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Re: [PATCH 6/6] Compile sched_getaffinity.c with -fno-builtin-memset

On Fri, Aug 14, 2015 at 9:11 AM, Joseph Myers <> wrote:
> On Fri, 14 Aug 2015, H.J. Lu wrote:
>> > We're declaring (essentially, though a load of macros):
>> >
>> > extern __typeof (memset) memset __asm__ ("__GI_memset") __attribute__ ((visibility ("hidden")));
>> >
>> > GCC is using the __asm__ information to compile calls to __builtin_memset
>> > to use the assembler name __GI_memset - that is, in that regard our
>> > declaration is being taken as applying to the libcall.  If it's not also
>> > using the visibility information to know that those are calls within the
>> > library and don't need to set up %ebx, that's a clear inconsistency; all
>> > pieces of information from an explicit declaration of a built-in function
>> > should be treated the same unless there is a clear reason not to do so.
>> >
>> Should I open a GCC bug?
> If you wish (and have verified that %ebx is being unnecessarily set up).
> It's a missed optimization rather than an actual bug.

I withdrew my patch and opened:


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