Compiler fails to convert loop into memcpy / vectorize it

[Waqar144]

Context

Consider the following simple code:

@require
test_fn2 :: proc(length: int) #no_bounds_check {
    arr1 := make([]int, length + 1)
    arr2 := make([]int, length + 1)

    for i := 0; i <= length; i += 1 {
        arr1[i] = arr2[i]
    }
}

The compiler fails to vectorize it or turn it into a memcpy. If the loop end condition is modified to be just <, it gets vectorized:

    for i := 0; i < length; i += 1 { // vectorizes

Link to compiler explorer: https://compiler-explorer.com/z/TM74EcfKh

---

• Operating System & Odin Version: Linux, dev-2024-12
• Please paste odin report output:

Odin:    dev-2024-12-nightly
OS:      Manjaro Linux, Linux 6.6.63-1-MANJARO
CPU:     AMD Ryzen 7 4700U with Radeon Graphics         
RAM:     15355 MiB
Backend: LLVM 18.1.6