From 5f8570b933e524d3b0bc378d1e4cdba1498fbf3d Mon Sep 17 00:00:00 2001
From: Shaun Ren <sren@codeweavers.com>
Date: Fri, 4 Oct 2024 20:15:57 -0400
Subject: [PATCH] vkd3d-shader/hlsl: Track whether a variable is read in any
 entry function.

---
 libs/vkd3d-shader/hlsl.h         |  2 ++
 libs/vkd3d-shader/hlsl_codegen.c | 18 +++++++++++++++++-
 libs/vkd3d-shader/tpf.c          |  2 +-
 3 files changed, 20 insertions(+), 2 deletions(-)

diff --git a/libs/vkd3d-shader/hlsl.h b/libs/vkd3d-shader/hlsl.h
index 6a43ed9d..6bec38d0 100644
--- a/libs/vkd3d-shader/hlsl.h
+++ b/libs/vkd3d-shader/hlsl.h
@@ -488,6 +488,8 @@ struct hlsl_ir_var
      *   range). The IR instructions are numerated starting from 2, because 0 means unused, and 1
      *   means function entry. */
     unsigned int first_write, last_read;
+    /* Whether the variable is read in any entry function. */
+    bool is_read;
     /* Offset where the variable's value is stored within its buffer in numeric register components.
      * This in case the variable is uniform. */
     unsigned int buffer_offset;
diff --git a/libs/vkd3d-shader/hlsl_codegen.c b/libs/vkd3d-shader/hlsl_codegen.c
index 4bf34d56..653afdc1 100644
--- a/libs/vkd3d-shader/hlsl_codegen.c
+++ b/libs/vkd3d-shader/hlsl_codegen.c
@@ -4383,6 +4383,21 @@ static void compute_liveness(struct hlsl_ctx *ctx, struct hlsl_ir_function_decl
     compute_liveness_recurse(&entry_func->body, 0, 0);
 }
 
+static void mark_vars_usage(struct hlsl_ctx *ctx)
+{
+    struct hlsl_scope *scope;
+    struct hlsl_ir_var *var;
+
+    LIST_FOR_EACH_ENTRY(scope, &ctx->scopes, struct hlsl_scope, entry)
+    {
+        LIST_FOR_EACH_ENTRY(var, &scope->vars, struct hlsl_ir_var, scope_entry)
+        {
+            if (var->last_read)
+                var->is_read = true;
+        }
+    }
+}
+
 struct register_allocator
 {
     struct allocation
@@ -5286,7 +5301,7 @@ static void hlsl_calculate_buffer_offset(struct hlsl_ctx *ctx, struct hlsl_ir_va
 
     TRACE("Allocated buffer offset %u to %s.\n", var->buffer_offset, var->name);
     buffer->size = max(buffer->size, var->buffer_offset + var_reg_size);
-    if (var->last_read)
+    if (var->is_read)
         buffer->used_size = max(buffer->used_size, var->buffer_offset + var_reg_size);
 }
 
@@ -7726,6 +7741,7 @@ static void process_entry_function(struct hlsl_ctx *ctx, struct hlsl_ir_function
     while (hlsl_transform_ir(ctx, dce, body, NULL));
 
     compute_liveness(ctx, entry_func);
+    mark_vars_usage(ctx);
 
     transform_derefs(ctx, mark_indexable_vars, body);
 
diff --git a/libs/vkd3d-shader/tpf.c b/libs/vkd3d-shader/tpf.c
index ff86970d..d0ca6e8d 100644
--- a/libs/vkd3d-shader/tpf.c
+++ b/libs/vkd3d-shader/tpf.c
@@ -3864,7 +3864,7 @@ static void write_sm4_rdef(struct hlsl_ctx *ctx, struct dxbc_writer *dxbc)
             {
                 uint32_t flags = 0;
 
-                if (var->last_read)
+                if (var->is_read)
                     flags |= D3D_SVF_USED;
 
                 put_u32(&buffer, 0); /* name */