From: Segher Boessenkool <segher@kernel.crashing.org>
To: Eric Botcazou <ebotcazou@adacore.com>
Cc: gcc-patches@gcc.gnu.org
Subject: Re: [rs6000] Do not generate sibling call to nested function
Date: Tue, 18 Sep 2018 15:26:00 -0000 [thread overview]
Message-ID: <20180918145610.GS23155@gate.crashing.org> (raw)
In-Reply-To: <2045800.G86V45WoCa@polaris>
Hi!
On Mon, Sep 17, 2018 at 11:11:53AM +0200, Eric Botcazou wrote:
> more precisely, to a nested function that requires a static chain. The reason
> is that the sibling call epilogue may clobber the static chain register r11.
>
> Tested on PowerPC/Linux, OK for the mainline?
>
>
> 2018-09-17 Eric Botcazou <ebotcazou@adacore.com>
>
> * config/rs6000/rs6000.c (rs6000_function_ok_for_sibcall): Return false
> if the call takes a static chain.
> --- config/rs6000/rs6000.c (revision 264342)
> +++ config/rs6000/rs6000.c (working copy)
> @@ -24332,6 +24332,10 @@ rs6000_function_ok_for_sibcall (tree dec
> {
> tree fntype;
>
> + /* The sibcall epilogue may clobber the static chain register. */
> + if (CALL_EXPR_STATIC_CHAIN (exp))
> + return false;
> +
> if (decl)
> fntype = TREE_TYPE (decl);
> else
We could probably make sibcalls work with static chain, but that is most
likely not worth it. Could you change the comment to say something like
that?
Approved for trunk and backports. Thanks!
Segher
next prev parent reply other threads:[~2018-09-18 14:56 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-09-17 9:14 Eric Botcazou
2018-09-18 15:26 ` Segher Boessenkool [this message]
2018-09-24 13:20 ` Kyrill Tkachov
2018-09-25 10:10 ` Eric Botcazou
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