ntt: lower indirect tesslevels in ntt

Tessellation shader which are using indirect
addressing for tesslevels e.g
  gl_TessLevelOuter[gl_InvocationID] = tessLevelOuter;
are crashing because gl_TessLevelOuter is now a
compact array variable and nir expects a constant
array index into the compact array variable.

This patch handles such cases.

This fixes MR 21940
Fixes: 84006587d7e5 ("glsl: Delete the lower_tess_level pass.")
Tested with glretrace

Reviewed-by: Charmaine Lee <charmainel@vmware.com>
Reviewed-by: Emma Anholt <emma@anholt.net>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/25773>
(cherry picked from commit 8cfb46e27dfb12acdb1a00f7687a43899d770cca)

diff --git a/.pick_status.json b/.pick_status.json
index e50dc6ffda0029972b1a4f506f6404bbc8c2c228..b26e0f5ef426c68e0a52b5ef417f580c581704fc 100644 (file)
--- a/.pick_status.json
+++ b/.pick_status.json
@@ -1764,7 +1764,7 @@
         "description": "ntt: lower indirect tesslevels in ntt",
         "nominated": true,
         "nomination_type": 1,
-        "resolution": 0,
+        "resolution": 1,
         "main_sha": null,
         "because_sha": "84006587d7e5b87526a9b83135393251afeef777",
         "notes": null

diff --git a/src/gallium/auxiliary/nir/nir_to_tgsi.c b/src/gallium/auxiliary/nir/nir_to_tgsi.c
index 521a643d0fb4122012810676967d4d85a5a1cd58..4cf7fbc20c481cb9839706ebf5b95051e85a289e 100644 (file)
--- a/src/gallium/auxiliary/nir/nir_to_tgsi.c
+++ b/src/gallium/auxiliary/nir/nir_to_tgsi.c
@@ -3898,6 +3898,15 @@ const void *nir_to_tgsi_options(struct nir_shader *s,
       NIR_PASS_V(s, nir_remove_dead_variables, nir_var_shader_in, NULL);
    }
 
+   /* Lower tesslevel indirect derefs for tessellation shader.
+    * tesslevels are now a compact array variable and nir expects a constant
+    * array index into the compact array variable.
+    */
+   if (s->info.stage == MESA_SHADER_TESS_CTRL ||
+       s->info.stage == MESA_SHADER_TESS_EVAL) {
+      NIR_PASS_V(s, nir_lower_indirect_derefs, 0 , UINT32_MAX);
+   }
+
    NIR_PASS_V(s, nir_lower_io, nir_var_shader_in | nir_var_shader_out,
               type_size, (nir_lower_io_options)0);