[interpreter] Bytecode register optimizer.

test/cctest/interpreter/bytecode_expectations/CompoundExpressions.golden

 #
 # Autogenerated by generate-bytecode-expectations.
 #
 
 ---
 pool type: mixed
 execute: yes
 wrap: yes
 
 ---
 snippet: "
   var a = 1; a += 2;
 "
 frame size: 2
 parameter count: 1
-bytecode array length: 15
+bytecode array length: 16
 bytecodes: [
   /*   30 E> */ B(StackCheck),
   /*   42 S> */ B(LdaSmi), U8(1),
   /*   42 E> */ B(Star), R(0),
-  /*   45 S> */ B(Star), R(1),
-                B(LdaSmi), U8(2),
-                B(Add), R(1),
-  /*   47 E> */ B(Star), R(0),
+  /*   45 S> */ B(LdaSmi), U8(2),
+                B(Add), R(0),
+  /*   47 E> */ B(Mov), R(0), R(1),
+                B(Star), R(0),
                 B(LdaUndefined),
   /*   53 S> */ B(Return),
 ]
 constant pool: [
 ]
 handlers: [
 ]
 
 ---
 snippet: "
   var a = 1; a /= 2;
 "
 frame size: 2
 parameter count: 1
-bytecode array length: 15
+bytecode array length: 16
 bytecodes: [
   /*   30 E> */ B(StackCheck),
   /*   42 S> */ B(LdaSmi), U8(1),
   /*   42 E> */ B(Star), R(0),
-  /*   45 S> */ B(Star), R(1),
-                B(LdaSmi), U8(2),
-                B(Div), R(1),
-  /*   47 E> */ B(Star), R(0),
+  /*   45 S> */ B(LdaSmi), U8(2),
+                B(Div), R(0),
+  /*   47 E> */ B(Mov), R(0), R(1),
+                B(Star), R(0),
                 B(LdaUndefined),
   /*   53 S> */ B(Return),
 ]
 constant pool: [
 ]
 handlers: [
 ]
 
 ---
 snippet: "
   var a = { val: 2 }; a.name *= 2;
 "
 frame size: 3
 parameter count: 1
-bytecode array length: 27
+bytecode array length: 25
 bytecodes: [
   /*   30 E> */ B(StackCheck),
   /*   42 S> */ B(CreateObjectLiteral), U8(0), U8(0), U8(1),
                 B(Star), R(1),
   /*   42 E> */ B(Star), R(0),
-  /*   54 S> */ B(Star), R(1),
-                B(LoadIC), R(1), U8(1), U8(1),
+  /*   54 S> */ B(LoadIC), R(0), U8(1), U8(1),
                 B(Star), R(2),
                 B(LdaSmi), U8(2),
                 B(Mul), R(2),
-  /*   61 E> */ B(StoreICSloppy), R(1), U8(1), U8(3),
+  /*   61 E> */ B(StoreICSloppy), R(0), U8(1), U8(3),
                 B(LdaUndefined),
   /*   67 S> */ B(Return),
 ]
 constant pool: [
   InstanceType::FIXED_ARRAY_TYPE,
   InstanceType::ONE_BYTE_INTERNALIZED_STRING_TYPE,
 ]
 handlers: [
 ]
 
 ---
 snippet: "
   var a = { 1: 2 }; a[1] ^= 2;
 "
 frame size: 4
 parameter count: 1
-bytecode array length: 30
+bytecode array length: 28
 bytecodes: [
   /*   30 E> */ B(StackCheck),
   /*   42 S> */ B(CreateObjectLiteral), U8(0), U8(0), U8(1),
                 B(Star), R(1),
   /*   42 E> */ B(Star), R(0),
-  /*   52 S> */ B(Star), R(1),
-                B(LdaSmi), U8(1),
+  /*   52 S> */ B(LdaSmi), U8(1),
                 B(Star), R(2),
-                B(KeyedLoadIC), R(1), U8(1),
+                B(KeyedLoadIC), R(0), U8(1),
                 B(Star), R(3),
                 B(LdaSmi), U8(2),
                 B(BitwiseXor), R(3),
-  /*   57 E> */ B(KeyedStoreICSloppy), R(1), R(2), U8(3),
+  /*   57 E> */ B(KeyedStoreICSloppy), R(0), R(2), U8(3),
                 B(LdaUndefined),
   /*   63 S> */ B(Return),
 ]
 constant pool: [
   InstanceType::FIXED_ARRAY_TYPE,
 ]
 handlers: [
 ]
 
 ---
@@ skipping 17 matching lines @@
   /*   77 E> */ B(StaContextSlot), R(context), U8(4),
                 B(LdaUndefined),
   /*   84 S> */ B(Return),
 ]
 constant pool: [
   InstanceType::SHARED_FUNCTION_INFO_TYPE,
 ]
 handlers: [
 ]