From: Segher Boessenkool <segher@kernel.crashing.org>
To: Jakub Jelinek <jakub@redhat.com>
Cc: gcc-patches@gcc.gnu.org, richard.sandiford@arm.com
Subject: Re: [PATCH 0/3] RFC: Let debug stmts influence codegen at -Og
Date: Mon, 24 Jun 2019 14:36:00 -0000 [thread overview]
Message-ID: <20190624143639.GG7313@gate.crashing.org> (raw)
In-Reply-To: <20190624142834.GL815@tucnak>
On Mon, Jun 24, 2019 at 04:28:34PM +0200, Jakub Jelinek wrote:
> On Sun, Jun 23, 2019 at 02:51:06PM +0100, Richard Sandiford wrote:
> > What do you think? Is it worth pursuing this further?
>
> Wouldn't it be more useful to just force all automatic variables to be
> used at the end of their corresponding scope? That is IMHO the main issue
> with -Og debugging, VTA is a best effort, if we can express a variable with
> some expression, nice, but if there is no expression nor memory nor register
> that holds the value, we are out of luck. Could be some magic stmt like
> gimple_clobber or ifn or something similar, which would make sure that at
> least until expansion to RTL we force those vars to be live in either a
> register or memory.
> I'm afraid having different modes, one in which debug stmts can't and one
> where they can affect code generation might be a maintainance nightmare.
This is pretty much exactly what USE in RTL is? Maybe use a similar name
in Gimple?
Segher
next prev parent reply other threads:[~2019-06-24 14:36 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-06-23 13:51 Richard Sandiford
2019-06-23 13:52 ` [PATCH 1/3] RFC: Add a mode in which debug stmts participate in codegen Richard Sandiford
2019-06-23 13:53 ` [PATCH 0/3] RFC: Keep debug values live for -Og Richard Sandiford
2019-06-23 13:53 ` [PATCH 3/3] RFC: Add -O1g Richard Sandiford
2019-06-24 12:24 ` [PATCH 0/3] RFC: Let debug stmts influence codegen at -Og Richard Biener
2019-06-24 12:50 ` Richard Sandiford
2019-06-24 14:14 ` Segher Boessenkool
2019-06-24 14:22 ` Richard Sandiford
2019-06-24 14:28 ` Jakub Jelinek
2019-06-24 14:36 ` Segher Boessenkool [this message]
2019-06-24 16:10 ` Richard Sandiford
2019-06-26 8:38 ` [PATCH 0/3] RFC: Let debug stmts influence codegen@-Og Jonathan Wakely
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