Nim-lang GCC Auto vectorization (SIMD)

Object.nim

import random, raylib

randomize()

type
  Unit = object
    pos: Vector2
    hp: int

let size = rand(5..22)
var units = newSeq[Unit](size)

proc moveUnits(seq: var openArray[Unit], offset: Vector2) =
  for i in 0..<seq.len:
    seq[i].pos.x += offset.x
    seq[i].pos.y += offset.y

let randomOffset = Vector2(x: rand(-3.0..3.0), y: rand(-3.0..3.0))
moveUnits(units, randomOffset)

echo "Final positions:"
for u in units:
  echo u.pos
  
#@mOptmizable.nim.c:107:8: optimized: loop vectorized using 32 byte vectors

Optmizable.nim

import random, sequtils

randomize()

let size = rand(5..15)
var numbers = newSeq[int](size)

proc increment(seq: var openArray[int]) =
  for i in 0..<seq.len:
    seq[i] = seq[i] + 1

increment(numbers)

echo "Final: ", numbers

#@mOptmizable.nim.c:81:8: optimized: loop vectorized using 32 byte vectors

#nim c -r -d:danger --verbosity:3 --passC:"-fopt-info-vec-optimized -march=native"

Optmizable_mitems.nim

import random

randomize()

let size = rand(5..18)
var numbers = newSeq[int](size)

proc increment(seq: var openArray[int]) =
  for x in mitems(seq):
    x += 2

increment(numbers)

echo "Final: ", numbers

#@mOptmizable.nim.c:78:8: optimized: loop vectorized using 32 byte vectors

#nim c -r -d:danger --verbosity:3 --passC:"-fopt-info-vec-optimized -march=native"

RefObject.nim

import random, raylib

randomize()

type
  Unit = ref object
    pos: Vector2
    hp: int

let size = rand(5..22)
var units = newSeq[Unit](size)

for i in 0..<size:
  units[i] = Unit(pos: Vector2(x: 0.0, y: 0.0), hp: 100)

proc moveUnits(seq: var openArray[Unit], offset: Vector2) =
  for i in 0..<seq.len:
    seq[i].pos.x += offset.x
    seq[i].pos.y += offset.y

let randomOffset = Vector2(x: rand(-3.0..3.0), y: rand(-3.0..3.0))
moveUnits(units, randomOffset)

echo "Final positions:"
for u in units:
  echo u.pos
  
#@mOpt.nim.c:178:34: missed: not vectorized: no vectype for stmt: _5 = *_4;

toOpenArray.nim

import random

randomize()

let size = rand(5..19)
var numbers = newSeq[int](size)

for x in mitems(numbers.toOpenArray(0, numbers.high)):
  x = x + 1

echo "Final: ", numbers

#@mOptmizable.nim.c:149:8: missed: not vectorized: number of iterations cannot be computed.

Unoptimizable.nim

import random, sequtils

randomize()

let size = rand(5..15)
var numbers = newSeq[int](size)

for i in 0..<numbers.len:
  numbers[i] = numbers[i] + 1

echo "Final: ", numbers

#nim c -r -d:danger --verbosity:3 --passC:"-fopt-info-vec-optimized -march=native"