WGSL Bug

Code

@group(0)
@binding(0)
var<storage, read_write> flow: array<u32, 2>;

@compute
@workgroup_size(1)
fn main() {
    var LOOP_COUNTER: u32 = 0u;
    loop {
        (flow)[0u] += 1u;
        if (LOOP_COUNTER >= 1u) {
            (flow)[1u] += 1u;
            break;
        }
        LOOP_COUNTER += 1u;
    }
}

Expected output is [2, 1] after executing break statement in second iteration of loop.

Results

/	<>	<>	<>	<>	<>	<>	<>
	Vendor	GPU	Dawn Vulkan Linux	wGPU Vulkan Linux	Dawn Vulkan Windows	wGPU Vulkan Windows	Dawn DX12 Windows	wGPU DX12 Windows
	Nvidia	RTX 2060 Max-Q	Timeout	ND[fn:1]	Zeros[fn:2]	Zeros[fn:2]	Correct	Correct
	Nvidia	RTX 2060 Super	Timeout	ND[fn:1]	Zeros[fn:2]		Correct	Correct
	Nvidia	GTX 1050 Ti	Timeout	Correct	Zeros[fn:2]	Correct	Correct	Correct
	Nvidia	Quadro 4000	Correct	Correct
	AMD	Ryzen 9 4900HS (iGPU)	Correct	Correct
	Intel	i7-9700K (iGPU)	Correct	Inconsistent[fn:3]
	Intel	i5-7400 (iGPU)	Correct	Correct

[fn:1] Non Deterministic results where the first element is large and the second element is zero; produces correct result if either of the flow increments are removed.

[fn:2] Output is [0, 0], presumed to be as a result of a timeout.

[fn:3] Sometimes produces correct output, other times produces [0, 0] without timing out.