Port and integrate the irregexp engine from V8

runtime/vm/flow_graph.cc

Index: runtime/vm/flow_graph.cc
diff --git a/runtime/vm/flow_graph.cc b/runtime/vm/flow_graph.cc
index 1964a81e64331ae42df08de622514a56ad02e065..1a62d89d2577e87062d31cf5762a1ed949a986cc 100644
--- a/runtime/vm/flow_graph.cc
+++ b/runtime/vm/flow_graph.cc
@@ -793,7 +793,7 @@ void FlowGraph::RenameRecursive(BlockEntryInstr* block_entry,
                                 GrowableArray<PhiInstr*>* live_phis,
                                 VariableLivenessAnalysis* variable_liveness) {
   // 1. Process phis first.
-  if (block_entry->IsJoinEntry()) {
+  if (block_entry->IsJoinEntry() || block_entry->IsIndirectEntry()) {
     JoinEntryInstr* join = block_entry->AsJoinEntry();
     if (join->phis() != NULL) {
       for (intptr_t i = 0; i < join->phis()->length(); ++i) {
@@ -971,7 +971,8 @@ void FlowGraph::RenameRecursive(BlockEntryInstr* block_entry,
   // 4. Process successor block. We have edge-split form, so that only blocks
   // with one successor can have a join block as successor.
   if ((block_entry->last_instruction()->SuccessorCount() == 1) &&
-      block_entry->last_instruction()->SuccessorAt(0)->IsJoinEntry()) {
+      (block_entry->last_instruction()->SuccessorAt(0)->IsJoinEntry() ||
+       block_entry->last_instruction()->SuccessorAt(0)->IsIndirectEntry())) {
     JoinEntryInstr* successor =
         block_entry->last_instruction()->SuccessorAt(0)->AsJoinEntry();
     intptr_t pred_index = successor->IndexOfPredecessor(block_entry);