From: Richard Biener <richard.guenther@gmail.com>
To: Peter Bergner <bergner@linux.ibm.com>
Cc: Qing Zhao <qing.zhao@oracle.com>, GCC Patches <gcc-patches@gcc.gnu.org>
Subject: Re: [PATCH] middle-end: Skip initialization of opaque type register variables [PR103127]
Date: Wed, 1 Dec 2021 10:01:58 +0100 [thread overview]
Message-ID: <CAFiYyc0JNVtVikyu+3zt_AY2K-Wykdrwx_JHEYpE=iSKrA2fBA@mail.gmail.com> (raw)
In-Reply-To: <ef98506d-a7f2-bcfd-c797-53b2511ee558@linux.ibm.com>
On Tue, Nov 30, 2021 at 11:35 PM Peter Bergner <bergner@linux.ibm.com> wrote:
>
> On 11/30/21 2:44 PM, Qing Zhao via Gcc-patches wrote:
> > Sorry for the confusing…
> > My major question is:
> >
> > for a variable of type __vector_pair, could it be in a register?
>
> Yes. To be pedantic, it will live in a vector register pair.
>
>
> > If it could be in a register, can we initialize this register with some constant value?
>
> For a __vector_pair, no, not as it is setup now. We also do not have a
> use case where we would want to initialize a __vector_pair to a constant.
> Our normal (only?) use case with a __vector_pair is to load it up with
> some actual data from memory that represents a (partial) row of a matrix.
>
> For __vector_quad, it too lives in a register (accumulator register) and
> represents a small matrix. We have the __builtin_mma_xxsetaccz (&acc)
> builtin to initialize it to a zero constant.
Given all this I suggest to exempt OPAQUE_TYPE from is_var_need_auto_init
instead of fixing up things at expansion time.
Richard.
> Peter
>
next prev parent reply other threads:[~2021-12-01 9:02 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-11-29 21:56 Peter Bergner
2021-11-29 22:56 ` Qing Zhao
2021-11-30 8:37 ` Richard Biener
2021-11-30 15:14 ` Peter Bergner
2021-11-30 17:51 ` Qing Zhao
2021-11-30 18:08 ` Peter Bergner
2021-11-30 19:50 ` Qing Zhao
2021-11-30 20:07 ` Peter Bergner
2021-11-30 20:44 ` Qing Zhao
2021-11-30 22:35 ` Peter Bergner
2021-12-01 9:01 ` Richard Biener [this message]
2021-12-01 15:06 ` Qing Zhao
2021-12-01 16:08 ` Peter Bergner
2021-12-01 17:42 ` Peter Bergner
2021-12-01 19:07 ` Richard Biener
2021-12-01 19:29 ` Peter Bergner
2021-11-30 17:59 ` Qing Zhao
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