From: Wilco Dijkstra <Wilco.Dijkstra@arm.com>
To: Richard Sandiford <Richard.Sandiford@arm.com>
Cc: GCC Patches <gcc-patches@gcc.gnu.org>,
Kyrylo Tkachov <Kyrylo.Tkachov@arm.com>
Subject: Re: [PATCH v2] AArch64: Improve GOT addressing
Date: Wed, 26 May 2021 12:24:05 +0000 [thread overview]
Message-ID: <VE1PR08MB5599AFD06D84E76B395E490483249@VE1PR08MB5599.eurprd08.prod.outlook.com> (raw)
In-Reply-To: <mptim353lp5.fsf@arm.com>
Hi Richard,
> Are we actually planning to do any linker relaxations here, or is this
> purely theoretical? If doing relaxations is a realistic possiblity then
> I agree that would be a good/legitimate reason to use a single define_insn
> for both instructions. In that case though, there should be a comment
> above the define_insn explaining that linker relaxation is the reason
> for keeping the instructions together.
Yes, enabling linker relaxations is a key goal of this patch - it's a chicken
and egg problem since compilers split the instructions and schedule them
apart for no good reason, making such relaxations impossible. It turns out
that splitting early is very bad for code quality, so we can achieve smaller
and faster code as well.
I'll merge in the .md changes of the previous version so we don't need
scheduling fusion.
Cheers,
Wilco
prev parent reply other threads:[~2021-05-26 12:24 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-05-24 12:12 Wilco Dijkstra
2021-05-26 9:09 ` Richard Sandiford
2021-05-26 12:24 ` Wilco Dijkstra [this message]
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