
 
+      // In-line check for comparing two smis.
       Result temp = allocator_->Allocate();
       ASSERT(temp.is_valid());
       __ mov(temp.reg(), left_side.reg());
       __ or_(temp.reg(), Operand(right_side.reg()));
       __ test(temp.reg(), Immediate(kSmiTagMask));
       temp.Unuse();
       is_smi.Branch(zero, taken);
-      // When non-smi, call out to the compare stub.
-      CompareStub stub(cc, strict, nan_info);
+
+      // Inline the equality check if both operands can't be a NaN. If both
+      // objects are the same they are equal.
+      if (nan_info == kCantBothBeNaN && cc == equal) {
+        __ cmp(left_side.reg(), Operand(right_side.reg()));
+        dest->true_target()->Branch(equal);
+      }
+
+      // Inline number comparison.
+      if (inline_number_compare) {
+        GenerateInlineNumberComparison(&left_side, &right_side, cc, dest);
+      }
+
+      // End of in-line compare, call out to the compare stub. Don't include
+      // number comparison in the stub if it was inlined.
+      CompareStub stub(cc, strict, nan_info, !inline_number_compare);
       Result answer = frame_->CallStub(&stub, &left_side, &right_side);
       if (cc == equal) {
         __ test(answer.reg(), Operand(answer.reg()));
       } else {
         __ cmp(answer.reg(), 0);
       }
       answer.Unuse();
       dest->true_target()->Branch(cc);
       dest->false_target()->Jump();
 
       is_smi.Bind();
       left_side = Result(left_reg);
       right_side = Result(right_reg);
       __ cmp(left_side.reg(), Operand(right_side.reg()));
       right_side.Unuse();
       left_side.Unuse();
       dest->Split(cc);
     }
   }
 }
 
