[interpreter] Bytecode register optimizer.

test/cctest/interpreter/bytecode_expectations/BreakableBlocks.golden

 #
 # Autogenerated by generate-bytecode-expectations.
 #
 
 ---
 pool type: mixed
 execute: yes
 wrap: yes
 
 ---
 snippet: "
   var x = 0;
   label: {
     x = x + 1;
     break label;
     x = x + 1;
   }
   return x;
 "
-frame size: 2
+frame size: 1
 parameter count: 1
-bytecode array length: 17
+bytecode array length: 15
 bytecodes: [
   /*   30 E> */ B(StackCheck),
   /*   42 S> */ B(LdaZero),
                 B(Star), R(0),
-  /*   56 S> */ B(Star), R(1),
-                B(LdaSmi), U8(1),
-                B(Add), R(1),
+  /*   56 S> */ B(LdaSmi), U8(1),
+                B(Add), R(0),
                 B(Star), R(0),
   /*   69 S> */ B(Jump), U8(2),
   /*   97 S> */ B(Ldar), R(0),
   /*  107 S> */ B(Return),
 ]
 constant pool: [
 ]
 handlers: [
 ]
 
 ---
 snippet: "
   var sum = 0;
   outer: {
     for (var x = 0; x < 10; ++x) {
       for (var y = 0; y < 3; ++y) {
         ++sum;
         if (x + y == 12) { break outer; }
       }
     }
   }
   return sum;
 "
 frame size: 5
 parameter count: 1
-bytecode array length: 72
+bytecode array length: 61
 bytecodes: [
   /*   30 E> */ B(StackCheck),
   /*   44 S> */ B(LdaZero),
                 B(Star), R(0),
   /*   71 S> */ B(LdaZero),
   /*   71 E> */ B(Star), R(1),
-  /*   76 S> */ B(Ldar), R(1),
-                B(Star), R(3),
-                B(LdaSmi), U8(10),
-  /*   76 E> */ B(TestLessThan), R(3),
-                B(JumpIfFalse), U8(54),
+  /*   76 S> */ B(LdaSmi), U8(10),
+  /*   76 E> */ B(TestLessThan), R(1),
+                B(JumpIfFalse), U8(47),
   /*   58 E> */ B(StackCheck),
   /*  106 S> */ B(LdaZero),
   /*  106 E> */ B(Star), R(2),
-  /*  111 S> */ B(Ldar), R(2),
-                B(Star), R(3),
-                B(LdaSmi), U8(3),
-  /*  111 E> */ B(TestLessThan), R(3),
-                B(JumpIfFalse), U8(33),
+  /*  111 S> */ B(LdaSmi), U8(3),
+  /*  111 E> */ B(TestLessThan), R(2),
+                B(JumpIfFalse), U8(30),
   /*   93 E> */ B(StackCheck),
   /*  129 S> */ B(Ldar), R(0),
                 B(Inc),
                 B(Star), R(0),
-  /*  142 S> */ B(Ldar), R(1),
-                B(Star), R(3),
+  /*  142 S> */ B(Nop),
   /*  150 E> */ B(Ldar), R(2),
-                B(Add), R(3),
+                B(Add), R(1),
                 B(Star), R(4),
                 B(LdaSmi), U8(12),
   /*  152 E> */ B(TestEqual), R(4),
                 B(JumpIfFalse), U8(4),
   /*  161 S> */ B(Jump), U8(16),
   /*  118 S> */ B(Ldar), R(2),
                 B(Inc),
   /*  118 E> */ B(Star), R(2),
-                B(Jump), U8(-39),
+                B(Jump), U8(-32),
   /*   84 S> */ B(Ldar), R(1),
                 B(Inc),
   /*   84 E> */ B(Star), R(1),
-                B(Jump), U8(-60),
+                B(Jump), U8(-49),
   /*  188 S> */ B(Ldar), R(0),
   /*  200 S> */ B(Return),
 ]
 constant pool: [
 ]
 handlers: [
 ]
 
 ---
 snippet: "
   outer: {
     let y = 10;
     function f() { return y; }
     break outer;
   }
 "
 frame size: 5
 parameter count: 1
-bytecode array length: 51
+bytecode array length: 50
 bytecodes: [
   /*   30 E> */ B(StackCheck),
                 B(LdaConstant), U8(0),
                 B(Star), R(3),
-                B(Ldar), R(closure),
-                B(Star), R(4),
+                B(Mov), R(closure), R(4),
                 B(CallRuntime), U16(Runtime::kPushBlockContext), R(3), U8(2),
                 B(PushContext), R(2),
                 B(LdaTheHole),
                 B(StaContextSlot), R(context), U8(4),
                 B(CreateClosure), U8(1), U8(0),
                 B(Star), R(0),
   /*   53 S> */ B(LdaSmi), U8(10),
   /*   53 E> */ B(StaContextSlot), R(context), U8(4),
                 B(Ldar), R(0),
                 B(JumpIfNotHole), U8(11),
@@ skipping 22 matching lines @@
      let y = 2;
       function f() { return x + y; }
       if (y) break outer;
       y = 3;
     }
   }
   x = 4;
 "
 frame size: 6
 parameter count: 1
-bytecode array length: 131
+bytecode array length: 130
 bytecodes: [
                 B(CallRuntime), U16(Runtime::kNewFunctionContext), R(closure), U8(1),
                 B(PushContext), R(2),
                 B(LdaTheHole),
                 B(StaContextSlot), R(context), U8(4),
   /*   30 E> */ B(StackCheck),
   /*   42 S> */ B(LdaSmi), U8(1),
   /*   42 E> */ B(StaContextSlot), R(context), U8(4),
                 B(LdaConstant), U8(0),
                 B(Star), R(4),
-                B(Ldar), R(closure),
-                B(Star), R(5),
+                B(Mov), R(closure), R(5),
                 B(CallRuntime), U16(Runtime::kPushBlockContext), R(4), U8(2),
                 B(PushContext), R(3),
                 B(LdaTheHole),
                 B(StaContextSlot), R(context), U8(4),
                 B(CreateClosure), U8(1), U8(0),
                 B(Star), R(0),
   /*   76 S> */ B(LdaSmi), U8(2),
   /*   76 E> */ B(StaContextSlot), R(context), U8(4),
                 B(Ldar), R(0),
                 B(JumpIfNotHole), U8(11),
@@ skipping 34 matching lines @@
 constant pool: [
   InstanceType::FIXED_ARRAY_TYPE,
   InstanceType::SHARED_FUNCTION_INFO_TYPE,
   InstanceType::ONE_BYTE_INTERNALIZED_STRING_TYPE,
   InstanceType::ONE_BYTE_INTERNALIZED_STRING_TYPE,
   InstanceType::ONE_BYTE_INTERNALIZED_STRING_TYPE,
 ]
 handlers: [
 ]