Compile-time comparison of optionals (== / !=)

[foobles]

This will allow code like this to function at compile time, partially implementing #1332:

const x: ?i32 = get_some_optional();
const y: ?i32 = get_another_optional();
if (x == y) {
    do_a_thing();
}

if (x != y) {
    do_another_thing();
}

Which currently only works for optional pointers.
I will work on making this runtime soon.

One thing I am not completely sure about: when calling ir_analyze_optional_value_payload_value(), I am not sure if it should be given op1/op2->base, or bin_op_instruction->base.base for the source_instr parameter.

[mikdusan]

One thing I am not completely sure about: when calling ir_analyze_optional_value_payload_value(), I am not sure if it should be given op1/op2->base, or bin_op_instruction->base.base for the source_instr parameter.

foo.zig

export fn entry() void {
    var oa: ?u32 = 999;
    var a = oa orelse 0;
    if (oa) |uw| {}
}

ir_analyze_optional_value_payload_value seems to be a pretty rare call, so trapping for ir_analyze_unwrap_optional_payload instead the above source code hits 3 times:

source_instr	line:col	base_ptr	line:col
999	2:20	var	2:5
orelse	3:16	var	2:5
if	4:15	var	2:5

so I'd say bin_op_instruction is good for source_instr

[foobles]

@mikdusan Alright, I fixed it. I also added error checking after the unwraps, which after looking in the other code that uses the function, seems necessary.

[foobles]

This did not have intended behavior. I will be back soon with a correct version also with runtime support.