TonBERRY/micropython
3
0
Fork 0
Code Pull Requests Activity

py/emit: Remove logic to detect last-emit-was-return-value.

Browse Source 
This optimisation to remove dead code is not as good as it could be.

Signed-off-by: Damien George <damien@micropython.org>
This commit is contained in:
Damien George
2022-06-17 23:06:24 +10:00
parent 0db046b67b
commit e85a096302
5 changed files with 16 additions and 48 deletions
Download Patch File Download Diff File Expand all files Collapse all files

24
py/compile.c
View File

@@ -1330,12 +1330,8 @@ STATIC void compile_if_stmt(compiler_t *comp, mp_parse_node_struct_t *pns) {
goto done;
}
if (
// optimisation: don't jump over non-existent elif/else blocks
!(MP_PARSE_NODE_IS_NULL(pns->nodes[2]) && MP_PARSE_NODE_IS_NULL(pns->nodes[3]))
// optimisation: don't jump if last instruction was return
&& !EMIT(last_emit_was_return_value)
) {
// optimisation: don't jump over non-existent elif/else blocks
if (!(MP_PARSE_NODE_IS_NULL(pns->nodes[2]) && MP_PARSE_NODE_IS_NULL(pns->nodes[3]))) {
// jump over elif/else blocks
EMIT_ARG(jump, l_end);
}
@@ -1362,10 +1358,7 @@ STATIC void compile_if_stmt(compiler_t *comp, mp_parse_node_struct_t *pns) {
goto done;
}
// optimisation: don't jump if last instruction was return
if (!EMIT(last_emit_was_return_value)) {
EMIT_ARG(jump, l_end);
}
EMIT_ARG(jump, l_end);
EMIT_ARG(label_assign, l_fail);
}
}
@@ -1580,9 +1573,7 @@ STATIC void compile_for_stmt(compiler_t *comp, mp_parse_node_struct_t *pns) {
EMIT_ARG(for_iter, pop_label);
c_assign(comp, pns->nodes[0], ASSIGN_STORE); // variable
compile_node(comp, pns->nodes[2]); // body
if (!EMIT(last_emit_was_return_value)) {
EMIT_ARG(jump, continue_label);
}
EMIT_ARG(jump, continue_label);
EMIT_ARG(label_assign, pop_label);
EMIT(for_iter_end);
@@ -3048,11 +3039,8 @@ STATIC bool compile_scope(compiler_t *comp, scope_t *scope, pass_kind_t pass) {
}
compile_node(comp, pns->nodes[3]); // 3 is function body
// emit return if it wasn't the last opcode
if (!EMIT(last_emit_was_return_value)) {
EMIT_ARG(load_const_tok, MP_TOKEN_KW_NONE);
EMIT(return_value);
}
EMIT_ARG(load_const_tok, MP_TOKEN_KW_NONE);
EMIT(return_value);
} else if (scope->kind == SCOPE_LAMBDA) {
assert(MP_PARSE_NODE_IS_STRUCT(scope->pn));
mp_parse_node_struct_t *pns = (mp_parse_node_struct_t *)scope->pn;