[Bug middle-end/79649] Memset pattern in named address space crashes compiler or generates wrong code

[ubizjak at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=79649

--- Comment #12 from Uroš Bizjak <ubizjak at gmail dot com> ---
The added testcase also ICEs with -O3 -mx32:

~/gcc-build/gcc/cc1 -O3 -mx32 -quiet pr79649.c
pr79649.c: In function ‘f1’:
pr79649.c:11:1: internal compiler error: in get_use_type, at
tree-ssa-loop-ivopts.c:3831
 f1 (unsigned char __seg_gs *s, size_t n)
 ^~
0xff99a1 get_use_type
        ../../git/gcc/gcc/tree-ssa-loop-ivopts.c:3830
0xfff0c8 get_computation_at
        ../../git/gcc/gcc/tree-ssa-loop-ivopts.c:3847
0x1009aba get_computation_cost_at
        ../../git/gcc/gcc/tree-ssa-loop-ivopts.c:5061
0x1009c0f get_computation_cost
        ../../git/gcc/gcc/tree-ssa-loop-ivopts.c:5089
0x100a251 determine_group_iv_cost_address
        ../../git/gcc/gcc/tree-ssa-loop-ivopts.c:5133