```
$ cat gep-vector.ll
define i32* @bitcast_vec_to_array_gep(<7 x i32>* %x, i64 %y, i64 %z) {
  %arr_ptr = bitcast <7 x i32>* %x to [7 x i32]*
  %gep = getelementptr [7 x i32], [7 x i32]* %arr_ptr, i64 %y, i64 %z
  ret i32* %gep
}
$ opt -instcombine gep-vector.ll -S -o -
define i32* @bitcast_vec_to_array_gep(<7 x i32>* %x, i64 %y, i64 %z) {
  %gep = getelementptr <7 x i32>, <7 x i32>* %x, i64 %y, i64 %z
  ret i32* %gep
}
```

This is incorrect because DataLayout::getTypeAllocSize(< 7 x i32 >) and getTypeAllocSize([ 7 x i32 ]) may differ.

This can be double-checked by emitting assembly code before/after optimization.
https://godbolt.org/z/xB-p5u
Before optimization, rax = rdi + 28 * rsi + 4 * rdx
After instcombine, rax = rdi + 32 * rsi + 4 * rdx.