From: Jeff Law <jlaw@ventanamicro.com>
To: Manolis Tsamis <manolis.tsamis@vrull.eu>,
Palmer Dabbelt <palmer@dabbelt.com>
Cc: gcc-patches@gcc.gnu.org, Vineet Gupta <vineetg@rivosinc.com>,
Kito Cheng <kito.cheng@gmail.com>,
philipp.tomsich@vrull.eu
Subject: Re: [PATCH] Enable shrink wrapping for the RISC-V target.
Date: Wed, 2 Nov 2022 09:06:36 -0600 [thread overview]
Message-ID: <4afcf3c0-690c-1168-b5e2-b6542b85d8e9@ventanamicro.com> (raw)
In-Reply-To: <CAM3yNXpanKFLFz3JgVkmhxzvN4OVhPZ37dsHb6guuJLVM8HCjQ@mail.gmail.com>
On 11/2/22 07:54, Manolis Tsamis wrote:
>
> I've revisited this testcase and I think it's not possible to make it
> work with the current implementation.
> It's not possible to trigger shrink wrapping in this case since the
> wrapping of registers is guarded by
> if (SMALL_OPERAND (offset)) { bitmap_set_bit (components, regno); }
> Hence if a long stack is generated we get no shrink wrapping.
>
> I also tried to remove that restriction but it looks like it can't
> work because we can't create
> pseudo-registers during shrink wrapping and shrink wrapping can't work either.
>
> I believe this means that shrink wrapping cannot interfere with a long
> stack frame
> so there is nothing to test against in this case?
It'd be marginally better to have such a test case to ensure we don't
shrink wrap it -- that would ensure that someone doesn't accidentally
introduce shrink wrapping with large offsets. Just a bit of future
proofing.
Jeff
next prev parent reply other threads:[~2022-11-02 15:06 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-09-06 10:39 mtsamis
2022-10-02 20:32 ` Palmer Dabbelt
2022-10-18 15:18 ` Manolis Tsamis
2022-10-18 15:57 ` Jeff Law
2022-10-18 17:35 ` Palmer Dabbelt
2022-10-19 17:15 ` Jeff Law
2022-10-20 7:42 ` Manolis Tsamis
2022-11-02 14:12 ` Manolis Tsamis
2022-11-02 15:02 ` Jeff Law
2022-10-20 7:35 ` Manolis Tsamis
2022-11-02 13:54 ` Manolis Tsamis
2022-11-02 15:06 ` Jeff Law [this message]
2022-11-03 0:26 ` Palmer Dabbelt
2022-11-03 22:23 ` Jeff Law
2022-11-07 22:07 ` Palmer Dabbelt
2022-11-13 1:32 ` Jeff Law
2022-11-16 10:26 ` Manolis Tsamis
2022-11-17 2:09 ` Jeff Law
2022-11-17 10:54 ` Manolis Tsamis
2022-11-17 11:59 ` Philipp Tomsich
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