Mesa (main): nouveau/nir: Allow up to 6 nested joins

[GitLab Mirror]

Module: Mesa
Branch: main
Commit: 9da14a21193425dfb02d620e3da7eed954119b68
URL:    http://cgit.freedesktop.org/mesa/mesa/commit/?id=9da14a21193425dfb02d620e3da7eed954119b68

Author: M Henning <drawoc at darkrefraction.com>
Date:   Tue Feb  8 01:00:02 2022 -0500

nouveau/nir: Allow up to 6 nested joins

This matches what the tgsi path does and doesn't regress any tests. (For
comparison, unlimited join nesting does regress tests in deqp and piglit)

Fixes graphical artifacts from stack overflows in
https://www.shadertoy.com/view/Xds3zN
with nir on kepler

Reviewed-by: Emma Anholt <emma at anholt.net>
Acked-by: Karol Herbst <kherbst at redhat.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/15597>

---

 src/gallium/drivers/nouveau/codegen/nv50_ir_from_nir.cpp | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/src/gallium/drivers/nouveau/codegen/nv50_ir_from_nir.cpp b/src/gallium/drivers/nouveau/codegen/nv50_ir_from_nir.cpp
index f9703fe7cde..192f2f59c1b 100644
--- a/src/gallium/drivers/nouveau/codegen/nv50_ir_from_nir.cpp
+++ b/src/gallium/drivers/nouveau/codegen/nv50_ir_from_nir.cpp
@@ -1485,9 +1485,9 @@ Converter::visit(nir_if *nif)
       insertJoins = insertJoins && bb->getExit()->op == OP_BRA;
    }
 
-   /* only insert joins for the most outer if */
-   if (--curIfDepth)
+   if (curIfDepth > 6) {
       insertJoins = false;
+   }
 
    /* we made sure that all threads would converge at the same block */
    if (insertJoins) {
@@ -1498,6 +1498,8 @@ Converter::visit(nir_if *nif)
       mkFlow(OP_JOIN, NULL, CC_ALWAYS, NULL)->fixed = 1;
    }
 
+   curIfDepth--;
+
    return true;
 }