Compiler fails with internal error when compare two wrapped into struct SIMD vectors
No crash with ordinal types like (int) or B{int i;}
Note: simd vectors doesn't provide opEquals, you should use v1.array == v2.array

Code:

import core.simd;

struct S
{
    int4 vec;
}
void main()
{
    S s, b;
    assert(s == b);
}

dub test --compiler=gdc

gdc-catch-bug ~master: building configuration "application"...
source/app.d: In function 'D main':
source/app.d:7:6: internal compiler error: in prepare_cmp_insn, at optabs.c:4234
 void main()
      ^
gdc --version
gdc (GCC) 5.3.0

OS: ArchLinux, x86_64