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Add optimisation for "for x in range".

This commit is contained in:
Damien 2013-11-06 20:20:49 +00:00
parent 5bf32c3b6b
commit f72fd0e875
1 changed files with 81 additions and 0 deletions
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81
py/compile.c
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@ -1357,7 +1357,88 @@ void compile_while_stmt(compiler_t *comp, py_parse_node_struct_t *pns) {
EMIT(label_assign, break_label);
}
// TODO preload end and step onto stack if they are not constants
// TODO check if step is negative and do opposite test
void compile_for_stmt_optimised_range(compiler_t *comp, py_parse_node_t pn_var, py_parse_node_t pn_start, py_parse_node_t pn_end, py_parse_node_t pn_step, py_parse_node_t pn_body, py_parse_node_t pn_else) {
int old_break_label = comp->break_label;
int old_continue_label = comp->continue_label;
int break_label = comp_next_label(comp);
int continue_label = comp_next_label(comp);
comp->break_label = break_label;
comp->continue_label = continue_label;
int top_label = comp_next_label(comp);
// compile: var = start
compile_node(comp, pn_start);
c_assign(comp, pn_var, ASSIGN_STORE);
EMIT(jump, continue_label);
EMIT(label_assign, top_label);
// compile: var += step
c_assign(comp, pn_var, ASSIGN_AUG_LOAD);
compile_node(comp, pn_step);
EMIT(binary_op, RT_BINARY_OP_INPLACE_ADD);
c_assign(comp, pn_var, ASSIGN_AUG_STORE);
// compile body
compile_node(comp, pn_body);
EMIT(label_assign, continue_label);
// compile: if var < end: goto top
compile_node(comp, pn_var);
compile_node(comp, pn_end);
EMIT(compare_op, RT_COMPARE_OP_LESS);
EMIT(pop_jump_if_true, top_label);
// break/continue apply to outer loop (if any) in the else block
comp->break_label = old_break_label;
comp->continue_label = old_continue_label;
compile_node(comp, pn_else);
EMIT(label_assign, break_label);
}
void compile_for_stmt(compiler_t *comp, py_parse_node_struct_t *pns) {
#if !MICROPY_EMIT_CPYTHON
// this bit optimises: for <x> in range(...), turning it into an explicitly incremented variable
// this is actually slower, but uses no heap memory
// for viper it will be much, much faster
if (PY_PARSE_NODE_IS_STRUCT_KIND(pns->nodes[1], PN_power)) {
py_parse_node_struct_t *pns_it = (py_parse_node_struct_t*)pns->nodes[1];
if (PY_PARSE_NODE_IS_ID(pns_it->nodes[0]) && PY_PARSE_NODE_IS_STRUCT_KIND(pns_it->nodes[1], PN_trailer_paren) && PY_PARSE_NODE_IS_NULL(pns_it->nodes[2])) {
py_parse_node_t pn_range_args = ((py_parse_node_struct_t*)pns_it->nodes[1])->nodes[0];
py_parse_node_t *args;
int n_args = list_get(&pn_range_args, PN_arglist, &args);
if (1 <= n_args && n_args <= 3) {
py_parse_node_t pn_range_start;
py_parse_node_t pn_range_end;
py_parse_node_t pn_range_step;
if (n_args == 1) {
pn_range_start = py_parse_node_new_leaf(PY_PARSE_NODE_SMALL_INT, 0);
pn_range_end = args[0];
pn_range_step = py_parse_node_new_leaf(PY_PARSE_NODE_SMALL_INT, 1);
} else if (n_args == 2) {
pn_range_start = args[0];
pn_range_end = args[1];
pn_range_step = py_parse_node_new_leaf(PY_PARSE_NODE_SMALL_INT, 1);
} else {
pn_range_start = args[0];
pn_range_end = args[1];
pn_range_step = args[2];
}
compile_for_stmt_optimised_range(comp, pns->nodes[0], pn_range_start, pn_range_end, pn_range_step, pns->nodes[2], pns->nodes[3]);
return;
}
}
}
#endif
int old_break_label = comp->break_label;
int old_continue_label = comp->continue_label;