Incorrect if/else result when a loop in a branch reassigns the condition variable #2156

When a loop inside the if branch reassigns the variable used as the condition, the if/else gives the wrong result.

import warp as wp


@wp.kernel
def repro(flags: wp.array[int], n: int, out: wp.array[int]):
    i = wp.tid()
    flag = int(flags[i])
    if flag:
        for _ in range(n):
            flag = 0
        value = 11
    else:
        value = 22
    out[i] = value


flags = wp.array([1, 0], dtype=int)
out = wp.empty(2, dtype=int)
wp.launch(repro, dim=2, inputs=[flags, 1], outputs=[out])
print(out.numpy().tolist())

Expected: [11, 22]

Actual: [22, 22]

The first flag starts as 1, so the first result should be 11. Clearing flag inside the loop should not change which result is selected.

The reverse case fails too. Moving the loop into the else branch and setting flag = 1 there gives [11, 11]. A while loop behaves the same way. The output is correct when n is 0, or when the loop uses a constant count such as range(1).

Reproduced with Warp 1.12.0, 1.17.0, and 1.18.0 on CPU and CUDA, in both release and debug modes, using Linux and Python 3.12.