Opt compiler: Implement parallel move resolver without using swap.

The algorithm of ParallelMoveResolverNoSwap() is almost the same with
ParallelMoveResolverWithSwap(), except the way we resolve the circular
dependency. NoSwap() uses additional scratch register to resolve the
circular dependency. For example, (0->1) (1->2) (2->0) will be performed
as (2->scratch) (1->2) (0->1) (scratch->0).

On architectures without swap register support, NoSwap() can reduce the
number of moves from 3x(N-1) to (N+1) when there is circular dependency
with N moves.

And also, NoSwap() algorithm does not depend on architecture register
layout information, which means it can support register pairs on arm32
and X/W, D/S registers on arm64 without additional modification.

Change-Id: Idf56bd5469bb78c0e339e43ab16387428a082318

1 files changed, 2 insertions, 2 deletions

diff --git a/compiler/optimizing/code_generator_arm.h b/compiler/optimizing/code_generator_arm.h
index 06f425ea21..600903621d 100644
--- a/compiler/optimizing/code_generator_arm.h
+++ b/compiler/optimizing/code_generator_arm.h
@@ -96,10 +96,10 @@ class InvokeDexCallingConventionVisitor {
   DISALLOW_COPY_AND_ASSIGN(InvokeDexCallingConventionVisitor);
 };
 
-class ParallelMoveResolverARM : public ParallelMoveResolver {
+class ParallelMoveResolverARM : public ParallelMoveResolverWithSwap {
  public:
   ParallelMoveResolverARM(ArenaAllocator* allocator, CodeGeneratorARM* codegen)
-      : ParallelMoveResolver(allocator), codegen_(codegen) {}
+      : ParallelMoveResolverWithSwap(allocator), codegen_(codegen) {}
 
   void EmitMove(size_t index) OVERRIDE;
   void EmitSwap(size_t index) OVERRIDE;