[PATCH 1/2] vkd3d-shader/spirv: Handle UINT32_MAX result for FIRSTBIT_HI and FIRSTBIT_SHI.

[Conor McCarthy]

From: Conor McCarthy

---
 libs/vkd3d-shader/spirv.c | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/libs/vkd3d-shader/spirv.c b/libs/vkd3d-shader/spirv.c
index e8068f3a3..b5bcd1a4c 100644
--- a/libs/vkd3d-shader/spirv.c
+++ b/libs/vkd3d-shader/spirv.c
@@ -6892,11 +6892,11 @@ static enum GLSLstd450 spirv_compiler_map_ext_glsl_instruction(
 static void spirv_compiler_emit_ext_glsl_instruction(struct spirv_compiler *compiler,
         const struct vkd3d_shader_instruction *instruction)
 {
+    uint32_t instr_set_id, type_id, val_id, rev_val_id, uint_max_id, condition_id;
     struct vkd3d_spirv_builder *builder = &compiler->spirv_builder;
     const struct vkd3d_shader_dst_param *dst = instruction->dst;
     const struct vkd3d_shader_src_param *src = instruction->src;
     uint32_t src_id[SPIRV_MAX_SRC_COUNT];
-    uint32_t instr_set_id, type_id, val_id;
     unsigned int i, component_count;
     enum GLSLstd450 glsl_inst;

@@ -6925,8 +6925,12 @@ static void spirv_compiler_emit_ext_glsl_instruction(struct spirv_compiler *comp
     {
         /* In D3D bits are numbered from the most significant bit. */
         component_count = vsir_write_mask_component_count(dst->write_mask);
-        val_id = vkd3d_spirv_build_op_isub(builder, type_id,
+        uint_max_id = spirv_compiler_get_constant_uint_vector(compiler, UINT32_MAX, component_count);
+        condition_id = vkd3d_spirv_build_op_tr2(builder, &builder->function_stream, SpvOpIEqual,
+                vkd3d_spirv_get_type_id(builder, VKD3D_SHADER_COMPONENT_BOOL, component_count), val_id, uint_max_id);
+        rev_val_id = vkd3d_spirv_build_op_isub(builder, type_id,
                 spirv_compiler_get_constant_uint_vector(compiler, 31, component_count), val_id);
+        val_id = vkd3d_spirv_build_op_select(builder, type_id, condition_id, val_id, rev_val_id);
     }

spirv_compiler_emit_store_dst(compiler, dst, val_id);