A64: Rejig truncating and non double to i/smi

src/a64/macro-assembler-a64.cc

 // Copyright 2013 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 1829 matching lines @@
 
   if (on_successful_conversion) {
     B(on_successful_conversion, eq);
   }
   if (on_failed_conversion) {
     B(on_failed_conversion, ne);
   }
 }
 
 
+void MacroAssembler::JumpIfMinusZero(DoubleRegister input,
+                                     Label* on_negative_zero) {
+  // Floating point -0.0 is kMinInt as an integer, so subtracting 1 (cmp) will
+  // cause overflow.
+  Fmov(Tmp0(), input);
+  Cmp(Tmp0(), 1);
+  B(vs, on_negative_zero);
+}
+
+
 void MacroAssembler::ClampInt32ToUint8(Register output, Register input) {
   // Clamp the value to [0..255].
   Cmp(input.W(), Operand(input.W(), UXTB));
   // If input < input & 0xff, it must be < 0, so saturate to 0.
   Csel(output.W(), wzr, input.W(), lt);
   // Create a constant 0xff.
   Mov(WTmp0(), 255);
   // If input > input & 0xff, it must be > 255, so saturate to 255.
   Csel(output.W(), WTmp0(), output.W(), gt);
 }
@@ skipping 2834 matching lines @@
   }
 }
 
 
 #undef __
 
 
 } }  // namespace v8::internal
 
 #endif  // V8_TARGET_ARCH_A64