On Mon, 16 Aug 2021, Qing Zhao wrote:
> My current code for expand_DEFERRED_INIT is like the following, could you
> check and see whether there is any issue for it:
>
> #define INIT_PATTERN_VALUE 0xFE
> static void
> expand_DEFERRED_INIT (internal_fn, gcall *stmt)
> {
> tree lhs = gimple_call_lhs (stmt);
> tree var_size = gimple_call_arg (stmt, 0);
> enum auto_init_type init_type
> = (enum auto_init_type) TREE_INT_CST_LOW (gimple_call_arg (stmt, 1));
> bool is_vla = (bool) TREE_INT_CST_LOW (gimple_call_arg (stmt, 2));
>
> tree var_type = TREE_TYPE (lhs);
> gcc_assert (init_type > AUTO_INIT_UNINITIALIZED);
>
> if (is_vla || (!use_register_for_decl (lhs)))
> {
> if (TREE_CODE (lhs) == SSA_NAME)
> lhs = SSA_NAME_VAR (lhs);
this should not be necessary (in fact you shouldn't see a SSA_NAME
here, if you do then using SSA_NAME_VAR is wrong)
> /* If this is a VLA or the variable is not in register,
> expand to a memset to initialize it. */
> tree var_addr = NULL_TREE;
> if (is_vla)
> var_addr = TREE_OPERAND (lhs, 0);
> else
> {
> TREE_ADDRESSABLE (lhs) = 1;
> var_addr = build_fold_addr_expr (lhs);
> }
use, independent of is_vla
mark_addressable (lhs);
var_addr = build_fold_addr_expr (lhs);
>
> tree value = (init_type == AUTO_INIT_PATTERN) ?
> build_int_cst (unsigned_char_type_node,
> INIT_PATTERN_VALUE) :
> build_zero_cst (unsigned_char_type_node);
since memset has an integer argument for the value use
integer_zero_node for the zero case and build_int_cst (integer_type_node,
...) for the pattern case
> tree m_call = build_call_expr (builtin_decl_implicit (BUILT_IN_MEMSET),
> 3, var_addr, value, var_size);
> /* Expand this memset call. */
> expand_builtin_memset (m_call, NULL_RTX, TYPE_MODE (var_type));
> }
> else
> {
> /* If this variable is in a register, use expand_assignment might
> generate better code. */
> tree pattern = NULL_TREE;
> unsigned HOST_WIDE_INT total_bytes
> = tree_to_uhwi (TYPE_SIZE_UNIT (var_type));
>
> if (init_type == AUTO_INIT_PATTERN)
> {
> if (can_native_interpret_type_p (var_type))
> {
> unsigned char *buf = (unsigned char *) xmalloc (total_bytes);
> memset (buf, INIT_PATTERN_VALUE, total_bytes);
> pattern = native_interpret_expr (var_type, buf, total_bytes);
> gcc_assert (pattern);
> }
> else
> {
> tree index_type = build_index_type (size_int (total_bytes - 1));
> tree array_type = build_array_type (unsigned_char_type_node,
> index_type);
> tree element = build_int_cst (unsigned_char_type_node,
> INIT_PATTERN_VALUE);
> vec<constructor_elt, va_gc> *elts = NULL;
> for (unsigned int i = 0; i < total_bytes; i++)
> CONSTRUCTOR_APPEND_ELT (elts, NULL_TREE, element);
> pattern = build_constructor (array_type, elts);
> pattern = build1 (VIEW_CONVERT_EXPR, var_type, pattern);
> }
> }
>
> tree init = (init_type == AUTO_INIT_PATTERN) ?
> pattern :
> build_zero_cst (var_type);
maybe conditionally initialize init instead of pattern and init?
Thus replace pattern by init and do
else
init = build_zero_cst (var_type);
the above should work, as said the RTL expansion part can possibly
be improved but we can do this as followup as well.
> expand_assignment (lhs, init, false);
> }
> }
>
> Thanks.
>
> Qing
>
>
>
>
--
Richard Biener <rguent...@suse.de>
SUSE Software Solutions Germany GmbH, Maxfeldstrasse 5, 90409 Nuernberg,
Germany; GF: Felix Imendörffer; HRB 36809 (AG Nuernberg)
