Port and integrate the irregexp engine from V8

runtime/vm/flow_graph_allocator.cc

Index: runtime/vm/flow_graph_allocator.cc
diff --git a/runtime/vm/flow_graph_allocator.cc b/runtime/vm/flow_graph_allocator.cc
index 03f8f2fb255f2d54c8433e31cf722270691804ff..78ab97f4c522189315b1b90986b19f65b4f105d9 100644
--- a/runtime/vm/flow_graph_allocator.cc
+++ b/runtime/vm/flow_graph_allocator.cc
@@ -218,7 +218,7 @@ void SSALivenessAnalysis::ComputeInitialSets() {
     }
 
     // Handle phis.
-    if (block->IsJoinEntry()) {
+    if (block->IsJoinEntry() || block->IsIndirectEntry()) {
       JoinEntryInstr* join = block->AsJoinEntry();
       for (PhiIterator it(join); !it.Done(); it.Advance()) {
         // TODO(johnmccutchan): Fix handling of PhiInstr with PairLocation.
@@ -575,7 +575,7 @@ void FlowGraphAllocator::BuildLiveRanges() {
       }
     }
 
-    if (block->IsJoinEntry()) {
+    if (block->IsJoinEntry() || block->IsIndirectEntry()) {
       ConnectIncomingPhiMoves(block->AsJoinEntry());
     } else if (block->IsCatchBlockEntry()) {
       // Process initial definitions.
@@ -2847,7 +2847,7 @@ void FlowGraphAllocator::CollectRepresentations() {
       }
     }
     // Phis.
-    if (block->IsJoinEntry()) {
+    if (block->IsJoinEntry() || block->IsIndirectEntry()) {
       JoinEntryInstr* join = block->AsJoinEntry();
       for (PhiIterator it(join); !it.Done(); it.Advance()) {
         // TODO(johnmccutchan): Fix handling of PhiInstr with PairLocation.