Reapply "Inlining of static calls with trivial function bodies."

runtime/vm/compiler.cc

Index: runtime/vm/compiler.cc
diff --git a/runtime/vm/compiler.cc b/runtime/vm/compiler.cc
index 56717e0e20702bb34512805dec63c2de08f3ac09..f331f69ff80fe449eb957028b77445a263f69668 100644
--- a/runtime/vm/compiler.cc
+++ b/runtime/vm/compiler.cc
@@ -17,6 +17,7 @@
 #include "vm/flow_graph_allocator.h"
 #include "vm/flow_graph_builder.h"
 #include "vm/flow_graph_compiler.h"
+#include "vm/flow_graph_inliner.h"
 #include "vm/flow_graph_optimizer.h"
 #include "vm/il_printer.h"
 #include "vm/longjump.h"
@@ -38,6 +39,7 @@ DEFINE_FLAG(bool, cse, true, "Do common subexpression elimination.");
 DEFINE_FLAG(int, deoptimization_counter_threshold, 5,
     "How many times we allow deoptimization before we disallow"
     " certain optimizations");
+DEFINE_FLAG(bool, use_inlining, true, "Enable call-site inlining");
 DECLARE_FLAG(bool, print_flow_graph);
 
 
@@ -189,6 +191,14 @@ static bool CompileParsedFunctionHelper(const ParsedFunction& parsed_function,
         // Compute the use lists.
         flow_graph->ComputeUseLists();
 
+        // Inlining (mutates the flow graph)
+        if (FLAG_use_inlining) {
+          FlowGraphInliner inliner(flow_graph);
+          inliner.Inline();
+          // Verify that the use lists are still valid.
+          DEBUG_ASSERT(flow_graph->ValidateUseLists());
+        }
+
         // Propagate types and eliminate more type tests.
         FlowGraphTypePropagator propagator(*flow_graph);
         propagator.PropagateTypes();