Use classifying token position for control flow IR instructions

runtime/vm/flow_graph_builder_test.cc

 // Copyright (c) 2016, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #include "vm/compiler.h"
 #include "vm/dart_api_impl.h"
 #include "vm/dart_entry.h"
 #include "vm/flow_graph_builder.h"
 #include "vm/intermediate_language.h"
 #include "vm/unit_test.h"
@@ skipping 519 matching lines @@
 
   spt.FuzzyInstructionMatchAt("LoadLocal(z", 8, 8);
   spt.InstanceCallAt(8, 7, Token::kBIT_NOT);
   spt.FuzzyInstructionMatchAt("StoreLocal(z", 8, 3);
 
   spt.FuzzyInstructionMatchAt("LoadLocal(z", 9, 10);
   spt.FuzzyInstructionMatchAt("DebugStepCheck", 9, 3);
   spt.FuzzyInstructionMatchAt("Return", 9, 3);
 }
 
+
+TEST_CASE(SourcePosition_IfElse) {
+  const char* kScript =
+      "var x = 5;\n"
+      "var y = 5;\n"
+      "main() {\n"
+      "  if (x != 0) {\n"
+      "    return x;\n"
+      "  } else {\n"
+      "    return y;\n"
+      "  }\n"
+      "}\n";
+
+  SourcePositionTest spt(thread, kScript);
+  spt.BuildGraphFor("main");
+  spt.FuzzyInstructionMatchAt("DebugStepCheck", 3, 5);
+  spt.FuzzyInstructionMatchAt("CheckStackOverflow", 3, 5);
+  spt.FuzzyInstructionMatchAt("LoadStaticField", 4, 7);
+  spt.InstanceCallAt(4, 9, Token::kEQ);
+  spt.FuzzyInstructionMatchAt("Branch if StrictCompare", 4, 9);
+  spt.FuzzyInstructionMatchAt("LoadStaticField", 5, 12);
+  spt.FuzzyInstructionMatchAt("DebugStepCheck", 5, 5);
+  spt.FuzzyInstructionMatchAt("Return", 5, 5);
+  spt.FuzzyInstructionMatchAt("LoadStaticField", 7, 10);
+  spt.FuzzyInstructionMatchAt("DebugStepCheck", 7, 3);
+  spt.FuzzyInstructionMatchAt("Return", 7, 3);
+}
+
 }  // namespace dart