intel/compiler: Add swsb_stall debug option

When enabled, on gfx12 plus, we will add the sync nop instruction after
each instruction to make sure that current instruction depends on the
previous instruction explicitly.

This option will help us to get a hint if something is missing or broken
in software scoreboard pass.

Signed-off-by: Sagar Ghuge <sagar.ghuge@intel.com>
Reviewed-by: Lionel Landwerlin <lionel.g.landwerlin@intel.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/21797>

src/intel/compiler/brw_fs_generator.cpp

@@ -30,6 +30,7 @@
 #include "brw_eu.h"
 #include "brw_fs.h"
 #include "brw_cfg.h"
+#include "dev/intel_debug.h"
 #include "util/mesa-sha1.h"
 #include "util/half_float.h"
 
@@ -2387,6 +2388,14 @@ fs_generator::generate_code(const cfg_t *cfg, int dispatch_width,
             brw_inst_set_no_dd_check(p->devinfo, last, inst->no_dd_check);
          }
       }
+
+      /* When enabled, insert sync NOP after every instruction and make sure
+       * that current instruction depends on the previous instruction.
+       */
+      if (INTEL_DEBUG(DEBUG_SWSB_STALL) && devinfo->ver >= 12) {
+         brw_set_default_swsb(p, tgl_swsb_regdist(1));
+         brw_SYNC(p, TGL_SYNC_NOP);
+      }
    }
 
    brw_set_uip_jip(p, start_offset);