intel/compiler: Reverse inclusion dependency between brw_vec4_live_variables.h and brw_vec4.h

brw_vec4.h (in particular vec4_visitor) is logically a user of the
live variables analysis pass, not the other way around.
brw_vec4_live_variables.h requires the definition of some VEC4 IR data
structures to compile, but those can be obtained directly from
brw_ir_vec4.h without including brw_vec4.h.

Reviewed-by: Matt Turner <mattst88@gmail.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/4012>

src/intel/compiler/brw_vec4.cpp

@@ -26,7 +26,6 @@
 #include "brw_cfg.h"
 #include "brw_nir.h"
 #include "brw_vec4_builder.h"
-#include "brw_vec4_live_variables.h"
 #include "brw_vec4_vs.h"
 #include "brw_dead_control_flow.h"
 #include "dev/gen_debug.h"

src/intel/compiler/brw_vec4.h

@@ -29,6 +29,7 @@
 #ifdef __cplusplus
 #include "brw_ir_vec4.h"
 #include "brw_vec4_builder.h"
+#include "brw_vec4_live_variables.h"
 #endif
 
 #include "compiler/glsl/ir.h"
@@ -52,9 +53,6 @@ brw_vec4_generate_assembly(const struct brw_compiler *compiler,
 } /* extern "C" */
 
 namespace brw {
-
-class vec4_live_variables;
-
 /**
  * The vertex shader front-end.
  *

src/intel/compiler/brw_vec4_live_variables.cpp

@@ -25,7 +25,7 @@
  *
  */
 
-#include "brw_cfg.h"
+#include "brw_vec4.h"
 #include "brw_vec4_live_variables.h"
 
 using namespace brw;

src/intel/compiler/brw_vec4_live_variables.h

@@ -28,8 +28,8 @@
 #ifndef BRW_VEC4_LIVE_VARIABLES_H
 #define BRW_VEC4_LIVE_VARIABLES_H
 
+#include "brw_ir_vec4.h"
 #include "util/bitset.h"
-#include "brw_vec4.h"
 
 namespace brw {