[interpreter] Bytecode register optimizer.

test/cctest/interpreter/bytecode_expectations/IfConditions.golden

 #
 # Autogenerated by generate-bytecode-expectations.
 #
 
 ---
 pool type: mixed
 execute: yes
 wrap: no
 test function name: f
 
@@ skipping 98 matching lines @@
     if (a) {
       a += 1;
     } else {
       return 2;
     }
   };
   f();
 "
 frame size: 2
 parameter count: 1
-bytecode array length: 24
+bytecode array length: 23
 bytecodes: [
   /*   10 E> */ B(StackCheck),
   /*   25 S> */ B(LdaSmi), U8(1),
                 B(Star), R(0),
-  /*   30 S> */ B(JumpIfToBooleanFalse), U8(14),
-  /*   43 S> */ B(Ldar), R(0),
-                B(Star), R(1),
-                B(LdaSmi), U8(1),
-                B(Add), R(1),
+  /*   30 S> */ B(JumpIfToBooleanFalse), U8(13),
+  /*   43 S> */ B(LdaSmi), U8(1),
+                B(Add), R(0),
+                B(Mov), R(0), R(1),
   /*   45 E> */ B(Star), R(0),
                 B(Jump), U8(5),
   /*   66 S> */ B(LdaSmi), U8(2),
   /*   80 S> */ B(Return),
                 B(LdaUndefined),
   /*   80 S> */ B(Return),
 ]
 constant pool: [
 ]
 handlers: [
 ]
 
 ---
 snippet: "
   function f(a) {
     if (a <= 0) {
       return 200;
     } else {
       return -200;
     }
   };
   f(99);
 "
-frame size: 1
+frame size: 0
 parameter count: 2
-bytecode array length: 22
+bytecode array length: 18
 bytecodes: [
   /*   10 E> */ B(StackCheck),
-  /*   18 S> */ B(Ldar), R(arg0),
-                B(Star), R(0),
-                B(LdaZero),
-  /*   24 E> */ B(TestLessThanOrEqual), R(0),
+  /*   18 S> */ B(LdaZero),
+  /*   24 E> */ B(TestLessThanOrEqual), R(arg0),
                 B(JumpIfFalse), U8(7),
   /*   36 S> */ B(Wide), B(LdaSmi), U16(200),
   /*   80 S> */ B(Return),
   /*   63 S> */ B(Wide), B(LdaSmi), U16(-200),
   /*   80 S> */ B(Return),
                 B(LdaUndefined),
   /*   80 S> */ B(Return),
 ]
 constant pool: [
 ]
 handlers: [
 ]
 
 ---
 snippet: "
   function f(a, b) { if (a in b) { return 200; } }f('prop', { prop: 'yes'});
 "
-frame size: 1
+frame size: 0
 parameter count: 3
-bytecode array length: 18
+bytecode array length: 15
 bytecodes: [
   /*   10 E> */ B(StackCheck),
-  /*   19 S> */ B(Ldar), R(arg0),
-                B(Star), R(0),
+  /*   19 S> */ B(Nop),
   /*   28 E> */ B(Ldar), R(arg1),
-  /*   25 E> */ B(TestIn), R(0),
+  /*   25 E> */ B(TestIn), R(arg0),
                 B(JumpIfFalse), U8(7),
   /*   33 S> */ B(Wide), B(LdaSmi), U16(200),
   /*   47 S> */ B(Return),
                 B(LdaUndefined),
   /*   47 S> */ B(Return),
 ]
 constant pool: [
 ]
 handlers: [
 ]
@@ skipping 60 matching lines @@
     b = a; a = b;
     b = a; a = b;
     b = a; a = b;
     b = a; a = b;
     b = a; a = b;
     b = a; a = b;
     b = a; a = b;
     b = a; a = b;
    return 200; } else { return -200; } } f(0.001);
 "
-frame size: 3
+frame size: 2
 parameter count: 2
-bytecode array length: 414
+bytecode array length: 410
 bytecodes: [
   /*   10 E> */ B(StackCheck),
   /*   24 S> */ B(LdaZero),
                 B(Star), R(0),
   /*   35 S> */ B(LdaZero),
                 B(Star), R(1),
-  /*   38 S> */ B(Ldar), R(0),
-                B(Star), R(2),
-                B(LdaConstant), U8(0),
-  /*   44 E> */ B(TestEqualStrict), R(2),
+  /*   38 S> */ B(LdaConstant), U8(0),
+  /*   44 E> */ B(TestEqualStrict), R(0),
                 B(JumpIfFalseConstant), U8(1),
-  /*   58 S> */ B(Ldar), R(0),
-                B(Star), R(1),
+  /*   58 S> */ B(Nop),
+                B(Mov), R(0), R(1),
   /*   65 S> */ B(Nop),
-                B(Star), R(0),
-  /*   74 S> */ B(Nop),
-                B(Star), R(1),
+                B(Mov), R(0), R(0),
+  /*   74 S> */ B(Ldar), R(1),

