[Bug dynamic-link/19289] gcc-6 emits movaps instructions for dl-lookup.o with -O3

["markus at trippelsdorf dot de" <sourceware-bugzilla at sourceware dot org>]

https://sourceware.org/bugzilla/show_bug.cgi?id=19289

--- Comment #1 from Markus Trippelsdorf <markus at trippelsdorf dot de> ---
Forgot to mention: This causes the dynamic linker to segfault:

markus@x4 glibc-build % gdb --args
/var/tmp/glibc-build/elf/ld-linux-x86-64.so.2 /home/markus/bin/xmonad
Reading symbols from /var/tmp/glibc-build/elf/ld-linux-x86-64.so.2...done.
(gdb) run
Starting program: /var/tmp/glibc-build/elf/ld-linux-x86-64.so.2
/home/markus/bin/xmonad
[Thread debugging using libthread_db enabled]
Using host libthread_db library "/lib/libthread_db.so.1".

Program received signal SIGSEGV, Segmentation fault.
_dl_lookup_symbol_x (undef_name=0x7ffff75cb3c5 "__gmpn_invert_limb",
undef_map=0x7ffff76494d0, ref=ref@entry=0x7fffffffa170,
symbol_scope=0x7ffff7649828, version=0x0, 
    type_class=type_class@entry=1, flags=1, skip_map=0x0) at dl-lookup.c:809
809       struct sym_val current_value = { NULL, NULL };
(gdb) bt
#0  _dl_lookup_symbol_x (undef_name=0x7ffff75cb3c5 "__gmpn_invert_limb",
undef_map=0x7ffff76494d0, ref=ref@entry=0x7fffffffa170,
symbol_scope=0x7ffff7649828, version=0x0, 
    type_class=type_class@entry=1, flags=1, skip_map=0x0) at dl-lookup.c:809
#1  0x0000555555564413 in _dl_fixup (l=<optimized out>, reloc_arg=<optimized
out>) at ../elf/dl-runtime.c:111
#2  0x000055555556ce1f in _dl_runtime_resolve_sse () at
../sysdeps/x86_64/dl-trampoline.h:112
#3  0x00007ffff762093a in __gmpn_divrem_1 () from /usr/lib/libgmp.so.10
#4  0xee6b280000000000 in ?? ()
#5  0x00007ffff6b0b138 in ?? ()
#6  0x00007ffff6b057d0 in ?? ()
#7  0x00000000ffffffe2 in ?? ()
#8  0x00007ffff6b057b8 in ?? ()
#9  0x00007ffff6b051b0 in ?? ()
#10 0x00007ffff6b0b1b0 in ?? ()
#11 0x00000000006b47d8 in ?? ()
#12 0x00000000006142a9 in ?? ()
#13 0x0000000000000000 in ?? ()
(gdb) disass
Dump of assembler code for function _dl_lookup_symbol_x:
...
   0x000055555555e915 <+117>:   jne    0x55555555e900 <_dl_lookup_symbol_x+96>
   0x000055555555e917 <+119>:   mov    %eax,%eax
   0x000055555555e919 <+121>:   mov    %rax,-0xb0(%rbp)
   0x000055555555e920 <+128>:   pxor   %xmm0,%xmm0
   0x000055555555e924 <+132>:   mov    $0xffffffff,%eax
   0x000055555555e929 <+137>:   incq   0x21d048(%rip)        # 0x55555577b978
<_rtld_local+2424>
   0x000055555555e930 <+144>:   test   %r12,%r12
   0x000055555555e933 <+147>:   mov    %rax,-0xa0(%rbp)
=> 0x000055555555e93a <+154>:   movaps %xmm0,-0x90(%rbp)
   0x000055555555e941 <+161>:   je     0x55555555e950 <_dl_lookup_symbol_x+176>

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