[Bug tree-optimization/68537] Vectorizer possibly miscompiles dynamic linker with -O3

[fw at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=68537

--- Comment #3 from Florian Weimer <fw at gcc dot gnu.org> ---
(In reply to Markus Trippelsdorf from comment #0)
> rbp            0x7fffffffa148   0x7fffffffa148

(In reply to Markus Trippelsdorf from comment #2)
> 0000000000001470 <_dl_lookup_symbol_x>:
>     1470:       55                      push   %rbp
>     1471:       48 89 e5                mov    %rsp,%rbp

>     14f4:       0f 29 45 80             movaps %xmm0,-0x80(%rbp)

If I'm reading this correctly, %rsp was a multiple of 16 when the function is
entered, but this is not correct, it has to be congruent 8 modulo 16.

This looks like a GHC or GHCi bug (which may already have been fixed).