From 56d7dad19cf286ef43aa066e31a71e91954481dc Mon Sep 17 00:00:00 2001
From: Mike Blumenkrantz <michael.blumenkrantz@gmail.com>
Date: Mon, 18 Mar 2024 09:14:07 -0400
Subject: [PATCH] nir/lower_clamp_color_outputs: fix use with lowered io
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if io is lowered, variables cannot be used

cc: mesa-stable

Acked-by: Marek Olšák <marek.olsak@amd.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/28463>
---
 .../nir/nir_lower_clamp_color_outputs.c       | 27 +++++++------------
 1 file changed, 10 insertions(+), 17 deletions(-)

diff --git a/src/compiler/nir/nir_lower_clamp_color_outputs.c b/src/compiler/nir/nir_lower_clamp_color_outputs.c
index c13e90705d7..37e40f89a28 100644
--- a/src/compiler/nir/nir_lower_clamp_color_outputs.c
+++ b/src/compiler/nir/nir_lower_clamp_color_outputs.c
@@ -25,13 +25,13 @@
 #include "nir_builder.h"
 
 static bool
-is_color_output(nir_shader *shader, nir_variable *out)
+is_color_output(nir_shader *shader, int location)
 {
    switch (shader->info.stage) {
    case MESA_SHADER_VERTEX:
    case MESA_SHADER_GEOMETRY:
    case MESA_SHADER_TESS_EVAL:
-      switch (out->data.location) {
+      switch (location) {
       case VARYING_SLOT_COL0:
       case VARYING_SLOT_COL1:
       case VARYING_SLOT_BFC0:
@@ -42,8 +42,8 @@ is_color_output(nir_shader *shader, nir_variable *out)
       }
       break;
    case MESA_SHADER_FRAGMENT:
-      return (out->data.location == FRAG_RESULT_COLOR ||
-              out->data.location >= FRAG_RESULT_DATA0);
+      return (location == FRAG_RESULT_COLOR ||
+              location >= FRAG_RESULT_DATA0);
    default:
       return false;
    }
@@ -54,30 +54,23 @@ lower_intrinsic(nir_builder *b, nir_intrinsic_instr *intr, nir_shader *shader)
 {
    nir_variable *out = NULL;
    nir_def *s;
+   int loc = -1;
 
    switch (intr->intrinsic) {
    case nir_intrinsic_store_deref:
       out = nir_intrinsic_get_var(intr, 0);
+      if (out->data.mode != nir_var_shader_out)
+         return false;
+      loc = out->data.location;
       break;
    case nir_intrinsic_store_output:
-      /* already had i/o lowered.. lookup the matching output var: */
-      nir_foreach_shader_out_variable(var, shader) {
-         int drvloc = var->data.driver_location;
-         if (nir_intrinsic_base(intr) == drvloc) {
-            out = var;
-            break;
-         }
-      }
-      assume(out);
+      loc = nir_intrinsic_io_semantics(intr).location;
       break;
    default:
       return false;
    }
 
-   if (out->data.mode != nir_var_shader_out)
-      return false;
-
-   if (is_color_output(shader, out)) {
+   if (is_color_output(shader, loc)) {
       b->cursor = nir_before_instr(&intr->instr);
       int src = intr->intrinsic == nir_intrinsic_store_deref ? 1 : 0;
       s = intr->src[src].ssa;