On Tue, 17 Aug 2021, Qing Zhao wrote:
>
>
> > On Aug 17, 2021, at 9:50 AM, Qing Zhao via Gcc-patches
> > <gcc-patches@gcc.gnu.org> wrote:
> >
> >
> >
> >> On Aug 17, 2021, at 3:29 AM, Richard Biener <rguent...@suse.de> 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?
>
> Actually, the lhs could be SSA_NAME here,
>
> Breakpoint 1, expand_DEFERRED_INIT (stmt=0x7fffe96ae348) at
> ../../latest-gcc/gcc/internal-fn.c:3021
> 3021 mark_addressable (lhs);
> (gdb) call debug_tree(lhs)
> <ssa_name 0x7fffe9584e58
> type <real_type 0x7fffe959b2a0 float sizes-gimplified SF
> size <integer_cst 0x7fffe9579f48 constant 32>
> unit-size <integer_cst 0x7fffe9579f60 constant 4>
> align:32 warn_if_not_align:0 symtab:0 alias-set 2 canonical-type
> 0x7fffe959b2a0 precision:32
> pointer_to_this <pointer_type 0x7fffe959b7e0>>
> visited var <var_decl 0x7ffff7ff7bd0 temp1>
> def_stmt temp1_5 = .DEFERRED_INIT (4, 2, 0, &"temp1"[0]);
> version:5>
>
> when I deleted:
>
> if (TREE_CODE (lhs) == SSA_NAME
> lhs = SSA_NAME_VAR (lhs);
but then using SSA_NAME_VAR is broken. I suspect use_register_for_decl
isn't the correct thing to look at. I think we need to look at what
the LHS expanded to if it is a SSA_VAR_P (that includes SSA names
but also plain DECLs but not what we get from VLAs where we'd see
*ptr). So sth like
bool reg_lhs;
if (SSA_VAR_P (lhs))
{
rtx tem = expand_expr (lhs, NULL_RTX, VOIDmode, EXPAND_WRITE);
reg_lhs = !MEM_P (tem);
/* If not MEM_P reg_lhs should be REG_P or SUBREG_P (but maybe
also CONCAT or lowpart...?) */
}
else
{
gcc_assert (is_vla);
reg_lhs = false;
}
if (!reg_lhs)
memset path
else
expand_assignment path
> Many testing cases failed with internal compiler error:
>
> /home/opc/Work/GCC/latest-gcc/gcc/testsuite/c-c++-common/auto-init-3.c:9:9:
> internal compiler error: in expand_expr_addr_expr_1, at expr.c:8437
> 0xe237aa expand_expr_addr_expr_1
> ../../latest-gcc/gcc/expr.c:8437
> 0xe24059 expand_expr_addr_expr
> ../../latest-gcc/gcc/expr.c:8525
> 0xe32b56 expand_expr_real_1(tree_node*, rtx_def*, machine_mode,
> expand_modifier, rtx_def**, bool)
> ../../latest-gcc/gcc/expr.c:11741
> 0xe2da52 expand_expr_real_1(tree_node*, rtx_def*, machine_mode,
> expand_modifier, rtx_def**, bool)
> ../../latest-gcc/gcc/expr.c:10777
> 0xe24706 expand_expr_real(tree_node*, rtx_def*, machine_mode,
> expand_modifier, rtx_def**, bool)
> ../../latest-gcc/gcc/expr.c:8713
> 0xc13f15 expand_expr
> ../../latest-gcc/gcc/expr.h:301
> 0xc17acb get_memory_rtx
> ../../latest-gcc/gcc/builtins.c:1370
> 0xc2223d expand_builtin_memset_args
> ../../latest-gcc/gcc/builtins.c:4102
> 0xc21a20 expand_builtin_memset(tree_node*, rtx_def*, machine_mode)
> ../../latest-gcc/gcc/builtins.c:3886
> 0xfb5c85 expand_DEFERRED_INIT
> ../../latest-gcc/gcc/internal-fn.c:3031
>
>
> So, did I do anything wrong?
>
> Qing
--
Richard Biener <rguent...@suse.de>
SUSE Software Solutions Germany GmbH, Maxfeldstrasse 5, 90409 Nuernberg,
Germany; GF: Felix Imendörffer; HRB 36809 (AG Nuernberg)
