From: Jeff Law <jeffreyalaw@gmail.com>
To: Philipp Tomsich <philipp.tomsich@vrull.eu>, gcc-patches@gcc.gnu.org
Cc: Thiago Jung Bauermann <thiago.bauermann@linaro.org>,
Tamar Christina <Tamar.Christina@arm.com>,
Jakub Jelinek <jakub@gcc.gnu.org>,
Richard Biener <rguenth@gcc.gnu.org>,
Sergei Trofimovich <slyfox@gcc.gnu.org>,
Andrew Pinski <pinskia@gcc.gnu.org>,
Tobian Burnus <burnus@gcc.gnu.org>, Jeff Law <law@gcc.gnu.org>,
Kito Cheng <kito.cheng@gmail.com>,
Manolis Tsamis <manolis.tsamis@vrull.eu>
Subject: Re: [PATCH] cprop_hardreg: fix ORIGINAL_REGNO/REG_ATTRS/REG_POINTER handling
Date: Sun, 25 Jun 2023 07:09:47 -0600 [thread overview]
Message-ID: <a7fa1942-80f3-4156-a64f-ffab744174c6@gmail.com> (raw)
In-Reply-To: <20230622111154.2837175-1-philipp.tomsich@vrull.eu>
On 6/22/23 05:11, Philipp Tomsich wrote:
> From: Manolis Tsamis <manolis.tsamis@vrull.eu>
>
> Fixes: 6a2e8dcbbd4bab3
>
> Propagation for the stack pointer in regcprop was enabled in
> 6a2e8dcbbd4bab3, but set ORIGINAL_REGNO/REG_ATTRS/REG_POINTER for
> stack_pointer_rtx which caused regression (e.g., PR 110313, PR 110308).
>
> This fix adds special handling for stack_pointer_rtx in the places
> where maybe_mode_change is called. This also adds an check in
> maybe_mode_change to return the stack pointer only when the requested
> mode matches the mode of stack_pointer_rtx.
>
> PR 110308
Should be
PR debug/110308
>
> gcc/ChangeLog:
>
> * regcprop.cc (maybe_mode_change): Check stack_pointer_rtx mode.
> (find_oldest_value_reg): Special handling of stack_pointer_rtx.
> (copyprop_hardreg_forward_1): Ditto.
>
> gcc/testsuite/ChangeLog:
>
> * g++.dg/torture/pr110308.C: New test.
I don't doubt the need for the special handling of the stack pointer,
but it's not obvious why it's needed. So my request is that both humks
which specialize handling of ORIGINAL_REGNO, REG_ATTRS & REG_POINTER
have a comment indicating why we must not adjust those values when
NEW_RTX is STACK_POINTER_RTX.
OK with that change.
Jeff
next prev parent reply other threads:[~2023-06-25 13:09 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-06-22 11:11 Philipp Tomsich
2023-06-23 4:08 ` Andrew Pinski
2023-06-25 13:09 ` Jeff Law [this message]
2023-06-28 14:10 ` Philipp Tomsich
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