 
+// Check that the comparison operand is a number. Jump to not_numbers jump
+// target passing the left and right result if the operand is not a number.
+static void CheckComparisonOperand(MacroAssembler* masm_,
+                                   Result* operand,
+                                   Result* left_side,
+                                   Result* right_side,
+                                   JumpTarget* not_numbers) {
+  // Perform check if operand is not known to be a number.
+  if (!operand->number_info().IsNumber()) {
+    Label done;
+    __ test(operand->reg(), Immediate(kSmiTagMask));
+    __ j(zero, &done);
+    __ cmp(FieldOperand(operand->reg(), HeapObject::kMapOffset),
+           Immediate(Factory::heap_number_map()));
+    not_numbers->Branch(not_equal, left_side, right_side, not_taken);
+    __ bind(&done);
+  }
+}
+
+
+// Load a comparison operand to the FPU stack. This assumes that the operand has
+// already been checked and is a number.
+static void LoadComparisonOperand(MacroAssembler* masm_,
+                                  Result* operand,
+                                  Result* left_side,
+                                  Result* right_side) {
+  Label done;
+  if (operand->number_info().IsHeapNumber()) {
+    // Operand is known to be a heap number, just load it.
+    __ fld_d(FieldOperand(operand->reg(), HeapNumber::kValueOffset));
+  } else if (operand->number_info().IsSmi()) {
+    // Operand is known to be a smi. Convert it to double and keep the original
+    // smi.
+    __ SmiUntag(operand->reg());
+    __ push(operand->reg());
+    __ fild_s(Operand(esp, 0));
+    __ pop(operand->reg());
+    __ SmiTag(operand->reg());
+  } else {
+    // Operand type not known, check for smi otherwise assume heap number.
+    Label smi;
+    __ test(operand->reg(), Immediate(kSmiTagMask));
+    __ j(zero, &smi);
+    __ fld_d(FieldOperand(operand->reg(), HeapNumber::kValueOffset));
+    __ jmp(&done);
+    __ bind(&smi);
+    __ SmiUntag(operand->reg());
+    __ push(operand->reg());
+    __ fild_s(Operand(esp, 0));
+    __ pop(operand->reg());
+    __ SmiTag(operand->reg());
+    __ jmp(&done);
+  }
+  __ bind(&done);
+}
+
+
+// Load a comparison operand into into a XMM register. Jump to not_numbers jump
+// target passing the left and right result if the operand is not a number.
+static void LoadComparisonOperandSSE2(MacroAssembler* masm_,
+                                      Result* operand,
+                                      XMMRegister reg,
+                                      Result* left_side,
+                                      Result* right_side,
+                                      JumpTarget* not_numbers) {
+  Label done;
+  if (operand->number_info().IsHeapNumber()) {
+    // Operand is known to be a heap number, just load it.
+    __ movdbl(reg, FieldOperand(operand->reg(), HeapNumber::kValueOffset));
+  } else if (operand->number_info().IsSmi()) {
+    // Operand is known to be a smi. Convert it to double and keep the original
+    // smi.
+    __ SmiUntag(operand->reg());
+    __ cvtsi2sd(reg, Operand(operand->reg()));
+    __ SmiTag(left_side->reg());
+  } else {
+    // Operand type not known, check for smi or heap number.
+    Label smi;
+    __ test(operand->reg(), Immediate(kSmiTagMask));
+    __ j(zero, &smi);
+    if (!operand->number_info().IsNumber()) {
+      __ cmp(FieldOperand(operand->reg(), HeapObject::kMapOffset),
+             Immediate(Factory::heap_number_map()));
+      not_numbers->Branch(not_equal, left_side, right_side, taken);
+    }
+    __ movdbl(reg, FieldOperand(operand->reg(), HeapNumber::kValueOffset));
+    __ jmp(&done);
+
+    __ bind(&smi);
+    // Comvert smi to float and keep the original smi.
+    __ SmiUntag(operand->reg());
+    __ cvtsi2sd(reg, Operand(operand->reg()));
+    __ SmiTag(operand->reg());
+    __ jmp(&done);
+  }
+  __ bind(&done);
+}
+
+
+void CodeGenerator::GenerateInlineNumberComparison(Result* left_side,
+                                                   Result* right_side,
+                                                   Condition cc,
+                                                   ControlDestination* dest) {
+  ASSERT(left_side->is_register());
+  ASSERT(right_side->is_register());
+
+  JumpTarget not_numbers;
+  if (CpuFeatures::IsSupported(SSE2)) {
+    CpuFeatures::Scope use_sse2(SSE2);
+
+    // Load left and right operand into registers xmm0 and xmm1 and compare.
+    LoadComparisonOperandSSE2(masm_, left_side, xmm0, left_side, right_side,
+                              &not_numbers);
+    LoadComparisonOperandSSE2(masm_, right_side, xmm1, left_side, right_side,
+                              &not_numbers);
+    __ comisd(xmm0, xmm1);
+  } else {
+    Label check_right, compare;
+
+    // Make sure that both comparison operands are numbers.
+    CheckComparisonOperand(masm_, left_side, left_side, right_side,
+                           &not_numbers);
+    CheckComparisonOperand(masm_, right_side, left_side, right_side,
+                           &not_numbers);
+
+    // Load right and left operand to FPU stack and compare.
+    LoadComparisonOperand(masm_, right_side, left_side, right_side);
+    LoadComparisonOperand(masm_, left_side, left_side, right_side);
+    __ FCmp();
+  }
+
+  // Bail out if a NaN is involved.
+  not_numbers.Branch(parity_even, left_side, right_side, not_taken);
+
+  // Split to destination targets based on comparison.
+  left_side->Unuse();
+  right_side->Unuse();
+  dest->true_target()->Branch(DoubleCondition(cc));
+  dest->false_target()->Jump();
+
+  not_numbers.Bind(left_side, right_side);
+}
+
+
 // Call the function just below TOS on the stack with the given
 // arguments. The receiver is the TOS.
 void CodeGenerator::CallWithArguments(ZoneList<Expression*>* args,
                                       CallFunctionFlags flags,
                                       int position) {
   // Push the arguments ("left-to-right") on the stack.
   int arg_count = args->length();
   for (int i = 0; i < arg_count; i++) {
     Load(args->at(i));
   }
@@ skipping 8049 matching lines @@
     }
     __ bind(&slow);
   }
 
   // Push arguments below the return address.
   __ pop(ecx);
   __ push(eax);
   __ push(edx);
   __ push(ecx);
 
