* [PATCH] i386: Make most MD builtins nothrow, leaf [PR112962]
@ 2023-12-13 9:21 Jakub Jelinek
2023-12-20 10:42 ` Patch ping (Re: [PATCH] i386: Make most MD builtins nothrow, leaf [PR112962]) Jakub Jelinek
2023-12-20 10:49 ` [PATCH] i386: Make most MD builtins nothrow, leaf [PR112962] Uros Bizjak
0 siblings, 2 replies; 3+ messages in thread
From: Jakub Jelinek @ 2023-12-13 9:21 UTC (permalink / raw)
To: Uros Bizjak, Hongtao Liu; +Cc: gcc-patches
Hi!
The following patch makes most of x86 MD builtins nothrow,leaf
(like most middle-end builtins are). For -fnon-call-exceptions it
doesn't nothrow, better might be to still add it if the builtins
don't read or write memory and can't raise floating point exceptions,
but we don't have such information readily available, so the patch
uses just !flag_non_call_exceptions for now.
Not sure if we shouldn't have some exceptions for the leaf attribute,
e.g. wonder about EMMS/FEMMS and the various xsave/xrstor etc. builtins,
pedantically none of those builtins do anything that leaf functions
are forbidden to do (having callbacks, calling functions from current TU,
longjump into the current TU), but sometimes non-leaf is also used on
really complex functions to prevent some unwanted optimizations.
That said, haven't run into any problems as is with the patch.
Bootstrapped/regtested on x86_64-linux and i686-linux, ok for trunk?
2023-12-13 Jakub Jelinek <jakub@redhat.com>
PR target/112962
* config/i386/i386-builtins.cc (ix86_builtins): Increase by one
element.
(def_builtin): If not -fnon-call-exceptions, set TREE_NOTHROW on
the builtin FUNCTION_DECL. Add leaf attribute to DECL_ATTRIBUTES.
(ix86_add_new_builtins): Likewise.
--- gcc/config/i386/i386-builtins.cc.jj 2023-10-13 19:34:43.767837029 +0200
+++ gcc/config/i386/i386-builtins.cc 2023-12-12 12:20:50.980071085 +0100
@@ -221,7 +221,7 @@ ix86_get_builtin_func_type (enum ix86_bu
}
/* Table for the ix86 builtin decls. */
-static GTY(()) tree ix86_builtins[(int) IX86_BUILTIN_MAX];
+static GTY(()) tree ix86_builtins[(int) IX86_BUILTIN_MAX + 1];
struct builtin_isa ix86_builtins_isa[(int) IX86_BUILTIN_MAX];
@@ -295,6 +295,12 @@ def_builtin (HOST_WIDE_INT mask, HOST_WI
NULL, NULL_TREE);
ix86_builtins[(int) code] = decl;
ix86_builtins_isa[(int) code].set_and_not_built_p = false;
+ if (!flag_non_call_exceptions)
+ TREE_NOTHROW (decl) = 1;
+ if (ix86_builtins[(int) IX86_BUILTIN_MAX] == NULL_TREE)
+ ix86_builtins[(int) IX86_BUILTIN_MAX]
+ = build_tree_list (get_identifier ("leaf"), NULL_TREE);
+ DECL_ATTRIBUTES (decl) = ix86_builtins[(int) IX86_BUILTIN_MAX];
}
else
{
@@ -393,6 +399,12 @@ ix86_add_new_builtins (HOST_WIDE_INT isa
TREE_READONLY (decl) = 1;
if (ix86_builtins_isa[i].pure_p)
DECL_PURE_P (decl) = 1;
+ if (!flag_non_call_exceptions)
+ TREE_NOTHROW (decl) = 1;
+ if (ix86_builtins[(int) IX86_BUILTIN_MAX] == NULL_TREE)
+ ix86_builtins[(int) IX86_BUILTIN_MAX]
+ = build_tree_list (get_identifier ("leaf"), NULL_TREE);
+ DECL_ATTRIBUTES (decl) = ix86_builtins[(int) IX86_BUILTIN_MAX];
}
}
Jakub
^ permalink raw reply [flat|nested] 3+ messages in thread
* Patch ping (Re: [PATCH] i386: Make most MD builtins nothrow, leaf [PR112962])
2023-12-13 9:21 [PATCH] i386: Make most MD builtins nothrow, leaf [PR112962] Jakub Jelinek
@ 2023-12-20 10:42 ` Jakub Jelinek
2023-12-20 10:49 ` [PATCH] i386: Make most MD builtins nothrow, leaf [PR112962] Uros Bizjak
1 sibling, 0 replies; 3+ messages in thread
From: Jakub Jelinek @ 2023-12-20 10:42 UTC (permalink / raw)
To: Uros Bizjak, Hongtao Liu, gcc-patches
Hi!
On Wed, Dec 13, 2023 at 10:21:43AM +0100, Jakub Jelinek wrote:
> The following patch makes most of x86 MD builtins nothrow,leaf
> (like most middle-end builtins are). For -fnon-call-exceptions it
> doesn't nothrow, better might be to still add it if the builtins
> don't read or write memory and can't raise floating point exceptions,
> but we don't have such information readily available, so the patch
> uses just !flag_non_call_exceptions for now.
> Not sure if we shouldn't have some exceptions for the leaf attribute,
> e.g. wonder about EMMS/FEMMS and the various xsave/xrstor etc. builtins,
> pedantically none of those builtins do anything that leaf functions
> are forbidden to do (having callbacks, calling functions from current TU,
> longjump into the current TU), but sometimes non-leaf is also used on
> really complex functions to prevent some unwanted optimizations.
