A64: Introduce a DeoptimizeIfMinusZero() helper.

src/a64/macro-assembler-a64.h

Index: src/a64/macro-assembler-a64.h
diff --git a/src/a64/macro-assembler-a64.h b/src/a64/macro-assembler-a64.h
index 651be99a6fb6657ac7f55a2659e71a83cbbea7c1..59412f3a64935dd76b7a246e742376996e1ea2dd 100644
--- a/src/a64/macro-assembler-a64.h
+++ b/src/a64/macro-assembler-a64.h
@@ -900,6 +900,9 @@ class MacroAssembler : public Assembler {
                            Label* on_not_heap_number,
                            Register heap_number_map = NoReg);
 
+  // Sets the vs flag if the input is -0.0.
+  void TestForMinusZero(DoubleRegister input);
+
   // Jump to label if the input double register contains -0.0.
   void JumpIfMinusZero(DoubleRegister input, Label* on_negative_zero);
 
@@ -928,10 +931,12 @@ class MacroAssembler : public Assembler {
   // Try to convert a double to a signed 32-bit int.
   // This succeeds if the result compares equal to the input, so inputs of -0.0
   // are converted to 0 and handled as a success.
+  //
+  // On output the Z flag is set if the conversion was successful.
   void TryConvertDoubleToInt32(Register as_int,
                                FPRegister value,
                                FPRegister scratch_d,
-                               Label* on_successful_conversion,
+                               Label* on_successful_conversion = NULL,
                                Label* on_failed_conversion = NULL) {
     ASSERT(as_int.Is32Bits());
     TryConvertDoubleToInt(as_int, value, scratch_d, on_successful_conversion,
@@ -941,10 +946,12 @@ class MacroAssembler : public Assembler {
   // Try to convert a double to a signed 64-bit int.
   // This succeeds if the result compares equal to the input, so inputs of -0.0
   // are converted to 0 and handled as a success.
+  //
+  // On output the Z flag is set if the conversion was successful.
   void TryConvertDoubleToInt64(Register as_int,
                                FPRegister value,
                                FPRegister scratch_d,
-                               Label* on_successful_conversion,
+                               Label* on_successful_conversion = NULL,
                                Label* on_failed_conversion = NULL) {
     ASSERT(as_int.Is64Bits());
     TryConvertDoubleToInt(as_int, value, scratch_d, on_successful_conversion,
@@ -2071,10 +2078,12 @@ class MacroAssembler : public Assembler {
   //
   // This does not distinguish between +0 and -0, so if this distinction is
   // important it must be checked separately.
+  //
+  // On output the Z flag is set if the conversion was successful.
   void TryConvertDoubleToInt(Register as_int,
                              FPRegister value,
                              FPRegister scratch_d,
-                             Label* on_successful_conversion,
+                             Label* on_successful_conversion = NULL,
                              Label* on_failed_conversion = NULL);
 
   bool generating_stub_;