Compiler optimizing while True loop away

[lsh]

Bug description

The following code will result in no output with mojo file.mojo

Steps to reproduce

Run mojo file.mojo where the file contains:

fn main():
    var i = 0
    while True:
        for j in range(i):
            print_no_newline(j, " ")
        print()
        if i > 10:
            break
        i += 1

System information

Ubuntu 22.04 in a devcontainer on an Intel MacBook pro.

[abduld]

Also

fn main():
    var i = 0
    while i < 10:
        for j in range(i):
            print_no_newline(j, " ")
        print()
        i += 1

prints a few new lines but does not print the value of j

This

fn main():
    for i in range(10):
        for j in range(i):
            print_no_newline(j, " ")
        print()

works fine though

[weiweichen]

Reopen to wait for another PR to merge.