Implemented compare/signum intrinsics as HCompare
(with all code generation for all)

Rationale:
At HIR level, many more optimizations are possible, while ultimately
generated code can take advantage of full semantics.

Change-Id: I6e2ee0311784e5e336847346f7f3c4faef4fd17e
diff --git a/compiler/optimizing/code_generator_x86_64.h b/compiler/optimizing/code_generator_x86_64.h
index 6aa0814..72dddfd 100644
--- a/compiler/optimizing/code_generator_x86_64.h
+++ b/compiler/optimizing/code_generator_x86_64.h
@@ -479,7 +479,7 @@
   Address LiteralInt32Address(int32_t v);
   Address LiteralInt64Address(int64_t v);
 
-  // Load a 32/64 bit value into a register in the most efficient manner.
+  // Load a 32/64-bit value into a register in the most efficient manner.
   void Load32BitValue(CpuRegister dest, int32_t value);
   void Load64BitValue(CpuRegister dest, int64_t value);
   void Load32BitValue(XmmRegister dest, int32_t value);
@@ -487,6 +487,10 @@
   void Load32BitValue(XmmRegister dest, float value);
   void Load64BitValue(XmmRegister dest, double value);
 
+  // Compare a register with a 32/64-bit value in the most efficient manner.
+  void Compare32BitValue(CpuRegister dest, int32_t value);
+  void Compare64BitValue(CpuRegister dest, int64_t value);
+
   Address LiteralCaseTable(HPackedSwitch* switch_instr);
 
   // Store a 64 bit value into a DoubleStackSlot in the most efficient manner.