codegen.c: optimize variable assignments after `OP_MOVE`.
`OP_SETGV`
`OP_SETIV`
`OP_SETCV`
`OP_SETCONST`
@@ -529,6 +529,20 @@ gen_setupvar(codegen_scope *s, uint16_t dst, mrb_sym id)
genop_3(s, OP_SETUPVAR, dst, idx, lv);
}
+static int new_sym(codegen_scope *s, mrb_sym sym);
+
+static void
+gen_setxv(codegen_scope *s, uint8_t op, uint16_t dst, mrb_sym sym)
+{
+ int idx = new_sym(s, sym);
+ struct mrb_insn_data data = mrb_last_insn(s);
+ if (!no_peephole(s) && data.insn == OP_MOVE && data.a == dst) {
+ dst = data.b;
+ s->pc = s->lastpc;
+ }
+ genop_2(s, op, dst, idx);
+}
+
static void
gen_return(codegen_scope *s, uint8_t op, uint16_t src)
{
@@ -1312,8 +1326,7 @@ gen_assignment(codegen_scope *s, node *tree, int sp, int val)
tree = tree->cdr;
switch (type) {
case NODE_GVAR:
- idx = new_sym(s, nsym(tree));
- genop_2(s, OP_SETGV, sp, idx);
+ gen_setxv(s, OP_SETGV, sp, nsym(tree));
break;
case NODE_ARG:
case NODE_LVAR:
@@ -1333,16 +1346,13 @@ gen_assignment(codegen_scope *s, node *tree, int sp, int val)
codegen_error(s, "Can't assign to numbered parameter");
break;
case NODE_IVAR:
- idx = new_sym(s, nsym(tree));
- genop_2(s, OP_SETIV, sp, idx);
+ gen_setxv(s, OP_SETIV, sp, nsym(tree));
break;
case NODE_CVAR:
- idx = new_sym(s, nsym(tree));
- genop_2(s, OP_SETCV, sp, idx);
+ gen_setxv(s, OP_SETCV, sp, nsym(tree));
break;
case NODE_CONST:
- idx = new_sym(s, nsym(tree));
- genop_2(s, OP_SETCONST, sp, idx);
+ gen_setxv(s, OP_SETCONST, sp, nsym(tree));
break;
case NODE_COLON2:
gen_move(s, cursp(), sp, 0);
