From: Segher Boessenkool <segher@kernel.crashing.org>
To: gcc-patches@gcc.gnu.org, jakub@redhat.com,
Joseph Myers <joseph@codesourcery.com>,
jason@redhat.com, nathan@acm.org, polacek@redhat.com,
richard.sandiford@arm.com
Subject: Re: [PATCH 2/2] asm inline
Date: Thu, 06 Dec 2018 03:03:00 -0000 [thread overview]
Message-ID: <20181205233201.GW3803@gate.crashing.org> (raw)
In-Reply-To: <87a7ll8g2g.fsf@arm.com>
Hi!
On Tue, Dec 04, 2018 at 03:30:47PM +0000, Richard Sandiford wrote:
> Segher Boessenkool <segher@kernel.crashing.org> writes:
> Hmm, so we allow top-level "asm volatile" in C++ but not C?
Apparently. Evert top-level asm is effectively volatile, so this doesn't
really matter; but should we try to resolve the difference?
> Probably worth having tests to show that we (intentionally) don't
> allow top-level "asm inline".
Okay, I'll do this separately.
> > --- a/gcc/doc/extend.texi
> > +++ b/gcc/doc/extend.texi
> > @@ -8382,6 +8382,10 @@ various @option{-std} options, use @code{__asm__} instead of
> > @item volatile
> > The optional @code{volatile} qualifier has no effect.
> > All basic @code{asm} blocks are implicitly volatile.
> > +
> > +@item inline
> > +If you use the @code{inline} qualifier, then for inlining purposes the size
> > +of the asm is taken as the smallest size possible (@pxref{Size of an asm}).
> > @end table
> >
> > @subsubheading Parameters
>
> You need to update the syntax above too, which currently reads:
>
> @example
> asm @r{[} volatile @r{]} ( @var{AssemblerInstructions} )
> @end example
That was modified in patch 1?
@example
asm @var{asm-qualifiers} ( @var{AssemblerInstructions} )
@end example
> > +/* Return true ASM_STMT ASM_STMT is an asm statement marked inline. */
> > +
> > +static inline bool
> > +gimple_asm_inline_p (const gasm *asm_stmt)
> > +{
> > + return (asm_stmt->subcode & GF_ASM_INLINE) != 0;
> > +}
>
> Return true if ASM_STMT is ...
Heh, I copied this from the "volatile" one above. I'll fix that one, too.
> (Or "Return true if asm statement ASM_STMT is marked inline", since gasm
> forces it to be an asm statement.)
Yup, same deal.
> > diff --git a/gcc/tree-inline.c b/gcc/tree-inline.c
> > index 5aa782b..7e9ed99 100644
> > --- a/gcc/tree-inline.c
> > +++ b/gcc/tree-inline.c
> > @@ -4109,6 +4109,9 @@ estimate_num_insns (gimple *stmt, eni_weights *weights)
> > with very long asm statements. */
> > if (count > 1000)
> > count = 1000;
> > + /* If this asm is asm inline, count anything as minimum size. */
> > + if (gimple_asm_inline_p (as_a <gasm *> (stmt)))
> > + count = !!count;
>
> FWIW, since Marc found it confusing too... I think MIN (count, 1) would
> show the intent more clearerly. But that's just personal preference,
> no need to change.
MIN is a nice way to say it, thanks! Better than "!!" or "!= 0" here.
Thanks for the review, I'm committing it with the changes above (later
today, after a final bootstrap),
Segher
next prev parent reply other threads:[~2018-12-06 3:03 UTC|newest]
Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-12-02 16:38 [PATCH v2 0/2] asm qualifiers (PR55681) and " Segher Boessenkool
2018-12-02 16:39 ` [PATCH 1/2] asm qualifiers (PR55681) Segher Boessenkool
2018-12-03 22:20 ` Joseph Myers
2018-12-05 21:47 ` Jason Merrill
2018-12-05 23:02 ` Segher Boessenkool
2018-12-02 16:40 ` [PATCH 2/2] asm inline Segher Boessenkool
2018-12-02 17:23 ` Marc Glisse
2018-12-02 17:45 ` Segher Boessenkool
2018-12-02 18:38 ` Marc Glisse
2018-12-04 15:31 ` Richard Sandiford
2018-12-06 3:03 ` Segher Boessenkool [this message]
2018-12-06 18:11 ` [PATCH v2 0/2] asm qualifiers (PR55681) and " Segher Boessenkool
2018-12-06 18:15 ` Jakub Jelinek
2018-12-06 18:19 ` Joseph Myers
2018-12-06 18:54 ` Segher Boessenkool
-- strict thread matches above, loose matches on Subject: below --
2018-10-30 18:01 [PATCH 0/2] asm qualifiers (PR55681) and asm input Segher Boessenkool
2018-10-30 18:41 ` [PATCH 2/2] asm inline Segher Boessenkool
2018-10-30 18:58 ` Marek Polacek
2018-11-11 21:33 ` Martin Sebor
2018-11-11 22:01 ` Segher Boessenkool
2018-11-11 23:41 ` Martin Sebor
2018-11-12 0:19 ` Segher Boessenkool
2018-11-30 13:14 ` Richard Biener
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