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Re: [PATCH][PR66010] Don't take address of ap unless necessary
- From: Tom de Vries <Tom_deVries at mentor dot com>
- To: Michael Matz <matz at suse dot de>
- Cc: Richard Biener <rguenther at suse dot de>, GCC Patches <gcc-patches at gcc dot gnu dot org>
- Date: Tue, 12 May 2015 12:38:09 +0200
- Subject: Re: [PATCH][PR66010] Don't take address of ap unless necessary
- Authentication-results: sourceware.org; auth=none
- References: <554D0BE4 dot 8090305 at mentor dot com> <alpine dot LSU dot 2 dot 20 dot 1505121209560 dot 4883 at wotan dot suse dot de>
On 12-05-15 12:12, Michael Matz wrote:
Hi,
On Fri, 8 May 2015, Tom de Vries wrote:
III.
Using the patch, before inlining we can see the address operator has been
removed in va_arg:
...
f2_1 (struct * apD.1832)
{
intD.6 _4;
# .MEM_3 = VDEF <.MEM_1(D)>
# USE = anything
# CLB = anything
_4 = VA_ARG (ap_2(D), 0B, 0);
# VUSE <.MEM_3>
return _4;
}
Have you visually inspected that the address operator stays on
architectures where va_list is e.g. a char pointer
x86_64 -m32:
...
f2 (int i)
{
charD.2 * ap.0D.1811;
intD.1 D.1812;
intD.1 resD.1808;
charD.2 * apD.1809;
try
{
# USE = anything
# CLB = anything
__builtin_va_startD.1021 (&apD.1809, 0);
ap.0D.1811 = apD.1809;
# USE = anything
# CLB = anything
resD.1808 = f2_1D.1803 (ap.0D.1811);
# USE = anything
# CLB = anything
__builtin_va_endD.1020 (&apD.1809);
D.1812 = resD.1808;
return D.1812;
}
finally
{
apD.1809 = {CLOBBER};
}
}
f2_1 (char * ap)
{
intD.1 D.1815;
# USE = anything
# CLB = anything
D.1815 = VA_ARG (&apD.1802, 0B, 1);
return D.1815;
}
...
Thanks,
- Tom
(i.e. on those where
VA_ARG has the side-effect of modifying ap)?