[oth, 2016/05/26 21:26:51]

TODO(oth): review. This would be wrong if the debugger live edited one of these
variables. Changed following patch set 11.

   /*   81 S> */ B(Nop),
                 B(Star), R(0),
   /*   90 S> */ B(Nop),
                 B(Star), R(1),
   /*   97 S> */ B(Nop),
                 B(Star), R(0),
   /*  106 S> */ B(Nop),
                 B(Star), R(1),
   /*  113 S> */ B(Nop),
                 B(Star), R(0),
@@ skipping 328 matching lines @@
 parameter count: 1
 bytecode array length: 408
 bytecodes: [
   /*   10 E> */ B(StackCheck),
   /*   25 S> */ B(LdaZero),
                 B(Star), R(0),
   /*   36 S> */ B(LdaZero),
                 B(Star), R(1),
   /*   41 S> */ B(Ldar), R(0),
                 B(JumpIfToBooleanFalseConstant), U8(0),
-  /*   52 S> */ B(Ldar), R(0),
-                B(Star), R(1),
+  /*   52 S> */ B(Nop),
+                B(Mov), R(0), R(1),
   /*   59 S> */ B(Nop),
-                B(Star), R(0),
-  /*   68 S> */ B(Nop),
-                B(Star), R(1),
+                B(Mov), R(0), R(0),
+  /*   68 S> */ B(Ldar), R(1),
   /*   75 S> */ B(Nop),
                 B(Star), R(0),
   /*   84 S> */ B(Nop),
                 B(Star), R(1),
   /*   91 S> */ B(Nop),
                 B(Star), R(0),
   /*  100 S> */ B(Nop),
                 B(Star), R(1),
   /*  107 S> */ B(Nop),
                 B(Star), R(0),
@@ skipping 258 matching lines @@
     if (a < b) { return 1; }
     if (a > b) { return 1; }
     if (a <= b) { return 1; }
     if (a >= b) { return 1; }
     if (a in b) { return 1; }
     if (a instanceof b) { return 1; }
     return 0;
   }
   f(1, 1);
 "
-frame size: 1
+frame size: 0
 parameter count: 3
-bytecode array length: 107
+bytecode array length: 83
 bytecodes: [
   /*   10 E> */ B(StackCheck),
-  /*   21 S> */ B(Ldar), R(arg0),
-                B(Star), R(0),
+  /*   21 S> */ B(Nop),
   /*   30 E> */ B(Ldar), R(arg1),
-  /*   27 E> */ B(TestEqual), R(0),
+  /*   27 E> */ B(TestEqual), R(arg0),
                 B(JumpIfFalse), U8(5),
   /*   35 S> */ B(LdaSmi), U8(1),
   /*  262 S> */ B(Return),
-  /*   49 S> */ B(Ldar), R(arg0),
-                B(Star), R(0),
+  /*   49 S> */ B(Nop),
   /*   59 E> */ B(Ldar), R(arg1),
-  /*   55 E> */ B(TestEqualStrict), R(0),
+  /*   55 E> */ B(TestEqualStrict), R(arg0),
