[Interpreter] Removes unnecessary jumps and dead code from If and loops.

test/cctest/interpreter/test-interpreter.cc

 // Copyright 2015 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "src/v8.h"
 
 #include "src/execution.h"
 #include "src/handles.h"
 #include "src/interpreter/bytecode-array-builder.h"
 #include "src/interpreter/interpreter.h"
@@ skipping 2383 matching lines @@
 
 
 TEST(InterpreterDeleteSloppyUnqualifiedIdentifier) {
   HandleAndZoneScope handles;
   i::Isolate* isolate = handles.main_isolate();
   i::Factory* factory = isolate->factory();
 
   // These tests generate a syntax error for strict mode. We don't
   // test for it here.
   std::pair<const char*, Handle<Object>> test_delete[] = {
-      std::make_pair("var a = { x:10, y:'abc'};\n"
-                     "var b = delete a;\n"
-                     "if (delete a) {\n"
+      std::make_pair("var sloppy_a = { x:10, y:'abc'};\n"
+                     "var sloppy_b = delete sloppy_a;\n"
+                     "if (delete sloppy_a) {\n"
                      "  return undefined;\n"
                      "} else {\n"
-                     "  return a.x;\n"
+                     "  return sloppy_a.x;\n"
                      "}\n",
                      Handle<Object>(Smi::FromInt(10), isolate)),
       // TODO(mythria) When try-catch is implemented change the tests to check
       // if delete actually deletes
-      std::make_pair("a = { x:10, y:'abc'};\n"
-                     "var b = delete a;\n"
+      std::make_pair("sloppy_a = { x:10, y:'abc'};\n"
+                     "var sloppy_b = delete sloppy_a;\n"
                      // "try{return a.x;} catch(e) {return b;}\n"
-                     "return b;",
+                     "return sloppy_b;",
                      factory->ToBoolean(true)),
-      std::make_pair("a = { x:10, y:'abc'};\n"
-                     "var b = delete c;\n"
-                     "return b;",
+      std::make_pair("sloppy_a = { x:10, y:'abc'};\n"
+                     "var sloppy_b = delete sloppy_c;\n"
+                     "return sloppy_b;",
                      factory->ToBoolean(true))};
 
 
   for (size_t i = 0; i < arraysize(test_delete); i++) {
     std::string source(InterpreterTester::SourceForBody(test_delete[i].first));
     InterpreterTester tester(handles.main_isolate(), source.c_str());
     auto callable = tester.GetCallable<>();
 
     Handle<i::Object> return_value = callable().ToHandleChecked();
     CHECK(return_value->SameValue(*test_delete[i].second));
@@ skipping 59 matching lines @@
 
   for (size_t i = 0; i < arraysize(test_global_delete); i++) {
     InterpreterTester tester(handles.main_isolate(),
                              test_global_delete[i].first);
     auto callable = tester.GetCallable<>();
 
     Handle<i::Object> return_value = callable().ToHandleChecked();
     CHECK(return_value->SameValue(*test_global_delete[i].second));
   }
 }
+
+
+TEST(InterpreterLoops) {
+  HandleAndZoneScope handles;
+  i::Isolate* isolate = handles.main_isolate();
+  i::Factory* factory = isolate->factory();
+
+  std::pair<const char*, Handle<Object>> test_loop[] = {
+      std::make_pair("var a = 10; var b = 1;\n"
+                     "while (false) {\n"
+                     "  b = b * 2;\n"
+                     "  a = a - 1;\n"
+                     "}\n"
+                     "return b;\n",
+                     Handle<Object>(Smi::FromInt(1), isolate)),
+      std::make_pair("var a = 10; var b = 1;\n"
+                     "while (true) {\n"
+                     "  b = b * 2;\n"
+                     "  a = a - 1;\n"
+                     "  if (a == 0) break;"
+                     "  continue;"
+                     "}\n"
+                     "return b;\n",
+                     factory->NewHeapNumber(1024)),
+      std::make_pair("var a = 10; var b = 1;\n"
+                     "do {\n"
+                     "  b = b * 2;\n"
+                     "  a = a - 1;\n"
+                     "  if (a == 0) break;"
+                     "} while(true);\n"
+                     "return b;\n",
+                     factory->NewHeapNumber(1024)),
+      std::make_pair("var a = 10; var b = 1;\n"
+                     "do {\n"
+                     "  b = b * 2;\n"
+                     "  a = a - 1;\n"
+                     "  if (a == 0) break;"
+                     "} while(false);\n"
+                     "return b;\n",
+                     Handle<Object>(Smi::FromInt(2), isolate)),
+      std::make_pair("var a = 10; var b = 1;\n"
+                     "for ( a = 1, b = 30; false; ) {\n"
+                     "  b = b * 2;\n"
+                     "}\n"
+                     "return b;\n",
+                     Handle<Object>(Smi::FromInt(30), isolate))};
+
+  for (size_t i = 0; i < arraysize(test_loop); i++) {
+    std::string source(InterpreterTester::SourceForBody(test_loop[i].first));
+    InterpreterTester tester(handles.main_isolate(), source.c_str());
+    auto callable = tester.GetCallable<>();
+
+    Handle<i::Object> return_value = callable().ToHandleChecked();
+    CHECK(return_value->SameValue(*test_loop[i].second));
+  }
+}