Mesa (master): nir/dead_cf: Don't crash on unreachable after-loop blocks

[Jason Ekstrand]

Module: Mesa
Branch: master
Commit: 9a4d76e534920a54c28092311ab6da90c6d7b8d3
URL:    http://cgit.freedesktop.org/mesa/mesa/commit/?id=9a4d76e534920a54c28092311ab6da90c6d7b8d3

Author: Jason Ekstrand <jason.ekstrand at intel.com>
Date:   Wed Aug 31 16:35:21 2016 -0700

nir/dead_cf: Don't crash on unreachable after-loop blocks

Signed-off-by: Jason Ekstrand <jason at jlekstrand.net>
Reviewed-by: Connor Abbott <cwabbott0 at gmail.com>

---

 src/compiler/nir/nir_opt_dead_cf.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/src/compiler/nir/nir_opt_dead_cf.c b/src/compiler/nir/nir_opt_dead_cf.c
index 3551124..1490e68 100644
--- a/src/compiler/nir/nir_opt_dead_cf.c
+++ b/src/compiler/nir/nir_opt_dead_cf.c
@@ -205,7 +205,8 @@ loop_is_dead(nir_loop *loop)
    nir_metadata_require(impl, nir_metadata_live_ssa_defs |
                               nir_metadata_dominance);
 
-   for (nir_block *cur = after->imm_dom; cur != before; cur = cur->imm_dom) {
+   for (nir_block *cur = after->imm_dom; cur && cur != before;
+        cur = cur->imm_dom) {
       nir_foreach_instr(instr, cur) {
          if (!nir_foreach_ssa_def(instr, def_not_live_out, after))
             return false;