> That said, haven't run into any problems as is with the patch.
>
> Bootstrapped/regtested on x86_64-linux and i686-linux, ok for trunk?
>
> 2023-12-13 Jakub Jelinek <jakub@redhat.com>
>
> PR target/112962
> * config/i386/i386-builtins.cc (ix86_builtins): Increase by one
> element.
> (def_builtin): If not -fnon-call-exceptions, set TREE_NOTHROW on
> the builtin FUNCTION_DECL. Add leaf attribute to DECL_ATTRIBUTES.
> (ix86_add_new_builtins): Likewise.
I'd like to ping this patch. Bootstrapped/regtested fine again last night.
Jakub
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [PATCH] i386: Make most MD builtins nothrow, leaf [PR112962]
2023-12-13 9:21 [PATCH] i386: Make most MD builtins nothrow, leaf [PR112962] Jakub Jelinek
2023-12-20 10:42 ` Patch ping (Re: [PATCH] i386: Make most MD builtins nothrow, leaf [PR112962]) Jakub Jelinek
@ 2023-12-20 10:49 ` Uros Bizjak
1 sibling, 0 replies; 3+ messages in thread
From: Uros Bizjak @ 2023-12-20 10:49 UTC (permalink / raw)
To: Jakub Jelinek; +Cc: Hongtao Liu, gcc-patches
On Wed, Dec 13, 2023 at 10:21 AM Jakub Jelinek <jakub@redhat.com> wrote:
>
> Hi!
>
> The following patch makes most of x86 MD builtins nothrow,leaf
> (like most middle-end builtins are). For -fnon-call-exceptions it
> doesn't nothrow, better might be to still add it if the builtins
> don't read or write memory and can't raise floating point exceptions,
> but we don't have such information readily available, so the patch
> uses just !flag_non_call_exceptions for now.
> Not sure if we shouldn't have some exceptions for the leaf attribute,
> e.g. wonder about EMMS/FEMMS and the various xsave/xrstor etc. builtins,
> pedantically none of those builtins do anything that leaf functions
> are forbidden to do (having callbacks, calling functions from current TU,
> longjump into the current TU), but sometimes non-leaf is also used on
> really complex functions to prevent some unwanted optimizations.
> That said, haven't run into any problems as is with the patch.
>
> Bootstrapped/regtested on x86_64-linux and i686-linux, ok for trunk?
>
> 2023-12-13 Jakub Jelinek <jakub@redhat.com>
>
> PR target/112962
> * config/i386/i386-builtins.cc (ix86_builtins): Increase by one
> element.
> (def_builtin): If not -fnon-call-exceptions, set TREE_NOTHROW on
> the builtin FUNCTION_DECL. Add leaf attribute to DECL_ATTRIBUTES.
> (ix86_add_new_builtins): Likewise.
LGTM.
Thanks,
Uros.
>
> --- gcc/config/i386/i386-builtins.cc.jj 2023-10-13 19:34:43.767837029 +0200
> +++ gcc/config/i386/i386-builtins.cc 2023-12-12 12:20:50.980071085 +0100
> @@ -221,7 +221,7 @@ ix86_get_builtin_func_type (enum ix86_bu
> }
>
> /* Table for the ix86 builtin decls. */
> -static GTY(()) tree ix86_builtins[(int) IX86_BUILTIN_MAX];
> +static GTY(()) tree ix86_builtins[(int) IX86_BUILTIN_MAX + 1];
>
> struct builtin_isa ix86_builtins_isa[(int) IX86_BUILTIN_MAX];
>
> @@ -295,6 +295,12 @@ def_builtin (HOST_WIDE_INT mask, HOST_WI
> NULL, NULL_TREE);
> ix86_builtins[(int) code] = decl;
> ix86_builtins_isa[(int) code].set_and_not_built_p = false;
> + if (!flag_non_call_exceptions)
> + TREE_NOTHROW (decl) = 1;
> + if (ix86_builtins[(int) IX86_BUILTIN_MAX] == NULL_TREE)
> + ix86_builtins[(int) IX86_BUILTIN_MAX]
> + = build_tree_list (get_identifier ("leaf"), NULL_TREE);
> + DECL_ATTRIBUTES (decl) = ix86_builtins[(int) IX86_BUILTIN_MAX];
> }
> else
> {
> @@ -393,6 +399,12 @@ ix86_add_new_builtins (HOST_WIDE_INT isa
> TREE_READONLY (decl) = 1;
> if (ix86_builtins_isa[i].pure_p)
> DECL_PURE_P (decl) = 1;
> + if (!flag_non_call_exceptions)
> + TREE_NOTHROW (decl) = 1;
> + if (ix86_builtins[(int) IX86_BUILTIN_MAX] == NULL_TREE)
> + ix86_builtins[(int) IX86_BUILTIN_MAX]
> + = build_tree_list (get_identifier ("leaf"), NULL_TREE);
> + DECL_ATTRIBUTES (decl) = ix86_builtins[(int) IX86_BUILTIN_MAX];
> }
> }
>
>
> Jakub
>
^ permalink raw reply [flat|nested] 3+ messages in thread
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2023-12-13 9:21 [PATCH] i386: Make most MD builtins nothrow, leaf [PR112962] Jakub Jelinek
2023-12-20 10:42 ` Patch ping (Re: [PATCH] i386: Make most MD builtins nothrow, leaf [PR112962]) Jakub Jelinek
2023-12-20 10:49 ` [PATCH] i386: Make most MD builtins nothrow, leaf [PR112962] Uros Bizjak
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