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From: Eric Botcazou <ebotcazou@adacore.com>
To: Richard Henderson <rth@redhat.com>
Cc: gcc-patches@gcc.gnu.org, Bernd Schmidt <bschmidt@redhat.com>,
	Abe <abe_skolnik@yahoo.com>, Sebastian Pop <sebpop@gmail.com>,
	Kyrill Tkachov <kyrylo.tkachov@arm.com>
Subject: Re: using scratchpads to enhance RTL-level if-conversion: revised patch
Date: Wed, 14 Oct 2015 08:29:00 -0000	[thread overview]
Message-ID: <1975913.Fx1EfbHjAv@polaris> (raw)
In-Reply-To: <561DAA48.60604@redhat.com>

> If you're using one of the switches that checks for stack overflow at the
> start of the function, you certainly don't want to do any such stores.

There is a protection area for -fstack-check (STACK_CHECK_PROTECT bytes) so 
you can do stores just below the stack pointer as far as it's concerned.

There is indeed the issue of the mere writing below the stack pointer.  Our 
experience with various OSes and architectures shows that this almost always 
works.  The only problematic case is x86{-64}/Linux historically, where you 
cannot write below the page pointed to by the stack pointer (that's why there 
is a specific implementation of -fstack-check for x86{-64}/Linux).

-- 
Eric Botcazou

  parent reply	other threads:[~2015-10-14  8:29 UTC|newest]

Thread overview: 19+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-10-07 23:29 Abe
2015-10-08 13:09 ` Sebastian Pop
2015-10-08 13:20   ` Sebastian Pop
2015-10-08 13:26     ` Bernd Schmidt
2015-10-08 13:23 ` Bernd Schmidt
2015-10-13 19:34   ` Abe
2015-10-13 20:16     ` Bernd Schmidt
2015-10-14 17:43       ` Jeff Law
2015-10-14 19:15         ` Bernd Schmidt
2015-10-15  8:52           ` Richard Biener
2015-10-20  5:52           ` Jeff Law
2015-10-20  9:37             ` Richard Biener
2015-10-14  1:05   ` Richard Henderson
2015-10-14  1:11     ` Richard Henderson
2015-10-14  8:29     ` Eric Botcazou [this message]
2015-10-14 17:46       ` Jeff Law
2015-10-13 20:05 Abe
     [not found] <024301d11106$2379b5f0$6a6d21d0$@samsung.com>
2015-10-27 23:02 ` Abe
2015-10-30 14:09   ` Bernd Schmidt

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