stage2: orelse at comptime is broken

[g-w1]

This should work, but it does not:

export fn _start() noreturn {
    const b: ?comptime_int = 5;
    const v: comptime_int = b orelse 4;
    unreachable;
}

test.zig:3:31: error: expected pointer, found 'comptime_int'

Here is the untyped zir:

fn_type _start { // unanalyzed
  %0 = const(TypedValue{ .ty = type, .val = type})
  %1 = const(TypedValue{ .ty = type, .val = noreturn})
  %2 = as(%0, %1)
  %3 = fntype([], %2, cc=Unspecified)
} // fn_type _start

fn_body _start { // unanalyzed
  %0 = dbg_stmt()
  %1 = const(TypedValue{ .ty = type, .val = type})
  %2 = const(TypedValue{ .ty = type, .val = type})
  %3 = const(TypedValue{ .ty = type, .val = comptime_int})
  %4 = as(%2, %3)
  %5 = optional_type(%4)
  %6 = as(%1, %5)
  %7 = const(TypedValue{ .ty = comptime_int, .val = 5})
  %8 = as(%6, %7) ; I think this is the problem. An optional comptime int is not a pointer, but if it is null, it never gets referenced.
  %9 = dbg_stmt()
  %10 = const(TypedValue{ .ty = type, .val = type})
  %11 = const(TypedValue{ .ty = type, .val = comptime_int})
  %12 = as(%10, %11)
  %13 = ref(%8)
  %14 = deref(%13)
  %15 = isnull(%14)
  %16 = block({
    %17 = condbr(%15, {
      %18 = const(TypedValue{ .ty = comptime_int, .val = 4})
      %19 = as(%12, %18)
      %20 = break("label_16", %19)
    }, {
      %21 = unwrap_optional_unsafe(%13)
      %22 = break("label_16", %21)
    })
  })
  %23 = deref(%16)
  %24 = as(%12, %23)
  %25 = dbg_stmt()
  %26 = unreachable()
} // fn_body _start

I think the problem is the %23 = deref(%16) line, which is coming from rlWrapPtr at the end of orelseCatchExpr
Adding this does not fix it:

32c32,33
<       %22 = break("label_16", %21)
---
>       %22 = ref(%21)
>       %23 = break("label_16", %22)

Note, this does work:

export fn _start() noreturn {
    const b: ?comptime_int = null;
    const v: comptime_int = b orelse 4;
    unreachable;
}

This seems like a very easy fix, I just cannot think of a fix.

Edit:
Im pretty sure it is because of the resultLoc mechanism:

  %16 = block({
    %17 = condbr(%15, {
      %18 = const(TypedValue{ .ty = comptime_int, .val = 4})
      %19 = as(%12, %18)
      %20 = break("label_16", %19)
    }, {
      %21 = unwrap_optional_unsafe(%13)
      %22 = break("label_16", %21)
    })
  })

Here, %19 = as(%12, %18) is because of the .ty resultloc. We also need to use the resultloc in the else branch

Edit Edit:
it is actually because of the rlWrapPtr at the end of orelseCatchExpr. Changing it to rlWrap fixes it for the case where b != null, but breaks for b == null. It shows this:

fn_type _start { // unanalyzed
  %0 = const(TypedValue{ .ty = type, .val = type})
  %1 = const(TypedValue{ .ty = type, .val = noreturn})
  %2 = as(%0, %1)
  %3 = fntype([], %2, cc=Unspecified)
} // fn_type _start

fn_body _start { // unanalyzed
  %0 = dbg_stmt()
  %1 = const(TypedValue{ .ty = type, .val = type})
  %2 = const(TypedValue{ .ty = type, .val = type})
  %3 = const(TypedValue{ .ty = type, .val = comptime_int})
  %4 = as(%2, %3)
  %5 = optional_type(%4)
  %6 = as(%1, %5)
  %7 = const(TypedValue{ .ty = @Type(.Null), .val = null})
  %8 = as(%6, %7)
  %9 = dbg_stmt()
  %10 = const(TypedValue{ .ty = type, .val = type})
  %11 = const(TypedValue{ .ty = type, .val = comptime_int})
  %12 = as(%10, %11)
  %13 = ref(%8)
  %14 = deref(%13)
  %15 = isnull(%14)
  %16 = block({
    %17 = condbr(%15, {
      %18 = const(TypedValue{ .ty = comptime_int, .val = 4})
      %19 = as(%12, %18)
      %20 = break("label_16", %19)
    }, {
      %21 = unwrap_optional_unsafe(%13)
      %22 = break("label_16", %21)
    })
  })
  %23 = as(%12, %16)
  %24 = dbg_stmt()
  %25 = unreachable()
} // fn_body _start

test.zig:3:31: error: expected comptime_int, found *comptime_int

The reason I am submitting this is because it is a blocker for writing tests for #7628 since this also affects catch, which #7628 allows to be run at comptime.

[g-w1]

@Vexu pinging you because you seem to have written the code.