Rewrite HInstruction::Is/As<type>().

Make Is<type>() and As<type>() non-virtual for concrete
instruction types, relying on GetKind(), and mark GetKind()
as PURE to improve optimization opportunities. This reduces
the number of relocations in libart-compiler.so's .rel.dyn
section by ~4K, or ~44%, and in .data.rel.ro by ~18K, or
~65%. The file is 96KiB smaller for Nexus 5, including 8KiB
reduction of the .text section.

Unfortunately, the g++/clang++ __attribute__((pure)) is not
strong enough to avoid duplicated virtual calls and we would
need the C++ [[pure]] attribute proposed in n3744 instead.
To work around this deficiency, we introduce an extra
non-virtual indirection for GetKind(), so that the compiler
can optimize common expressions such as
    instruction->IsAdd() || instruction->IsSub()
or
    instruction->IsAdd() && instruction->AsAdd()->...
which contain two virtual calls to GetKind() after inlining.

Change-Id: I83787de0671a5cb9f5b0a5f4a536cef239d5b401
diff --git a/compiler/optimizing/code_generator_x86.h b/compiler/optimizing/code_generator_x86.h
index f0ead03..3d34317 100644
--- a/compiler/optimizing/code_generator_x86.h
+++ b/compiler/optimizing/code_generator_x86.h
@@ -167,6 +167,7 @@
  private:
   void HandleBitwiseOperation(HBinaryOperation* instruction);
   void HandleInvoke(HInvoke* invoke);
+  void HandleCondition(HCondition* condition);
   void HandleShift(HBinaryOperation* instruction);
   void HandleFieldSet(HInstruction* instruction, const FieldInfo& field_info);
   void HandleFieldGet(HInstruction* instruction, const FieldInfo& field_info);
@@ -213,6 +214,7 @@
   void DivByPowerOfTwo(HDiv* instruction);
   void GenerateDivRemWithAnyConstant(HBinaryOperation* instruction);
   void GenerateRemFP(HRem* rem);
+  void HandleCondition(HCondition* condition);
   void HandleShift(HBinaryOperation* instruction);
   void GenerateShlLong(const Location& loc, Register shifter);
   void GenerateShrLong(const Location& loc, Register shifter);