https://gcc.gnu.org/bugzilla/show_bug.cgi?id=91270
--- Comment #6 from Martin Liška <marxin at gcc dot gnu.org> ---
(In reply to Martin Liška from comment #5)
> I've got a patch candidate:
>
> diff --git a/gcc/tree-ssa-dce.c b/gcc/tree-ssa-dce.c
> index cf507fa0453..bdaad09ef35 100644
> --- a/gcc/tree-ssa-dce.c
> +++ b/gcc/tree-ssa-dce.c
> @@ -1294,6 +1294,21 @@ eliminate_unnecessary_stmts (void)
> && !gimple_plf (def_stmt, STMT_NECESSARY))
> gimple_set_plf (stmt, STMT_NECESSARY, false);
> }
> +
> + /* Delete operator has 2 arguments, where the second argument is
> + size of the deallocated memory. */
> + if (is_gimple_call (stmt)
> + && gimple_call_operator_delete_p (as_a <gcall *> (stmt)))
> + {
> + tree ptr = gimple_call_arg (stmt, 1);
> + if (TREE_CODE (ptr) == SSA_NAME)
> + {
> + gimple *def_stmt = SSA_NAME_DEF_STMT (ptr);
> + if (!gimple_nop_p (def_stmt)
> + && !gimple_plf (def_stmt, STMT_NECESSARY))
> + gimple_set_plf (stmt, STMT_NECESSARY, false);
> + }
> + }
> }
>
> /* If GSI is not necessary then remove it. */
>
> I'll finish it tomorrow morning and send it to mailing list.
This patch will be better:
diff --git a/gcc/tree-ssa-dce.c b/gcc/tree-ssa-dce.c
index cf507fa0453..04338a67181 100644
--- a/gcc/tree-ssa-dce.c
+++ b/gcc/tree-ssa-dce.c
@@ -1294,6 +1294,20 @@ eliminate_unnecessary_stmts (void)
&& !gimple_plf (def_stmt, STMT_NECESSARY))
gimple_set_plf (stmt, STMT_NECESSARY, false);
}
+
+ /* Some delete operators have 2 arguments, where the second
argument is
+ size of the deallocated memory. */
+ if (gimple_call_num_args (stmt) == 2)
+ {
+ tree ptr = gimple_call_arg (stmt, 1);
+ if (TREE_CODE (ptr) == SSA_NAME)
+ {
+ gimple *def_stmt = SSA_NAME_DEF_STMT (ptr);
+ if (!gimple_nop_p (def_stmt)
+ && !gimple_plf (def_stmt, STMT_NECESSARY))
+ gimple_set_plf (stmt, STMT_NECESSARY, false);
+ }
+ }
}
/* If GSI is not necessary then remove it. */
