Streamline code generator for branches and comparisons.

runtime/vm/flow_graph_compiler.cc

Index: runtime/vm/flow_graph_compiler.cc
===================================================================
--- runtime/vm/flow_graph_compiler.cc	(revision 30153)
+++ runtime/vm/flow_graph_compiler.cc	(working copy)
@@ -317,13 +317,26 @@
 }
 
 
-bool FlowGraphCompiler::CanFallThroughTo(BlockEntryInstr* block_entry) const {
+Label* FlowGraphCompiler::NextNonEmptyLabel() const {
   const intptr_t current_index = current_block()->postorder_number();
-  Label* next_nonempty = block_info_[current_index]->next_nonempty_label();
-  return next_nonempty == GetJumpLabel(block_entry);
+  return block_info_[current_index]->next_nonempty_label();
 }
 
 
+bool FlowGraphCompiler::CanFallThroughTo(BlockEntryInstr* block_entry) const {
+  return NextNonEmptyLabel() == GetJumpLabel(block_entry);
+}
+
+
+BranchLabels FlowGraphCompiler::CreateBranchLabels(BranchInstr* branch) const {
+  Label* true_label = GetJumpLabel(branch->true_successor());
+  Label* false_label = GetJumpLabel(branch->false_successor());
+  Label* fall_through = NextNonEmptyLabel();
+  BranchLabels result = { true_label, false_label, fall_through };
+  return result;
+}
+
+
 void FlowGraphCompiler::AddSlowPathCode(SlowPathCode* code) {
   slow_path_code_.Add(code);
 }