Reland "Add DoubleTestOp instruction"

runtime/vm/intrinsifier_arm64.cc

 // Copyright (c) 2014, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #include "vm/globals.h"  // Needed here to get TARGET_ARCH_ARM64.
 #if defined(TARGET_ARCH_ARM64)
 
 #include "vm/intrinsifier.h"
 
 #include "vm/assembler.h"
@@ skipping 1489 matching lines @@
   const Class& double_class = Class::Handle(
       Isolate::Current()->object_store()->double_class());
   __ TryAllocate(double_class, &fall_through, R0, R1);
   __ StoreDFieldToOffset(V0, R0, Double::value_offset());
   __ ret();
   __ Bind(&fall_through);
 }
 
 
 void Intrinsifier::Double_getIsNaN(Assembler* assembler) {
-  Label is_true;
   __ ldr(R0, Address(SP, 0 * kWordSize));
   __ LoadDFieldFromOffset(V0, R0, Double::value_offset());
   __ fcmpd(V0, V0);
   __ LoadObject(TMP, Bool::False());
   __ LoadObject(R0, Bool::True());
   __ csel(R0, TMP, R0, VC);
   __ ret();
 }
 
 
+void Intrinsifier::Double_getIsInfinite(Assembler* assembler) {
+  __ ldr(R0, Address(SP, 0 * kWordSize));
+  __ LoadFieldFromOffset(R0, R0, Double::value_offset());
+  // Mask off the sign.
+  __ AndImmediate(R0, R0, 0x7FFFFFFFFFFFFFFFLL);
+  // Compare with +infinity.
+  __ CompareImmediate(R0, 0x7FF0000000000000LL);
+  __ LoadObject(R0, Bool::False());
+  __ LoadObject(TMP, Bool::True());
+  __ csel(R0, TMP, R0, EQ);
+  __ ret();
+}
+
+
 void Intrinsifier::Double_getIsNegative(Assembler* assembler) {
   const Register false_reg = R0;
   const Register true_reg = R2;
   Label is_false, is_true, is_zero;
 
   __ ldr(R0, Address(SP, 0 * kWordSize));
   __ LoadDFieldFromOffset(V0, R0, Double::value_offset());
   __ fcmpdz(V0);
   __ LoadObject(true_reg, Bool::True());
   __ LoadObject(false_reg, Bool::False());
@@ skipping 681 matching lines @@
   __ cmp(R0, Operand(0));
   __ LoadObject(R0, Bool::False());
   __ LoadObject(TMP, Bool::True());
   __ csel(R0, TMP, R0, NE);
   __ ret();
 }
 
 }  // namespace dart
 
 #endif  // defined TARGET_ARCH_ARM64