-  // Inlined floating point compare.
-  // Call builtin if operands are not floating point or smi.
-  Label check_for_symbols;
-  Label unordered;
-  if (CpuFeatures::IsSupported(SSE2)) {
-    CpuFeatures::Scope use_sse2(SSE2);
-    CpuFeatures::Scope use_cmov(CMOV);
+  // Generate the number comparison code.
+  if (include_number_compare_) {
+    Label non_number_comparison;
+    Label unordered;
+    if (CpuFeatures::IsSupported(SSE2)) {
+      CpuFeatures::Scope use_sse2(SSE2);
+      CpuFeatures::Scope use_cmov(CMOV);
 
-    FloatingPointHelper::LoadSSE2Operands(masm, &check_for_symbols);
-    __ comisd(xmm0, xmm1);
+      FloatingPointHelper::LoadSSE2Operands(masm, &non_number_comparison);
+      __ comisd(xmm0, xmm1);
 
-    // Jump to builtin for NaN.
-    __ j(parity_even, &unordered, not_taken);
-    __ mov(eax, 0);  // equal
-    __ mov(ecx, Immediate(Smi::FromInt(1)));
-    __ cmov(above, eax, Operand(ecx));
-    __ mov(ecx, Immediate(Smi::FromInt(-1)));
-    __ cmov(below, eax, Operand(ecx));
-    __ ret(2 * kPointerSize);
-  } else {
-    FloatingPointHelper::CheckFloatOperands(masm, &check_for_symbols, ebx);
-    FloatingPointHelper::LoadFloatOperands(masm, ecx);
-    __ FCmp();
+      // Don't base result on EFLAGS when a NaN is involved.
+      __ j(parity_even, &unordered, not_taken);
+      // Return a result of -1, 0, or 1, based on EFLAGS.
+      __ mov(eax, 0);  // equal
+      __ mov(ecx, Immediate(Smi::FromInt(1)));
+      __ cmov(above, eax, Operand(ecx));
+      __ mov(ecx, Immediate(Smi::FromInt(-1)));
+      __ cmov(below, eax, Operand(ecx));
+      __ ret(2 * kPointerSize);
+    } else {
+      FloatingPointHelper::CheckFloatOperands(
+          masm, &non_number_comparison, ebx);
+      FloatingPointHelper::LoadFloatOperands(masm, ecx);
+      __ FCmp();
 
-    // Jump to builtin for NaN.
-    __ j(parity_even, &unordered, not_taken);
+      // Don't base result on EFLAGS when a NaN is involved.
+      __ j(parity_even, &unordered, not_taken);
 
-    Label below_lbl, above_lbl;
-    // Return a result of -1, 0, or 1, to indicate result of comparison.
-    __ j(below, &below_lbl, not_taken);
-    __ j(above, &above_lbl, not_taken);
+      Label below_label, above_label;
+      // Return a result of -1, 0, or 1, based on EFLAGS. In all cases remove
+      // two arguments from the stack as they have been pushed in preparation
+      // of a possible runtime call.
+      __ j(below, &below_label, not_taken);
+      __ j(above, &above_label, not_taken);
 
-    __ xor_(eax, Operand(eax));  // equal
-    // Both arguments were pushed in case a runtime call was needed.
-    __ ret(2 * kPointerSize);
+      __ xor_(eax, Operand(eax));
+      __ ret(2 * kPointerSize);
 
-    __ bind(&below_lbl);
-    __ mov(eax, Immediate(Smi::FromInt(-1)));
-    __ ret(2 * kPointerSize);
+      __ bind(&below_label);
+      __ mov(eax, Immediate(Smi::FromInt(-1)));
+      __ ret(2 * kPointerSize);
 
