py: remove "if (0)" and "if (false)" branches.

Prior to this commit, building the unix port with `DEBUG=1` and
`-finstrument-functions` the compilation would fail with an error like
"control reaches end of non-void function".  This change fixes this by
removing the problematic "if (0)" branches.  Not all branches affect
compilation, but they are all removed for consistency.

py/compile.c

@@ -3457,12 +3457,12 @@ mp_raw_code_t *mp_compile_to_raw_code(mp_parse_tree_t *parse_tree, qstr source_f
     #endif
     uint max_num_labels = 0;
     for (scope_t *s = comp->scope_head; s != NULL && comp->compile_error == MP_OBJ_NULL; s = s->next) {
-        if (false) {
         #if MICROPY_EMIT_INLINE_ASM
-        } else if (s->emit_options == MP_EMIT_OPT_ASM) {
+        if (s->emit_options == MP_EMIT_OPT_ASM) {
             compile_scope_inline_asm(comp, s, MP_PASS_SCOPE);
+        } else
         #endif
-        } else {
+        {
             compile_scope(comp, s, MP_PASS_SCOPE);
 
             // Check if any implicitly declared variables should be closed over
@@ -3493,11 +3493,8 @@ mp_raw_code_t *mp_compile_to_raw_code(mp_parse_tree_t *parse_tree, qstr source_f
     emit_t *emit_native = NULL;
 #endif
     for (scope_t *s = comp->scope_head; s != NULL && comp->compile_error == MP_OBJ_NULL; s = s->next) {
-        if (false) {
-            // dummy
-
         #if MICROPY_EMIT_INLINE_ASM
-        } else if (s->emit_options == MP_EMIT_OPT_ASM) {
+        if (s->emit_options == MP_EMIT_OPT_ASM) {
             // inline assembly
             if (comp->emit_inline_asm == NULL) {
                 comp->emit_inline_asm = ASM_EMITTER(new)(max_num_labels);
@@ -3519,9 +3516,9 @@ mp_raw_code_t *mp_compile_to_raw_code(mp_parse_tree_t *parse_tree, qstr source_f
             if (comp->compile_error == MP_OBJ_NULL) {
                 compile_scope_inline_asm(comp, s, MP_PASS_EMIT);
             }
+        } else
         #endif
-
+        {
-        } else {
 
             // choose the emit type
 

py/emitnative.c

@@ -2227,17 +2227,16 @@ STATIC void emit_native_binary_op(emit_t *emit, mp_binary_op_t op) {
         int reg_rhs = REG_ARG_3;
         emit_pre_pop_reg_flexible(emit, &vtype_rhs, &reg_rhs, REG_RET, REG_ARG_2);
         emit_pre_pop_reg(emit, &vtype_lhs, REG_ARG_2);
-        if (0) {
-            // dummy
         #if !(N_X64 || N_X86)
-        } else if (op == MP_BINARY_OP_LSHIFT) {
+        if (op == MP_BINARY_OP_LSHIFT) {
             ASM_LSL_REG_REG(emit->as, REG_ARG_2, reg_rhs);
             emit_post_push_reg(emit, VTYPE_INT, REG_ARG_2);
         } else if (op == MP_BINARY_OP_RSHIFT) {
             ASM_ASR_REG_REG(emit->as, REG_ARG_2, reg_rhs);
             emit_post_push_reg(emit, VTYPE_INT, REG_ARG_2);
+        } else
         #endif
-        } else if (op == MP_BINARY_OP_OR) {
+        if (op == MP_BINARY_OP_OR) {
             ASM_OR_REG_REG(emit->as, REG_ARG_2, reg_rhs);
             emit_post_push_reg(emit, VTYPE_INT, REG_ARG_2);
         } else if (op == MP_BINARY_OP_XOR) {

