Stack overflow when having loops containing if statements

[guipublic]

Problem

The PR AztecProtocol/aztec-packages#4571 is failing CI because it reaches a stack overflow during the ssa flatenning.
I managed to get a minimal repro with the following code:

fn main(x: u8, result: [u8; 32]) {
    let mut digest = [0;32];
    for i in 0..70 {
        let y = x+i;
    let a = [y ,x,32,0,y+1,y-1,2*y,5];
    digest = std::sha256::digest(a);
    }

    assert(digest == result);
}

Happy Case

The flattening pass is using recursion and should be changed into an iterative version

Project Impact

None

Impact Context

No response

Workaround

None

Workaround Description

No response

Additional Context

No response

Would you like to submit a PR for this Issue?

Yes

Support Needs

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