-    __ bind(&above_lbl);
-    __ mov(eax, Immediate(Smi::FromInt(1)));
+      __ bind(&above_label);
+      __ mov(eax, Immediate(Smi::FromInt(1)));
+      __ ret(2 * kPointerSize);
+    }
+
+    // If one of the numbers was NaN, then the result is always false.
+    // The cc is never not-equal.
+    __ bind(&unordered);
+    ASSERT(cc_ != not_equal);
+    if (cc_ == less || cc_ == less_equal) {
+      __ mov(eax, Immediate(Smi::FromInt(1)));
+    } else {
+      __ mov(eax, Immediate(Smi::FromInt(-1)));
+    }
     __ ret(2 * kPointerSize);  // eax, edx were pushed
+
+    // The number comparison code did not provide a valid result.
+    __ bind(&non_number_comparison);
   }
-  // If one of the numbers was NaN, then the result is always false.
-  // The cc is never not-equal.
-  __ bind(&unordered);
-  ASSERT(cc_ != not_equal);
-  if (cc_ == less || cc_ == less_equal) {
-    __ mov(eax, Immediate(Smi::FromInt(1)));
-  } else {
-    __ mov(eax, Immediate(Smi::FromInt(-1)));
-  }
-  __ ret(2 * kPointerSize);  // eax, edx were pushed
 
   // Fast negative check for symbol-to-symbol equality.
-  __ bind(&check_for_symbols);
   Label check_for_strings;
   if (cc_ == equal) {
     BranchIfNonSymbol(masm, &check_for_strings, eax, ecx);
     BranchIfNonSymbol(masm, &check_for_strings, edx, ecx);
 
     // We've already checked for object identity, so if both operands
     // are symbols they aren't equal. Register eax already holds a
     // non-zero value, which indicates not equal, so just return.
     __ ret(2 * kPointerSize);
   }
@@ skipping 636 matching lines @@
     }
     default: return "CompareStub";
   }
 }
 
 
 int CompareStub::MinorKey() {
   // Encode the three parameters in a unique 16 bit value. To avoid duplicate
   // stubs the never NaN NaN condition is only taken into account if the
   // condition is equals.
-  ASSERT(static_cast<unsigned>(cc_) < (1 << 14));
+  ASSERT(static_cast<unsigned>(cc_) < (1 << 13));
   return ConditionField::encode(static_cast<unsigned>(cc_))
          | StrictField::encode(strict_)
-         | NeverNanNanField::encode(cc_ == equal ? never_nan_nan_ : false);
+         | NeverNanNanField::encode(cc_ == equal ? never_nan_nan_ : false)
+         | IncludeNumberCompareField::encode(include_number_compare_);
 }
 
 
 void StringAddStub::Generate(MacroAssembler* masm) {
   Label string_add_runtime;
 
   // Load the two arguments.
   __ mov(eax, Operand(esp, 2 * kPointerSize));  // First argument.
   __ mov(edx, Operand(esp, 1 * kPointerSize));  // Second argument.
 
@@ skipping 613 matching lines @@
 
 void StringCompareStub::GenerateCompareFlatAsciiStrings(MacroAssembler* masm,
                                                         Register left,
                                                         Register right,
                                                         Register scratch1,
                                                         Register scratch2,
                                                         Register scratch3) {
   Label result_not_equal;
   Label result_greater;
   Label compare_lengths;
+
+  __ IncrementCounter(&Counters::string_compare_native, 1);
+
   // Find minimum length.
   Label left_shorter;
   __ mov(scratch1, FieldOperand(left, String::kLengthOffset));
   __ mov(scratch3, scratch1);
   __ sub(scratch3, FieldOperand(right, String::kLengthOffset));
 
   Register length_delta = scratch3;
 
   __ j(less_equal, &left_shorter);
   // Right string is shorter. Change scratch1 to be length of right string.
@@ skipping 77 matching lines @@
   __ Set(eax, Immediate(Smi::FromInt(EQUAL)));
   __ IncrementCounter(&Counters::string_compare_native, 1);
   __ ret(2 * kPointerSize);
 
   __ bind(&not_same);
 
   // Check that both objects are sequential ascii strings.
   __ JumpIfNotBothSequentialAsciiStrings(edx, eax, ecx, ebx, &runtime);
 
   // Compare flat ascii strings.
-  __ IncrementCounter(&Counters::string_compare_native, 1);
   GenerateCompareFlatAsciiStrings(masm, edx, eax, ecx, ebx, edi);
 
   // Call the runtime; it returns -1 (less), 0 (equal), or 1 (greater)
   // tagged as a small integer.
   __ bind(&runtime);
   __ TailCallRuntime(Runtime::kStringCompare, 2, 1);
 }
 
 #undef __
 
 } }  // namespace v8::internal