On Tue, Jun 27, 2023 at 9:16 AM Julian Waters <tanksherma...@gmail.com> wrote:
>
> Perhaps this only affects compilation when GIMPLE isn't being used?
The only time GIMPLE is not used is if you supply -fsyntax-only so ...
Thanks,
Andrew
>
> On Wed, Jun 28, 2023 at 12:15 AM Julian Waters <tanksherma...@gmail.com>
> wrote:
>>
>> Hi Andrew,
>>
>> That can't be right, on my system a test of asm vs asm volatile with -O3 and
>> -flto=auto yields very different results, with only the latter being
>> correct. The patch fixed it and caused gcc to emit correct assembly
>>
>> best regards,
>> Julian
>>
>> On Wed, Jun 28, 2023 at 12:08 AM Andrew Pinski <pins...@gmail.com> wrote:
>>>
>>> On Tue, Jun 27, 2023 at 9:03 AM Julian Waters via Gcc <gcc@gcc.gnu.org>
>>> wrote:
>>> >
>>> > gcc's documentatation mentions that all basic asm blocks are always
>>> > volatile,
>>> > yet the parser fails to account for this by only ever setting
>>> > volatile_p to true
>>> > if the volatile qualifier is found. This patch fixes this by adding a
>>> > special case check for extended_p before finish_asm_statement is called
>>>
>>> The patch which are you doing will not change the behavior of GCC as
>>> GCC already treats them as volatile later on.
>>> non-extended inline-asm has no outputs so the following code in the
>>> gimplifier will kick in and turn the gimple statement into volatile:
>>> gimple_asm_set_volatile (stmt, ASM_VOLATILE_P (expr) || noutputs ==
>>> 0);
>>>
>>> (note I am about to push a patch which changes the condition slightly
>>> to have `asm goto` as volatile).
>>>
>>> Thanks,
>>> Andrew
>>>
>>> >
>>> > From 3094be39e3e65a6a638f05fafd858b89fefde6b5 Mon Sep 17 00:00:00 2001
>>> > From: TheShermanTanker <tanksherma...@gmail.com>
>>> > Date: Tue, 27 Jun 2023 23:56:38 +0800
>>> > Subject: [PATCH] asm not using extended syntax should always be volatile
>>> >
>>> > ---
>>> > gcc/cp/parser.cc | 3 +++
>>> > 1 file changed, 3 insertions(+)
>>> >
>>> > diff --git a/gcc/cp/parser.cc b/gcc/cp/parser.cc
>>> > index a6341b9..ef3d06a 100644
>>> > --- a/gcc/cp/parser.cc
>>> > +++ b/gcc/cp/parser.cc
>>> > @@ -22355,6 +22355,9 @@ cp_parser_asm_definition (cp_parser* parser)
>>> > /* Create the ASM_EXPR. */
>>> > if (parser->in_function_body)
>>> > {
>>> > + if (!extended_p) {
>>> > + volatile_p = true;
>>> > + }
>>> > asm_stmt = finish_asm_stmt (asm_loc, volatile_p, string, outputs,
>>> > inputs, clobbers, labels, inline_p);
>>> > /* If the extended syntax was not used, mark the ASM_EXPR. */
>>> > --
>>> > 2.35.1.windows.2
