X64: Change some fpu operations to use XMM registers.

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 5318 matching lines @@
   if (value.is_number()) {
     // Fast case if TypeInfo indicates only numbers.
     if (FLAG_debug_code) {
       __ AbortIfNotNumber(value.reg());
     }
     // 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);
-    __ fldz();
-    __ fld_d(FieldOperand(value.reg(), HeapNumber::kValueOffset));
-    __ FCmp();
+    __ xorpd(xmm0, xmm0);
+    __ ucomisd(xmm0, FieldOperand(value.reg(), HeapNumber::kValueOffset));
     value.Unuse();
     dest->Split(not_zero);
   } else {
     // Fast case checks.
     // 'false' => false.
     __ CompareRoot(value.reg(), Heap::kFalseValueRootIndex);
     dest->false_target()->Branch(equal);
 
     // 'true' => true.
     __ CompareRoot(value.reg(), Heap::kTrueValueRootIndex);
@@ skipping 2641 matching lines @@
 
   // String value => false iff empty.
   __ cmpq(rcx, Immediate(FIRST_NONSTRING_TYPE));
   __ j(above_equal, &not_string);
   __ movq(rdx, FieldOperand(rax, String::kLengthOffset));
   __ SmiTest(rdx);
   __ j(zero, &false_result);
   __ jmp(&true_result);
 
   __ bind(&not_string);
-  // HeapNumber => false iff +0, -0, or NaN.
-  // These three cases set C3 when compared to zero in the FPU.
   __ CompareRoot(rdx, Heap::kHeapNumberMapRootIndex);
   __ j(not_equal, &true_result);
-  __ fldz();  // Load zero onto fp stack
-  // Load heap-number double value onto fp stack
-  __ fld_d(FieldOperand(rax, HeapNumber::kValueOffset));
-  __ FCmp();
+  // HeapNumber => false iff +0, -0, or NaN.
+  // These three cases set the zero flag when compared to zero using ucomisd.
+  __ xorpd(xmm0, xmm0);
+  __ ucomisd(xmm0, FieldOperand(rax, HeapNumber::kValueOffset));
   __ j(zero, &false_result);
   // Fall through to |true_result|.
 
   // Return 1/0 for true/false in rax.
   __ bind(&true_result);
   __ movq(rax, Immediate(1));
   __ ret(1 * kPointerSize);
   __ bind(&false_result);
   __ xor_(rax, rax);
   __ ret(1 * kPointerSize);
@@ skipping 3873 matching lines @@
 }
 
 #endif
 
 
 #undef __
 
 } }  // namespace v8::internal
 
 #endif  // V8_TARGET_ARCH_X64