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From: Rich Felker <dalias@libc.org>
To: Adhemerval Zanella <adhemerval.zanella@linaro.org>
Cc: Nicholas Piggin <npiggin@gmail.com>,
	libc-alpha@sourceware.org, musl@lists.openwall.com,
	linuxppc-dev@lists.ozlabs.org, libc-dev@lists.llvm.org
Subject: Re: [musl] Powerpc Linux 'scv' system call ABI proposal take 2
Date: Thu, 16 Apr 2020 14:44:51 -0400	[thread overview]
Message-ID: <20200416184451.GB11469@brightrain.aerifal.cx> (raw)
In-Reply-To: <20200416183151.GA11469@brightrain.aerifal.cx>

On Thu, Apr 16, 2020 at 02:31:51PM -0400, Rich Felker wrote:
> > While on musl:
> > 
> > 0000000000000000 <kill>:
> >    0:	48 83 ec 08          	sub    $0x8,%rsp
> >    4:	48 63 ff             	movslq %edi,%rdi
> >    7:	48 63 f6             	movslq %esi,%rsi
> >    a:	b8 3e 00 00 00       	mov    $0x3e,%eax
> >    f:	0f 05                	syscall 
> >   11:	48 89 c7             	mov    %rax,%rdi
> >   14:	e8 00 00 00 00       	callq  19 <kill+0x19>
> >   19:	5a                   	pop    %rdx
> >   1a:	c3                   	retq   
> 
> Wow that's some extraordinarily bad codegen going on by gcc... The
> sign-extension is semantically needed and I don't see a good way
> around it (glibc's asm is kinda a hack taking advantage of kernel not
> looking at high bits, I think), but the gratuitous stack adjustment
> and refusal to generate a tail call isn't. I'll see if we can track
> down what's going on and get it fixed.

It seems to be https://gcc.gnu.org/bugzilla/show_bug.cgi?id=14441
which I've updated with a comment about the above.

Rich

  reply	other threads:[~2020-04-16 18:45 UTC|newest]

Thread overview: 62+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-04-15 21:45 Nicholas Piggin
2020-04-15 22:55 ` Rich Felker
2020-04-16  0:16   ` Nicholas Piggin
2020-04-16  0:48     ` Rich Felker
2020-04-16  2:24       ` Nicholas Piggin
2020-04-16  2:35         ` Rich Felker
2020-04-16  2:53           ` Nicholas Piggin
2020-04-16  3:03             ` Rich Felker
2020-04-16  3:41               ` Nicholas Piggin
2020-04-16 20:18             ` Florian Weimer
2020-04-16  9:58     ` Szabolcs Nagy
2020-04-20  0:27       ` Nicholas Piggin
2020-04-20  1:29         ` Rich Felker
2020-04-20  2:08           ` Nicholas Piggin
2020-04-20 21:17             ` Szabolcs Nagy
2020-04-21  9:57               ` Florian Weimer
2020-04-16 15:21     ` Jeffrey Walton
2020-04-16 15:40       ` Rich Felker
2020-04-16  4:48   ` Florian Weimer
2020-04-16 15:35     ` Rich Felker
2020-04-16 16:42       ` Florian Weimer
2020-04-16 16:52         ` Rich Felker
2020-04-16 18:12           ` Florian Weimer
2020-04-16 23:02             ` Segher Boessenkool
2020-04-17  0:34               ` Rich Felker
2020-04-17  1:48                 ` Segher Boessenkool
2020-04-17  8:34                   ` Florian Weimer
2020-04-16 14:16   ` Adhemerval Zanella
2020-04-16 15:37     ` Rich Felker
2020-04-16 17:50       ` Adhemerval Zanella
2020-04-16 17:59         ` Rich Felker
2020-04-16 18:18           ` Adhemerval Zanella
2020-04-16 18:31             ` Rich Felker
2020-04-16 18:44               ` Rich Felker [this message]
2020-04-16 18:52               ` Adhemerval Zanella
2020-04-20  0:46                 ` Nicholas Piggin
2020-04-20  1:10               ` Nicholas Piggin
2020-04-20  1:34                 ` Rich Felker
2020-04-20  2:32                   ` Nicholas Piggin
2020-04-20  4:09                     ` Rich Felker
2020-04-20  4:31                       ` Nicholas Piggin
2020-04-20 17:27                         ` Rich Felker
2020-04-22  6:18                           ` Nicholas Piggin
2020-04-22  6:29                             ` Nicholas Piggin
2020-04-23  2:36                             ` Rich Felker
2020-04-23 12:13                               ` Adhemerval Zanella
2020-04-23 16:18                                 ` Rich Felker
2020-04-23 16:35                                   ` Adhemerval Zanella
2020-04-23 16:43                                     ` Rich Felker
2020-04-23 17:15                                       ` Adhemerval Zanella
2020-04-23 17:42                                         ` Rich Felker
2020-04-25  3:40                                           ` Nicholas Piggin
2020-04-25  4:52                                             ` Rich Felker
2020-04-25  3:30                               ` Nicholas Piggin
2020-04-21 12:28                 ` David Laight
2020-04-21 14:39                   ` Rich Felker
2020-04-21 15:00                     ` Adhemerval Zanella
2020-04-21 15:31                       ` David Laight
2020-04-22  6:54                       ` [musl] " Nicholas Piggin
2020-04-22  7:15                         ` Florian Weimer
2020-04-22  7:31                           ` Nicholas Piggin
2020-04-22  8:11                             ` Florian Weimer

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