VM(RegExp): Allow OSR optimization of RegExp :matcher functions.

runtime/vm/flow_graph_builder.cc

Index: runtime/vm/flow_graph_builder.cc
diff --git a/runtime/vm/flow_graph_builder.cc b/runtime/vm/flow_graph_builder.cc
index e0e279513ee5fb8b9c5235ee4263df3145460bbe..625944169ffbaff84639f117060239afb209f29b 100644
--- a/runtime/vm/flow_graph_builder.cc
+++ b/runtime/vm/flow_graph_builder.cc
@@ -4471,7 +4471,7 @@ FlowGraph* FlowGraphBuilder::BuildGraph() {
   // unreachable from the OSR entry. Catch entries are always considered
   // reachable, even if they become unreachable after OSR.
   if (osr_id_ != Compiler::kNoOSRDeoptId) {
-    PruneUnreachable();
+    graph_entry_->PruneUnreachableForOSR(Z, last_used_block_id_);
   }
 
   FlowGraph* graph =
@@ -4486,15 +4486,6 @@ void FlowGraphBuilder::AppendAwaitTokenPosition(TokenPosition token_pos) {
 }
 
 
-void FlowGraphBuilder::PruneUnreachable() {
-  ASSERT(osr_id_ != Compiler::kNoOSRDeoptId);
-  BitVector* block_marks = new (Z) BitVector(Z, last_used_block_id_ + 1);
-  bool found =
-      graph_entry_->PruneUnreachable(graph_entry_, NULL, osr_id_, block_marks);
-  ASSERT(found);
-}
-
-
 void FlowGraphBuilder::Bailout(const char* reason) const {
   parsed_function_.Bailout("FlowGraphBuilder", reason);
 }