Make Throw and ReThrow instructions instead of computations. That way they can terminate a basic bl…

runtime/vm/intermediate_language.cc

Index: runtime/vm/intermediate_language.cc
===================================================================
--- runtime/vm/intermediate_language.cc	(revision 5537)
+++ runtime/vm/intermediate_language.cc	(working copy)
@@ -63,6 +63,18 @@
 }
 
 
+Instruction* ThrowInstr::Accept(FlowGraphVisitor* visitor) {
+  visitor->VisitThrow(this);
+  return NULL;
+}
+
+
+Instruction* ReThrowInstr::Accept(FlowGraphVisitor* visitor) {
+  visitor->VisitReThrow(this);
+  return NULL;
+}
+
+
 Instruction* BranchInstr::Accept(FlowGraphVisitor* visitor) {
   visitor->VisitBranch(this);
   return NULL;
@@ -132,6 +144,16 @@
 }
 
 
+void ThrowInstr::Postorder(GrowableArray<BlockEntryInstr*>* block_entries) {
+  flip_mark();
+}
+
+
+void ReThrowInstr::Postorder(GrowableArray<BlockEntryInstr*>* block_entries) {
+  flip_mark();
+}
+
+
 void BranchInstr::Postorder(GrowableArray<BlockEntryInstr*>* block_entries) {
   flip_mark();
   // Visit the false successor before the true successor so they appear in