[turbofan] Clean up and factor out branch generation logic.

src/compiler/code-generator.h

Index: src/compiler/code-generator.h
diff --git a/src/compiler/code-generator.h b/src/compiler/code-generator.h
index b03e2add31192a19d8fe33d571f5e4c5555558a7..2a3ade52a2c1f4b03a83b19b8a4447ba6b1ece23 100644
--- a/src/compiler/code-generator.h
+++ b/src/compiler/code-generator.h
@@ -19,6 +19,14 @@ namespace compiler {
 
 class Linkage;
 
+struct BranchInfo {
+  FlagsCondition condition;
+  Label* true_label;
+  Label* false_label;
+  bool fallthru;
+};
+
+
 // Generates native code for a sequence of instructions.
 class CodeGenerator FINAL : public GapResolver::Assembler {
  public:
@@ -60,7 +68,8 @@ class CodeGenerator FINAL : public GapResolver::Assembler {
   // ===========================================================================
 
   void AssembleArchInstruction(Instruction* instr);
-  void AssembleArchBranch(Instruction* instr, FlagsCondition condition);
+  void AssembleArchJump(BasicBlock::RpoNumber target);
+  void AssembleArchBranch(Instruction* instr, BranchInfo* branch);
   void AssembleArchBoolean(Instruction* instr, FlagsCondition condition);
 
   void AssembleDeoptimizerCall(int deoptimization_id);