From: Segher Boessenkool <segher@kernel.crashing.org>
To: Andrew Stubbs <ams@codesourcery.com>
Cc: gcc mailing list <gcc@gcc.gnu.org>
Subject: Re: Register allocation cost question
Date: Tue, 10 Oct 2023 14:09:30 -0500 [thread overview]
Message-ID: <20231010190930.GV19790@gate.crashing.org> (raw)
In-Reply-To: <9c350ebd-fd67-4975-abee-68787f97c383@codesourcery.com>
Hi Andrew,
On Tue, Oct 10, 2023 at 04:11:18PM +0100, Andrew Stubbs wrote:
> I'm also seeing wrong-code bugs when I allow more than 32 new registers,
> but that might be an unrelated problem. Or the allocation is broken? I'm
> still analyzing this.
It could be connected. both things should not happen.
> If it matters, ... the new registers can't be used for general purposes,
What does this mean? I think you mean they *can* be used for anything,
you just don't want to (maybe it is slow)? If you make it allocatable
registers, they *will* be allocated for anythin the compilers deems a
good idea.
> so I'm trying to set them up as a temporary spill destination. This
> means they're typically not busy. It feels like it shouldn't be this
> hard... :(
So what did you do, put them later in the allocation order? Make their
register_move_cost higher than for normal registers (but still below
memory_move_cost)? Or what? TARGEt_SPILL_CLASS maybe?
Segher
next prev parent reply other threads:[~2023-10-10 19:10 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-10-10 15:11 Andrew Stubbs
2023-10-10 19:09 ` Segher Boessenkool [this message]
2023-10-11 8:57 ` Andrew Stubbs
2023-10-11 14:49 ` Andrew Stubbs
2023-10-11 6:54 ` Chung-Lin Tang
2023-10-11 8:58 ` Andrew Stubbs
2023-10-11 10:56 ` Richard Earnshaw (lists)
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