From: Jeff Law <law@redhat.com>
To: Wilco Dijkstra <Wilco.Dijkstra@arm.com>,
GCC Patches <gcc-patches@gcc.gnu.org>
Cc: nd <nd@arm.com>
Subject: Re: [PATCH] Fix PR46932: Block auto increment on frame pointer
Date: Tue, 25 Jul 2017 20:42:00 -0000 [thread overview]
Message-ID: <27a1b18b-a698-f50d-f026-1dc956e3c673@redhat.com> (raw)
In-Reply-To: <AM5PR0802MB2610C93E52AAFEFD3A1DA5B283A70@AM5PR0802MB2610.eurprd08.prod.outlook.com>
On 07/20/2017 08:49 AM, Wilco Dijkstra wrote:
> Block auto increment on frame pointer references. This is never
> beneficial since the SFP expands into SP+C or FP+C during register
> allocation. The generated code for the testcase is now as expected:
>
> str x30, [sp, -32]!
> strb w0, [sp, 31]
> add x0, sp, 31
> bl foo3
> ldr x30, [sp], 32
> ret
>
> On SPEC2017 codesize improves uniformly across the board.
>
> ChangeLog:
> 2017-07-20 Wilco Dijkstra <wdijkstr@arm.com>
>
> PR middle-end/46932
> * auto-inc-dec.c (parse_add_or_inc): Block autoinc on sfp.
>
> gcc/testsuite/
>
> * gcc.dg/pr46932.c: New testcase.
My only concern here would be cases where we don't end up eliminating FP
to SP. But I'd think it's unlikely that we'd have enough auto-inc
opportunities on the frame pointer for it to matter much anyway.
OK for the trunk.
jeff
next prev parent reply other threads:[~2017-07-25 20:42 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-07-20 14:49 Wilco Dijkstra
2017-07-25 20:42 ` Jeff Law [this message]
2017-07-25 21:25 ` Wilco Dijkstra
2017-07-25 22:29 ` Jeff Law
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