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

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

Signed-off-by: Damien George <damien@micropython.org>

1 files changed, 1 insertions, 14 deletions

diff --git a/py/emitnative.c b/py/emitnative.c
index 6683ea420..5b695a22a 100644
--- a/py/emitnative.c
+++ b/py/emitnative.c
@@ -276,8 +276,6 @@ struct _emit_t {
     uint16_t n_info;
     uint16_t n_cell;
 
-    bool last_emit_was_return_value;
-
     scope_t *scope;
 
     ASM_T *as;
@@ -370,7 +368,6 @@ STATIC void emit_native_start_pass(emit_t *emit, pass_kind_t pass, scope_t *scop
     emit->pass = pass;
     emit->do_viper_types = scope->emit_options == MP_EMIT_OPT_VIPER;
     emit->stack_size = 0;
-    emit->last_emit_was_return_value = false;
     emit->scope = scope;
 
     // allocate memory for keeping track of the types of locals
@@ -733,10 +730,6 @@ STATIC bool emit_native_end_pass(emit_t *emit) {
     return true;
 }
 
-STATIC bool emit_native_last_emit_was_return_value(emit_t *emit) {
-    return emit->last_emit_was_return_value;
-}
-
 STATIC void ensure_extra_stack(emit_t *emit, size_t delta) {
     if (emit->stack_size + delta > emit->stack_info_alloc) {
         size_t new_alloc = (emit->stack_size + delta + 8) & ~3;
@@ -793,7 +786,7 @@ STATIC void emit_native_set_source_line(emit_t *emit, mp_uint_t source_line) {
 
 // this must be called at start of emit functions
 STATIC void emit_native_pre(emit_t *emit) {
-    emit->last_emit_was_return_value = false;
+    (void)emit;
 }
 
 // depth==0 is top, depth==1 is before top, etc
@@ -917,7 +910,6 @@ STATIC void emit_fold_stack_top(emit_t *emit, int reg_dest) {
 // If stacked value is in a register and the register is not r1 or r2, then
 // *reg_dest is set to that register.  Otherwise the value is put in *reg_dest.
 STATIC void emit_pre_pop_reg_flexible(emit_t *emit, vtype_kind_t *vtype, int *reg_dest, int not_r1, int not_r2) {
-    emit->last_emit_was_return_value = false;
     stack_info_t *si = peek_stack(emit, 0);
     if (si->kind == STACK_REG && si->data.u_reg != not_r1 && si->data.u_reg != not_r2) {
         *vtype = si->vtype;
@@ -930,12 +922,10 @@ STATIC void emit_pre_pop_reg_flexible(emit_t *emit, vtype_kind_t *vtype, int *re
 }
 
 STATIC void emit_pre_pop_discard(emit_t *emit) {
-    emit->last_emit_was_return_value = false;
     adjust_stack(emit, -1);
 }
 
 STATIC void emit_pre_pop_reg(emit_t *emit, vtype_kind_t *vtype, int reg_dest) {
-    emit->last_emit_was_return_value = false;
     emit_access_stack(emit, 1, vtype, reg_dest);
     adjust_stack(emit, -1);
 }
@@ -2771,7 +2761,6 @@ STATIC void emit_native_return_value(emit_t *emit) {
 
         // Do the unwinding jump to get to the return handler
         emit_native_unwind_jump(emit, emit->exit_label, emit->exc_stack_size);
-        emit->last_emit_was_return_value = true;
         return;
     }
 
@@ -2809,7 +2798,6 @@ STATIC void emit_native_return_value(emit_t *emit) {
         ASM_MOV_LOCAL_REG(emit->as, LOCAL_IDX_RET_VAL(emit), REG_PARENT_RET);
     }
     emit_native_unwind_jump(emit, emit->exit_label, emit->exc_stack_size);
-    emit->last_emit_was_return_value = true;
 }
 
 STATIC void emit_native_raise_varargs(emit_t *emit, mp_uint_t n_args) {
@@ -2928,7 +2916,6 @@ const emit_method_table_t EXPORT_FUN(method_table) = {
 
     emit_native_start_pass,
     emit_native_end_pass,
-    emit_native_last_emit_was_return_value,
     emit_native_adjust_stack_size,
     emit_native_set_source_line,