On Fri, 11 Feb 2022, Jakub Jelinek wrote:
> Hi!
>
> When looking at __builtin_clear_padding today, I've noticed that
> it is quite wasteful to extend the original user one argument to 3,
> 2 is enough. We need to encode the original type of the first argument
> because pointer conversions are useless in GIMPLE, and we need to record
> a boolean whether it is for -ftrivial-auto-var-init=* or not.
> But for recording the type we don't need the value (we've always used
> zero) and for recording the boolean we don't need the type (we've always
> used integer_type_node).
> So, this patch merges the two into one.
>
> Ok for trunk if it passes full bootstrap/regtest?
OK.
Thanks,
Richard.
> 2022-02-11 Jakub Jelinek <ja...@redhat.com>
>
> * tree.cc (build_common_builtin_nodes): Fix up formatting in
> __builtin_clear_padding decl creation.
> * gimplify.cc (gimple_add_padding_init_for_auto_var): Encode
> for_auto_init in the value of 2nd BUILT_IN_CLEAR_PADDING
> argument rather than in 3rd argument.
> (gimplify_call_expr): Likewise. Fix up comment formatting.
> * gimple-fold.cc (gimple_fold_builtin_clear_padding): Expect
> 2 arguments instead of 3, take for_auto_init from the value
> of 2nd argument.
>
> --- gcc/tree.cc.jj 2022-02-11 00:19:22.436063200 +0100
> +++ gcc/tree.cc 2022-02-11 12:15:00.929134203 +0100
> @@ -9520,7 +9520,7 @@ build_common_builtin_nodes (void)
> local_define_builtin ("__builtin_clear_padding", ftype,
> BUILT_IN_CLEAR_PADDING,
> "__builtin_clear_padding",
> - ECF_LEAF | ECF_NOTHROW);
> + ECF_LEAF | ECF_NOTHROW);
> }
>
> if (!builtin_decl_explicit_p (BUILT_IN_UNREACHABLE)
> --- gcc/gimplify.cc.jj 2022-02-11 00:19:22.305064981 +0100
> +++ gcc/gimplify.cc 2022-02-11 12:17:22.679180223 +0100
> @@ -1804,7 +1804,6 @@ gimple_add_padding_init_for_auto_var (tr
> gimple_seq *seq_p)
> {
> tree addr_of_decl = NULL_TREE;
> - bool for_auto_init = true;
> tree fn = builtin_decl_explicit (BUILT_IN_CLEAR_PADDING);
>
> if (is_vla)
> @@ -1821,11 +1820,8 @@ gimple_add_padding_init_for_auto_var (tr
> addr_of_decl = build_fold_addr_expr (decl);
> }
>
> - gimple *call = gimple_build_call (fn,
> - 3, addr_of_decl,
> - build_zero_cst (TREE_TYPE (addr_of_decl)),
> - build_int_cst (integer_type_node,
> - (int) for_auto_init));
> + gimple *call = gimple_build_call (fn, 2, addr_of_decl,
> + build_one_cst (TREE_TYPE (addr_of_decl)));
> gimplify_seq_add_stmt (seq_p, call);
> }
>
> @@ -3536,15 +3532,12 @@ gimplify_call_expr (tree *expr_p, gimple
> {
> /* Remember the original type of the argument in an internal
> dummy second argument, as in GIMPLE pointer conversions are
> - useless. also mark this call as not for automatic initialization
> - in the internal dummy third argument. */
> + useless. Also mark this call as not for automatic
> + initialization in the internal dummy third argument. */
> p = CALL_EXPR_ARG (*expr_p, 0);
> - bool for_auto_init = false;
> *expr_p
> - = build_call_expr_loc (EXPR_LOCATION (*expr_p), fndecl, 3, p,
> - build_zero_cst (TREE_TYPE (p)),
> - build_int_cst (integer_type_node,
> - (int) for_auto_init));
> + = build_call_expr_loc (EXPR_LOCATION (*expr_p), fndecl, 2, p,
> + build_zero_cst (TREE_TYPE (p)));
> return GS_OK;
> }
> break;
> --- gcc/gimple-fold.cc.jj 2022-02-11 00:18:54.799439055 +0100
> +++ gcc/gimple-fold.cc 2022-02-11 12:13:27.869417000 +0100
> @@ -4879,10 +4879,10 @@ gimple_fold_builtin_clear_padding (gimpl
> gcc_assert (gimple_call_num_args (stmt) == 3);
> tree ptr = gimple_call_arg (stmt, 0);
> tree typearg = gimple_call_arg (stmt, 1);
> - /* the 3rd argument of __builtin_clear_padding is to distinguish whether
> - this call is made by the user or by the compiler for automatic variable
> - initialization. */
> - bool for_auto_init = (bool) TREE_INT_CST_LOW (gimple_call_arg (stmt, 2));
> + /* The 2nd argument of __builtin_clear_padding's value is used to
> + distinguish whether this call is made by the user or by the compiler
> + for automatic variable initialization. */
> + bool for_auto_init = (bool) TREE_INT_CST_LOW (typearg);
> tree type = TREE_TYPE (TREE_TYPE (typearg));
> location_t loc = gimple_location (stmt);
> clear_padding_struct buf;
>
> Jakub
>
>
--
Richard Biener <rguent...@suse.de>
SUSE Software Solutions Germany GmbH, Maxfeldstrasse 5, 90409 Nuernberg,
Germany; GF: Ivo Totev; HRB 36809 (AG Nuernberg)
