From: Andreas Schwab <schwab@linux-m68k.org>
To: David Edelsohn via Gcc-patches <gcc-patches@gcc.gnu.org>
Cc: Segher Boessenkool <segher@kernel.crashing.org>,
David Edelsohn <dje.gcc@gmail.com>
Subject: Re: [PATCH] Inline IBM long double __gcc_qsub
Date: Thu, 26 Aug 2021 09:40:41 +0200 [thread overview]
Message-ID: <87pmu0wt52.fsf@igel.home> (raw)
In-Reply-To: <CAGWvny=Xe8TXx1Z6QUABj85-UAjGrRDfUYJBdqQUR2Txp9gg3g@mail.gmail.com> (David Edelsohn via Gcc-patches's message of "Wed, 25 Aug 2021 20:23:32 -0400")
On Aug 25 2021, David Edelsohn via Gcc-patches wrote:
> rs6000: inline ldouble __gcc_qsub
>
> While performing some tests of IEEE 128 float for PPC64LE, Michael
> Meissner noticed that __gcc_qsub is substantially slower than
> __gcc_qadd. __gcc_qsub valls __gcc_add with the second operand
> negated. Because the functions normally are invoked through
> libgcc shared object, the extra PLT overhead has a large impact
> on the overall time of the function. Instead of trying to be
> fancy with function decorations to prevent interposition, this
> patch inlines the definition of __gcc_qadd into __gcc_qsub with
> the negation propagated through the function.
>
> libgcc/ChangeLog:
>
> * config/rs6000/ibm-ldouble.c (__gcc_qsub): Inline negated
> __gcc_qadd.
How about defining a static function that is used by both?
Andreas.
--
Andreas Schwab, schwab@linux-m68k.org
GPG Key fingerprint = 7578 EB47 D4E5 4D69 2510 2552 DF73 E780 A9DA AEC1
"And now for something completely different."
next prev parent reply other threads:[~2021-08-26 7:40 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-08-26 0:23 David Edelsohn
2021-08-26 7:35 ` Andreas Schwab
2021-08-26 7:40 ` Andreas Schwab [this message]
2021-08-26 18:57 ` [PATCH v2] " David Edelsohn
2021-08-26 22:51 ` Segher Boessenkool
2021-08-26 23:07 ` David Edelsohn
2021-08-26 12:15 ` [PATCH] " Segher Boessenkool
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