> On Aug 17, 2021, at 3:29 AM, Richard Biener <[email protected]> wrote:
>
> 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)
You mean during RTL expansion phase, all SSA_NAMEs are gone already?
>
>> /* 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);
Okay.
>
>>
>> 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
Okay.
>
>> 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);
You mean the following:
tree init = pattern;
If (init_type != AUTO_INIT_PATTERN)
Init = build_zero_cst (var_type);
Or something else?
>
>
> the above should work, as said the RTL expansion part can possibly
> be improved but we can do this as followup as well.
Okay.
Qing
>
>> expand_assignment (lhs, init, false);
>> }
>> }
>>
>> Thanks.
>>
>> Qing
>>
>>
>>
>>
>
> --
> Richard Biener <[email protected]>
> SUSE Software Solutions Germany GmbH, Maxfeldstrasse 5, 90409 Nuernberg,
> Germany; GF: Felix Imendörffer; HRB 36809 (AG Nuernberg)
