Bug 106174

Yeah, I noticed this too.

https://patchwork.freedesktop.org/patch/218205/

should fix this.

On Sun, Apr 22, 2018 at 05:28:45PM +0000, bugzilla-daemon@freedesktop.org wrote:
> https://bugs.freedesktop.org/show_bug.cgi?id=106174
> 
> --- Comment #1 from Bas Nieuwenhuizen <bas@basnieuwenhuizen.nl> ---
> Yeah, I noticed this too.
> 
> https://patchwork.freedesktop.org/patch/218205/
> 
> should fix this.

Since I'm not into nir, I just reverted the patch.

Your patch seems to do what the commit intended to do in the first place, though.

Fixed by:

author	Bas Nieuwenhuizen <bas@basnieuwenhuizen.nl>
commit	0e945fdf23bac5a62c15edfcbfd9d6ac4eee592f

nir: Do not use progress for unreachable code in return lowering.

We seem to use progress for two cases:
1) When we lowered some returns.
2) When we remove unreachable code.

If just case 2 happens we assert as state->return_flag has not
been allocated yet, but we are still trying to do insert all
predicates based on it.

This splits the concerns. We only use progress internally for case 1
and then keep track of 2 in a separate variable to indicate progress
in the return value of the pass.

This is slightly better than transforming the assert into
if (!state->return_flag) return, as the solution in this patch avoids
inserting predicates even if some other part of the might need them.

Fixes: 6e22ad6edc "nir: return early when lowering a return at the end of a function"
CC: 18.1 <mesa-stable@lists.freedesktop.org>
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=106174
Reviewed-by: Timothy Arceri <tarceri@itsqueeze.com>