                 B(JumpIfFalse), U8(5),
   /*   64 S> */ B(LdaSmi), U8(1),
   /*  262 S> */ B(Return),
-  /*   78 S> */ B(Ldar), R(arg0),
-                B(Star), R(0),
+  /*   78 S> */ B(Nop),
   /*   86 E> */ B(Ldar), R(arg1),
-  /*   84 E> */ B(TestLessThan), R(0),
+  /*   84 E> */ B(TestLessThan), R(arg0),
                 B(JumpIfFalse), U8(5),
   /*   91 S> */ B(LdaSmi), U8(1),
   /*  262 S> */ B(Return),
-  /*  105 S> */ B(Ldar), R(arg0),
-                B(Star), R(0),
+  /*  105 S> */ B(Nop),
   /*  113 E> */ B(Ldar), R(arg1),
-  /*  111 E> */ B(TestGreaterThan), R(0),
+  /*  111 E> */ B(TestGreaterThan), R(arg0),
                 B(JumpIfFalse), U8(5),
   /*  118 S> */ B(LdaSmi), U8(1),
   /*  262 S> */ B(Return),
-  /*  132 S> */ B(Ldar), R(arg0),
-                B(Star), R(0),
+  /*  132 S> */ B(Nop),
   /*  141 E> */ B(Ldar), R(arg1),
-  /*  138 E> */ B(TestLessThanOrEqual), R(0),
+  /*  138 E> */ B(TestLessThanOrEqual), R(arg0),
                 B(JumpIfFalse), U8(5),
   /*  146 S> */ B(LdaSmi), U8(1),
   /*  262 S> */ B(Return),
-  /*  160 S> */ B(Ldar), R(arg0),
-                B(Star), R(0),
+  /*  160 S> */ B(Nop),
   /*  169 E> */ B(Ldar), R(arg1),
-  /*  166 E> */ B(TestGreaterThanOrEqual), R(0),
+  /*  166 E> */ B(TestGreaterThanOrEqual), R(arg0),
                 B(JumpIfFalse), U8(5),
   /*  174 S> */ B(LdaSmi), U8(1),
   /*  262 S> */ B(Return),
-  /*  188 S> */ B(Ldar), R(arg0),
-                B(Star), R(0),
+  /*  188 S> */ B(Nop),
   /*  197 E> */ B(Ldar), R(arg1),
-  /*  194 E> */ B(TestIn), R(0),
+  /*  194 E> */ B(TestIn), R(arg0),
                 B(JumpIfFalse), U8(5),
   /*  202 S> */ B(LdaSmi), U8(1),
   /*  262 S> */ B(Return),
-  /*  216 S> */ B(Ldar), R(arg0),
-                B(Star), R(0),
+  /*  216 S> */ B(Nop),
   /*  233 E> */ B(Ldar), R(arg1),
-  /*  222 E> */ B(TestInstanceOf), R(0),
+  /*  222 E> */ B(TestInstanceOf), R(arg0),
                 B(JumpIfFalse), U8(5),
   /*  238 S> */ B(LdaSmi), U8(1),
   /*  262 S> */ B(Return),
   /*  252 S> */ B(LdaZero),
   /*  262 S> */ B(Return),
 ]
 constant pool: [
 ]
 handlers: [
 ]
@@ skipping 23 matching lines @@
   /*   69 S> */ B(LdaSmi), U8(-20),
   /*   85 S> */ B(Return),
                 B(LdaUndefined),
   /*   85 S> */ B(Return),
 ]
 constant pool: [
 ]
 handlers: [
 ]