r600: Disable SB if we use the ariable length DOT

sb doesn't know about this instruction, so don't try to run the
optimizer.

Signed-off-by: Gert Wollny <gert.wollny@collabora.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/23647>

src/gallium/drivers/r600/r600_shader.c

@@ -240,6 +240,7 @@ int r600_pipe_shader_create(struct pipe_context *ctx,
 	use_sb &= !shader->shader.uses_atomics;
 	use_sb &= !shader->shader.uses_images;
 	use_sb &= !shader->shader.uses_helper_invocation;
+        use_sb &= !shader->shader.disable_sb;
 
 	/* SB can't handle READ_SCRATCH properly */
 	use_sb &= !(shader->shader.needs_scratch_space && rscreen->b.gfx_level < R700);

src/gallium/drivers/r600/r600_shader.h

@@ -125,6 +125,7 @@ struct r600_shader {
 	uint8_t                 atomic_base;
 	uint8_t			rat_base;
 	uint8_t                 image_size_const_offset;
+        boolean			disable_sb;
 };
 
 union r600_shader_key {

src/gallium/drivers/r600/sfn/sfn_instr_alu.cpp

@@ -2643,6 +2643,8 @@ emit_dot(const nir_alu_instr& alu, int n, Shader& shader)
       ir->set_alu_flag(alu_dst_clamp);
 
    shader.emit_instruction(ir);
+   shader.set_flag(Shader::sh_disble_sb);
+
    return true;
 }
 

src/gallium/drivers/r600/sfn/sfn_shader.cpp

@@ -1567,6 +1567,7 @@ Shader::get_shader_info(r600_shader *sh_info)
    sh_info->needs_scratch_space = m_flags.test(sh_needs_scratch_space);
    sh_info->uses_images = m_flags.test(sh_uses_images);
    sh_info->uses_atomics = m_flags.test(sh_uses_atomics);
+   sh_info->disable_sb = m_flags.test(sh_disble_sb);
    sh_info->has_txq_cube_array_z_comp = m_flags.test(sh_txs_cube_array_comp);
    sh_info->indirect_files = m_indirect_files;
    do_get_shader_info(sh_info);

src/gallium/drivers/r600/sfn/sfn_shader.h

@@ -227,6 +227,7 @@ public:
       sh_indirect_atomic,
       sh_mem_barrier,
       sh_legacy_math_rules,
+      sh_disble_sb,
       sh_flags_count
    };