Module: Mesa
Branch: staging/23.0
Commit: b96362381bcfb2e7e3c8eded353b6ac1d72bb105
URL:    
http://cgit.freedesktop.org/mesa/mesa/commit/?id=b96362381bcfb2e7e3c8eded353b6ac1d72bb105

Author: antonino <[email protected]>
Date:   Mon Feb 20 19:26:20 2023 +0100

nir: avoid generating conflicting output variables

Because not all vertex outputs can have corresponding fragment inputs
(eg. edgeflags) some logic is needed to correctly generate variables in
a passthough gs.

Before this change some output variables ened up with the same location.

Fixes: d0342e28b32 ("nir: Add helper to create passthrough GS shader")

Acked-by: Mike Blumenkrantz <[email protected]>
Reviewed-by: Erik Faye-Lund <[email protected]>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/21238>
(cherry picked from commit edecb66b01849effdf859f3cfaeebb9af5e1c1da)

---

 .pick_status.json                     |  2 +-
 src/compiler/nir/nir_passthrough_gs.c | 22 +++++++++++++++++-----
 2 files changed, 18 insertions(+), 6 deletions(-)

diff --git a/.pick_status.json b/.pick_status.json
index ecdc0883d11..fc5b7e2e637 100644
--- a/.pick_status.json
+++ b/.pick_status.json
@@ -2731,7 +2731,7 @@
         "description": "nir: avoid generating conflicting output variables",
         "nominated": true,
         "nomination_type": 1,
-        "resolution": 0,
+        "resolution": 1,
         "main_sha": null,
         "because_sha": "d0342e28b32d7aa4b25cf045ac9933348ec053a9"
     },
diff --git a/src/compiler/nir/nir_passthrough_gs.c 
b/src/compiler/nir/nir_passthrough_gs.c
index 4ba4f2c8380..82ff849911a 100644
--- a/src/compiler/nir/nir_passthrough_gs.c
+++ b/src/compiler/nir/nir_passthrough_gs.c
@@ -49,7 +49,7 @@ nir_create_passthrough_gs(const nir_shader_compiler_options 
*options,
 
    nir_variable *in_vars[VARYING_SLOT_MAX];
    nir_variable *out_vars[VARYING_SLOT_MAX];
-   unsigned num_vars = 0;
+   unsigned num_inputs = 0, num_outputs = 0;
 
    /* Create input/output variables. */
    nir_foreach_shader_out_variable(var, prev_stage) {
@@ -72,6 +72,15 @@ nir_create_passthrough_gs(const nir_shader_compiler_options 
*options,
       in->data.interpolation = var->data.interpolation;
       in->data.compact = var->data.compact;
 
+      in_vars[num_inputs++] = in;
+
+      nir->num_inputs++;
+      if (in->data.location == VARYING_SLOT_EDGE)
+         continue;
+
+      if (var->data.location != VARYING_SLOT_POS)
+         nir->num_outputs++;
+
       if (var->name)
          snprintf(name, sizeof(name), "out_%s", var->name);
       else
@@ -85,8 +94,7 @@ nir_create_passthrough_gs(const nir_shader_compiler_options 
*options,
       out->data.interpolation = var->data.interpolation;
       out->data.compact = var->data.compact;
 
-      in_vars[num_vars] = in;
-      out_vars[num_vars++] = out;
+      out_vars[num_outputs++] = out;
    }
 
    unsigned int start_vert = 0;
@@ -109,11 +117,15 @@ nir_create_passthrough_gs(const 
nir_shader_compiler_options *options,
 
    for (unsigned i = start_vert; i < end_vert; i += vert_step) {
       /* Copy inputs to outputs. */
-      for (unsigned j = 0; j < num_vars; ++j) {
+      for (unsigned j = 0, oj = 0; j < num_inputs; ++j) {
+         if (in_vars[j]->data.location == VARYING_SLOT_EDGE) {
+            continue;
+         }
          /* no need to use copy_var to save a lower pass */
          nir_ssa_def *value = nir_load_array_var_imm(&b, in_vars[j], i);
-         nir_store_var(&b, out_vars[j], value,
+         nir_store_var(&b, out_vars[oj], value,
                        (1u << value->num_components) - 1);
+         ++oj;
       }
       nir_emit_vertex(&b, 0);
    }

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