Tiny improvements on fast element conversion loops in ia32 and x64.

src/x64/codegen-x64.cc

 // Copyright 2011 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 225 matching lines @@
                       kDontSaveFPRegs,
                       EMIT_REMEMBERED_SET,
                       OMIT_SMI_CHECK);
   // Set backing store's length.
   __ Integer32ToSmi(r11, r9);
   __ movq(FieldOperand(r14, FixedDoubleArray::kLengthOffset), r11);
   __ jmp(&allocated);
 
   // Conversion loop.
   __ bind(&loop);
-  __ decq(r9);
   __ movq(rbx,
           FieldOperand(r8, r9, times_8, FixedArray::kHeaderSize));
   // r9 : current element's index
   // rbx: current element (smi-tagged)
   __ JumpIfNotSmi(rbx, &convert_hole);
   __ SmiToInteger32(rbx, rbx);
   __ cvtlsi2sd(xmm0, rbx);
   __ movsd(FieldOperand(r14, r9, times_8, FixedDoubleArray::kHeaderSize),
            xmm0);
   __ jmp(&entry);
   __ bind(&convert_hole);
   __ movq(FieldOperand(r14, r9, times_8, FixedDoubleArray::kHeaderSize), r15);
   __ bind(&entry);
-  __ testq(r9, r9);
-  __ j(not_zero, &loop);
+  __ decq(r9);
+  __ j(not_sign, &loop);
 }
 
 
 void ElementsTransitionGenerator::GenerateDoubleToObject(
     MacroAssembler* masm, Label* fail) {
   // ----------- S t a t e -------------
   //  -- rax    : value
   //  -- rbx    : target map
   //  -- rcx    : key
   //  -- rdx    : receiver
@@ skipping 22 matching lines @@
   __ jmp(&entry);
 
   // Call into runtime if GC is required.
   __ bind(&gc_required);
   __ pop(rax);
   __ movq(rsi, Operand(rbp, StandardFrameConstants::kContextOffset));
   __ jmp(fail);
 
   // Box doubles into heap numbers.
   __ bind(&loop);
-  __ decq(r9);
   __ movq(r14, FieldOperand(r8,
                             r9,
                             times_pointer_size,
                             FixedDoubleArray::kHeaderSize));
   // r9 : current element's index
   // r14: current element
   __ cmpq(r14, rsi);
   __ j(equal, &convert_hole);
 
   // Non-hole double, copy value into a heap number.
@@ skipping 16 matching lines @@
 
   // Replace the-hole NaN with the-hole pointer.
   __ bind(&convert_hole);
   __ movq(FieldOperand(r11,
                        r9,
                        times_pointer_size,
                        FixedArray::kHeaderSize),
           rdi);
 
   __ bind(&entry);
-  __ testq(r9, r9);
-  __ j(not_zero, &loop);
+  __ decq(r9);
+  __ j(not_sign, &loop);
 
   // Set transitioned map.
   __ movq(FieldOperand(rdx, HeapObject::kMapOffset), rbx);
   __ RecordWriteField(rdx,
                       HeapObject::kMapOffset,
                       rbx,
                       rdi,
                       kDontSaveFPRegs,
                       EMIT_REMEMBERED_SET,
                       OMIT_SMI_CHECK);
   // Replace receiver's backing store with newly created and filled FixedArray.
   __ movq(FieldOperand(rdx, JSObject::kElementsOffset), r11);
   __ RecordWriteField(rdx,
                       JSObject::kElementsOffset,
                       r11,
                       r15,
                       kDontSaveFPRegs,
                       EMIT_REMEMBERED_SET,
                       OMIT_SMI_CHECK);
   __ pop(rax);
   __ movq(rsi, Operand(rbp, StandardFrameConstants::kContextOffset));
 }
 
 #undef __
 
 } }  // namespace v8::internal
 
 #endif  // V8_TARGET_ARCH_X64