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From: "hpa at zytor dot com" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug other/56314] Please allow per-function specification of register conventions
Date: Thu, 14 Feb 2013 02:24:00 -0000	[thread overview]
Message-ID: <bug-56314-4-SXOTAP960A@http.gcc.gnu.org/bugzilla/> (raw)
In-Reply-To: <bug-56314-4@http.gcc.gnu.org/bugzilla/>


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=56314

--- Comment #2 from H. Peter Anvin <hpa at zytor dot com> 2013-02-14 02:23:53 UTC ---
Consider the following syntax:

__attribute__((saved(...),used(...),fixed(...)))

... as the equivalent to -fcall-saved-*, -fcall-used-*, and -ffixed-*
respectively.

In Linux/x86-64 we could then decorate the function __sw_hweight64() as:

unsigned long __attribute__((saved(rdi,rsi,rdx,rcx,r8,r9,r10,r11)))
__sw_hweight64(__u64 v);

One major use for this for us is to be able to reduce the call site impact of
certain small functions by reducing the used set of those functions.

Please let me know if you need more examples.


  parent reply	other threads:[~2013-02-14  2:24 UTC|newest]

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2013-02-14  1:56 [Bug other/56314] New: " hpa at zytor dot com
2013-02-14  2:04 ` [Bug other/56314] " pinskia at gcc dot gnu.org
2013-02-14  2:24 ` hpa at zytor dot com [this message]
2013-02-14 10:29 ` [Bug middle-end/56314] " rguenth at gcc dot gnu.org
2013-02-15  6:52 ` benh at kernel dot crashing.org
2013-02-15  6:56 ` pinskia at gcc dot gnu.org
2022-10-03 16:20 ` hpa at zytor dot com

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