From: Qing Zhao <qing.zhao@oracle.com>
To: Peter Bergner <bergner@linux.ibm.com>,
Richard Biener <richard.guenther@gmail.com>
Cc: "GCC Patches" <gcc-patches@gcc.gnu.org>, "Martin Liška" <mliska@suse.cz>
Subject: Re: [PATCH] middle-end: Skip initialization of opaque type register variables [PR103127]
Date: Mon, 29 Nov 2021 22:56:12 +0000 [thread overview]
Message-ID: <B059F36C-5B20-4F4D-A7BD-1AAEF3D8E6B8@oracle.com> (raw)
In-Reply-To: <ccb5f603-5c1f-0e59-31d9-07251f81e0aa@linux.ibm.com>
Peter,
Thanks a lot for the patch.
Richard, how do you think of the patch?
(The major concern for me is:
With the current patch proposed by Peter, we will generate the call to .DEFERRED_INIT for a variable with OPAQUE_TYPE during gimplification phase,
However, if this variable is in register, then the call to .DEFERRED_INIT will NOT be expanded during RTL expansion phase. This unexpanded call to .DEFERRED_INIT might cause some potential IR issue later?
If the above is a real issue, should we skip initialization for all OPAQUE_TYPE variables even when they are in memory and can be initialized with memset?
then we should update “is_var_need_auto_init” in gimplify.c instead. However, the issue with this approach is, we might miss the opportunity to initialize an OPAQUE_TYPE variable if it will be in memory?
).
Thanks.
Qing
> On Nov 29, 2021, at 3:56 PM, Peter Bergner <bergner@linux.ibm.com> wrote:
>
> Sorry for dropping the ball on testing the patch from the bugzilla!
>
> The following patch fixes the ICE reported in the bugzilla on the pre-existing
> gcc testsuite test case, bootstraps and shows no testsuite regressions
> on powerpc64le-linux. Ok for trunk?
>
> Peter
>
>
> For -ftrivial-auto-var-init=*, skip initializing the register variable if it
> is an opaque type, because CONST0_RTX(mode) is not defined for opaque modes.
>
> gcc/
> PR middle-end/103127
> * internal-fn.c (expand_DEFERRED_INIT): Skip if VAR_TYPE is opaque.
>
> diff --git a/gcc/internal-fn.c b/gcc/internal-fn.c
> index 0cba95411a6..7cc0e9d5293 100644
> --- a/gcc/internal-fn.c
> +++ b/gcc/internal-fn.c
> @@ -3070,6 +3070,10 @@ expand_DEFERRED_INIT (internal_fn, gcall *stmt)
> }
> else
> {
> + /* Skip variables of opaque types that are in a register. */
> + if (OPAQUE_TYPE_P (var_type))
> + return;
> +
> /* If this variable is in a register use expand_assignment.
> For boolean scalars force zero-init. */
> tree init;
next prev parent reply other threads:[~2021-11-29 22:56 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 [this message]
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
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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