py/objarray.c

@@ -375,9 +375,8 @@ STATIC mp_obj_t array_subscr(mp_obj_t self_in, mp_obj_t index_in, mp_obj_t value
         return MP_OBJ_NULL; // op not supported
     } else {
         mp_obj_array_t *o = MP_OBJ_TO_PTR(self_in);
-        if (0) {
 #if MICROPY_PY_BUILTINS_SLICE
-        } else if (mp_obj_is_type(index_in, &mp_type_slice)) {
+        if (mp_obj_is_type(index_in, &mp_type_slice)) {
             mp_bound_slice_t slice;
             if (!mp_seq_get_fast_slice_indexes(o->len, index_in, &slice)) {
                 mp_raise_NotImplementedError("only slices with step=1 (aka None) are supported");
@@ -456,22 +455,22 @@ STATIC mp_obj_t array_subscr(mp_obj_t self_in, mp_obj_t index_in, mp_obj_t value
             mp_obj_array_t *res;
             size_t sz = mp_binary_get_size('@', o->typecode & TYPECODE_MASK, NULL);
             assert(sz > 0);
-            if (0) {
-                // dummy
             #if MICROPY_PY_BUILTINS_MEMORYVIEW
-            } else if (o->base.type == &mp_type_memoryview) {
+            if (o->base.type == &mp_type_memoryview) {
                 res = m_new_obj(mp_obj_array_t);
                 *res = *o;
                 res->memview_offset += slice.start;
                 res->len = slice.stop - slice.start;
+            } else
             #endif
-            } else {
+            {
                 res = array_new(o->typecode, slice.stop - slice.start);
                 memcpy(res->items, (uint8_t*)o->items + slice.start * sz, (slice.stop - slice.start) * sz);
             }
             return MP_OBJ_FROM_PTR(res);
+        } else
 #endif
-        } else {
+        {
             size_t index = mp_get_index(o->base.type, o->len, index_in, false);
             #if MICROPY_PY_BUILTINS_MEMORYVIEW
             if (o->base.type == &mp_type_memoryview) {

py/objfun.c

@@ -458,13 +458,13 @@ STATIC mp_uint_t convert_obj_for_inline_asm(mp_obj_t obj) {
         return (mp_uint_t)mp_obj_str_get_data(obj, &l);
     } else {
         mp_obj_type_t *type = mp_obj_get_type(obj);
-        if (0) {
 #if MICROPY_PY_BUILTINS_FLOAT
-        } else if (type == &mp_type_float) {
+        if (type == &mp_type_float) {
             // convert float to int (could also pass in float registers)
             return (mp_int_t)mp_obj_float_get(obj);
+        } else
 #endif
-        } else if (type == &mp_type_tuple || type == &mp_type_list) {
+        if (type == &mp_type_tuple || type == &mp_type_list) {
             // pointer to start of tuple (could pass length, but then could use len(x) for that)
             size_t len;
             mp_obj_t *items;

py/objint_mpz.c

@@ -194,18 +194,18 @@ mp_obj_t mp_obj_int_binary_op(mp_binary_op_t op, mp_obj_t lhs_in, mp_obj_t rhs_i
         return mp_obj_int_binary_op_extra_cases(op, lhs_in, rhs_in);
     }
 
-    if (0) {
 #if MICROPY_PY_BUILTINS_FLOAT
-    } else if (op == MP_BINARY_OP_TRUE_DIVIDE || op == MP_BINARY_OP_INPLACE_TRUE_DIVIDE) {
+    if (op == MP_BINARY_OP_TRUE_DIVIDE || op == MP_BINARY_OP_INPLACE_TRUE_DIVIDE) {
         if (mpz_is_zero(zrhs)) {
             goto zero_division_error;
         }
         mp_float_t flhs = mpz_as_float(zlhs);
         mp_float_t frhs = mpz_as_float(zrhs);
         return mp_obj_new_float(flhs / frhs);
+    } else
 #endif
 
-    } else if (op >= MP_BINARY_OP_INPLACE_OR && op < MP_BINARY_OP_CONTAINS) {
+    if (op >= MP_BINARY_OP_INPLACE_OR && op < MP_BINARY_OP_CONTAINS) {
         mp_obj_int_t *res = mp_obj_int_new_mpz();
 
         switch (op) {

py/runtime.c

@@ -1049,14 +1049,13 @@ void mp_load_method_maybe(mp_obj_t obj, qstr attr, mp_obj_t *dest) {
     mp_obj_type_t *type = mp_obj_get_type(obj);
 
     // look for built-in names
-    if (0) {
 #if MICROPY_CPYTHON_COMPAT
-    } else if (attr == MP_QSTR___class__) {
+    if (attr == MP_QSTR___class__) {
         // a.__class__ is equivalent to type(a)
         dest[0] = MP_OBJ_FROM_PTR(type);
+    } else
 #endif
-
+    if (attr == MP_QSTR___next__ && type->iternext != NULL) {
-    } else if (attr == MP_QSTR___next__ && type->iternext != NULL) {
         dest[0] = MP_OBJ_FROM_PTR(&mp_builtin_next_obj);
         dest[1] = obj;