[Mesa-dev] [PATCH 6/8] i965: enable varying component packing for BDW+

[Timothy Arceri]

shader-db results BDW:

total instructions in shared programs: 13192895 -> 13182437 (-0.08%)
instructions in affected programs: 827145 -> 816687 (-1.26%)
helped: 5199
HURT: 116

total cycles in shared programs: 539249342 -> 539156566 (-0.02%)
cycles in affected programs: 21894552 -> 21801776 (-0.42%)
helped: 10667
HURT: 7196

LOST:   0
GAINED: 17
---
 src/mesa/drivers/dri/i965/brw_link.cpp | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/src/mesa/drivers/dri/i965/brw_link.cpp b/src/mesa/drivers/dri/i965/brw_link.cpp
index 465cab767d..e9cf88dc86 100644
--- a/src/mesa/drivers/dri/i965/brw_link.cpp
+++ b/src/mesa/drivers/dri/i965/brw_link.cpp
@@ -297,40 +297,47 @@ brw_link_shader(struct gl_context *ctx, struct gl_shader_program *shProg)
           if (shProg->_LinkedShaders[i] == NULL)
              continue;
 
           brw_nir_link_shaders(compiler,
                                &shProg->_LinkedShaders[i]->Program->nir,
                                &shProg->_LinkedShaders[next]->Program->nir);
           next = i;
        }
     }
 
+   int prev = -1;
    for (stage = 0; stage < ARRAY_SIZE(shProg->_LinkedShaders); stage++) {
       struct gl_linked_shader *shader = shProg->_LinkedShaders[stage];
       if (!shader)
          continue;
 
       struct gl_program *prog = shader->Program;
       brw_shader_gather_info(prog->nir, prog);
 
       NIR_PASS_V(prog->nir, nir_lower_samplers, shProg);
       NIR_PASS_V(prog->nir, nir_lower_atomics, shProg);
 
       if (brw->ctx.Cache) {
          struct blob writer;
          blob_init(&writer);
          nir_serialize(&writer, prog->nir);
          prog->driver_cache_blob = ralloc_size(NULL, writer.size);
          memcpy(prog->driver_cache_blob, writer.data, writer.size);
          prog->driver_cache_blob_size = writer.size;
       }
 
+      if (brw->screen->devinfo.gen >= 8 && prev != -1) {
+         nir_compact_varyings(shProg->_LinkedShaders[prev]->Program->nir,
+                              prog->nir, ctx->API != API_OPENGL_COMPAT);
+      }
+      prev = stage;
+
       infos[stage] = &prog->nir->info;
 
       /* Make a pass over the IR to add state references for any built-in
        * uniforms that are used.  This has to be done now (during linking).
        * Code generation doesn't happen until the first time this shader is
        * used for rendering.  Waiting until then to generate the parameters is
        * too late.  At that point, the values for the built-in uniforms won't
        * get sent to the shader.
        */
       nir_foreach_variable(var, &prog->nir->uniforms) {
-- 
2.14.3