[For-Loop] Properties of Condition

[ebehner]

Proposal

Currently, we transform a while-loop into a for-loop independent of the condition. However, for-loops where the condition is a comparison like a == 10 or a != 10 are rather rare (except for pointers).

In the following example (test1_c in test_goto.zip), we have the condition var_0 == 15 in a for-loop with is rather unusual.

int test1_c() {
    int var_0;
    var_0 = 10;
    do {
        for (var_0; var_0 == 15; var_0 += 2) {
            printf("We go to the loop head.", var_0);
        }
        printf("value of a: %d\n", var_0);
        var_0++;
    }
    while (var_0 <= 19);
    return 0;
}

Here, a while loop would look more natural, i.e.,

int test1_c() {
    int var_0;
    var_0 = 10;
    do {
        while (var_0 == 15) {
            printf("We go to the loop head.", var_0);
            var_0 += 2;
        }
        printf("value of a: %d\n", var_0);
        var_0++;
    }
    while (var_0 <= 19);
    return 0;
}

Approach

Add a configuration option for the condition of for-loops.

• [ ] which comparisons are allowed
• [ ] how long/complex can the condition be