[interpreter] Bytecode register optimizer.

test/cctest/interpreter/bytecode_expectations/CompoundExpressions.golden

Index: test/cctest/interpreter/bytecode_expectations/CompoundExpressions.golden
diff --git a/test/cctest/interpreter/bytecode_expectations/CompoundExpressions.golden b/test/cctest/interpreter/bytecode_expectations/CompoundExpressions.golden
index a78e6f5f2cd9ba51ffe38fd9fbc9acb17971912c..5f3658398f4087ea05041fb10cff985abc5d314d 100644
--- a/test/cctest/interpreter/bytecode_expectations/CompoundExpressions.golden
+++ b/test/cctest/interpreter/bytecode_expectations/CompoundExpressions.golden
@@ -13,15 +13,15 @@ snippet: "
 "
 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),
                 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),
 ]
@@ -36,15 +36,15 @@ snippet: "
 "
 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),
                 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),
 ]
@@ -59,17 +59,17 @@ snippet: "
 "
 frame size: 3
 parameter count: 1
-bytecode array length: 26
+bytecode array length: 25
 bytecodes: [
   /*   30 E> */ B(StackCheck),
   /*   42 S> */ B(CreateObjectLiteral), U8(0), U8(0), U8(1),
                 B(Star), R(1),
                 B(Star), R(0),
-  /*   54 S> */ B(Star), R(1),
-                B(LdrNamedProperty), R(1), U8(1), U8(1), R(2),
+  /*   54 S> */ B(LdaNamedProperty), R(0), U8(1), U8(1),
+                B(Star), R(2),
                 B(LdaSmi), U8(2),
                 B(Mul), R(2),
-  /*   61 E> */ B(StaNamedPropertySloppy), R(1), U8(1), U8(3),
+  /*   61 E> */ B(StaNamedPropertySloppy), R(0), U8(1), U8(3),
                 B(LdaUndefined),
   /*   67 S> */ B(Return),
 ]
@@ -86,19 +86,19 @@ snippet: "
 "
 frame size: 4
 parameter count: 1
-bytecode array length: 29
+bytecode array length: 28
 bytecodes: [
   /*   30 E> */ B(StackCheck),
   /*   42 S> */ B(CreateObjectLiteral), U8(0), U8(0), U8(1),
                 B(Star), R(1),
                 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(LdrKeyedProperty), R(1), U8(1), R(3),
+                B(LdaKeyedProperty), R(0), U8(1),
+                B(Star), R(3),
                 B(LdaSmi), U8(2),
                 B(BitwiseXor), R(3),
-  /*   57 E> */ B(StaKeyedPropertySloppy), R(1), R(2), U8(3),
+  /*   57 E> */ B(StaKeyedPropertySloppy), R(0), R(2), U8(3),
                 B(LdaUndefined),
   /*   63 S> */ B(Return),
 ]
@@ -114,7 +114,7 @@ snippet: "
 "
 frame size: 2
 parameter count: 1
-bytecode array length: 29
+bytecode array length: 30
 bytecodes: [
                 B(CallRuntime), U16(Runtime::kNewFunctionContext), R(closure), U8(1),
                 B(PushContext), R(0),
@@ -122,7 +122,8 @@ bytecodes: [
   /*   42 S> */ B(LdaSmi), U8(1),
   /*   42 E> */ B(StaContextSlot), R(context), U8(4),
   /*   45 S> */ B(CreateClosure), U8(0), U8(0),
-  /*   75 S> */ B(LdrContextSlot), R(context), U8(4), R(1),
+  /*   75 S> */ B(LdaContextSlot), R(context), U8(4),
+                B(Star), R(1),
                 B(LdaSmi), U8(24),
                 B(BitwiseOr), R(1),
   /*   77 E> */ B(StaContextSlot), R(context), U8(4),