Revert "intel/compiler: make uses_pos_offset a tri-state"

This reverts commit 5489033fa8.

The problem I was trying to address is that we were programming the
3DSTATE_PS::PositionXYOffsetSelect bit differently with GPL (CENTROID)
than without (NONE).

I failed to understand that this bit also impacts the thread payload
layout. GPL fragment shaders don't know ahead of time if pos_offset is
going to be used. It'll be choosen at runtime base on push constant
bits. So we need to program this bit different just to have a payload
matching the compiled shader code.

This fixes the freedoom replay with GPL FS shader in SIMD32.

Signed-off-by: Lionel Landwerlin <lionel.g.landwerlin@intel.com>
Acked-by: Ivan Briano <ivan.briano@intel.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/22938>

src/gallium/drivers/crocus/crocus_state.c

@@ -6505,9 +6505,7 @@ crocus_upload_dirty_render_state(struct crocus_context *ice,
           * look useful at the moment.  We might need this in future.
           */
          ps.PositionXYOffsetSelect =
-            brw_wm_prog_data_uses_position_xy_offset(wm_prog_data,
+            wm_prog_data->uses_pos_offset ? POSOFFSET_SAMPLE : POSOFFSET_NONE;
-                                                     0 /* msaa_flags */) ?
-            POSOFFSET_SAMPLE : POSOFFSET_NONE;
 
          if (wm_prog_data->base.total_scratch) {
             struct crocus_bo *bo = crocus_get_scratch_space(ice, wm_prog_data->base.total_scratch, MESA_SHADER_FRAGMENT);
@@ -7274,10 +7272,10 @@ crocus_upload_dirty_render_state(struct crocus_context *ice,
        * We only require XY sample offsets. So, this recommendation doesn't
        * look useful at the moment. We might need this in future.
        */
-      wm.PositionXYOffsetSelect =
+      if (wm_prog_data->uses_pos_offset)
-         brw_wm_prog_data_uses_position_xy_offset(wm_prog_data,
+         wm.PositionXYOffsetSelect = POSOFFSET_SAMPLE;
-                                                  0 /* msaa_flags */) ?
+      else
-         POSOFFSET_SAMPLE : POSOFFSET_NONE;
+         wm.PositionXYOffsetSelect = POSOFFSET_NONE;
 #endif
          wm.LineStippleEnable = cso->cso.line_stipple_enable;
          wm.PolygonStippleEnable = cso->cso.poly_stipple_enable;

src/gallium/drivers/iris/iris_state.c

@@ -4936,9 +4936,7 @@ iris_store_fs_state(const struct intel_device_info *devinfo,
        * look useful at the moment.  We might need this in future.
        */
       ps.PositionXYOffsetSelect =
-         brw_wm_prog_data_uses_position_xy_offset(wm_prog_data,
+         wm_prog_data->uses_pos_offset ? POSOFFSET_SAMPLE : POSOFFSET_NONE;
-                                                  0 /* msaa_flags */) ?
-         POSOFFSET_SAMPLE : POSOFFSET_NONE;
 
       if (prog_data->total_scratch) {
          INIT_THREAD_SCRATCH_SIZE(ps);

src/intel/compiler/brw_compiler.h

@@ -923,8 +923,7 @@ struct brw_wm_prog_data {
    bool dispatch_16;
    bool dispatch_32;
    bool dual_src_blend;
-   enum brw_sometimes uses_pos_offset;
+   bool uses_pos_offset;
-   bool read_pos_offset_input;
    bool uses_omask;
    bool uses_kill;
    bool uses_src_depth;
@@ -1187,25 +1186,6 @@ brw_wm_prog_data_is_coarse(const struct brw_wm_prog_data *prog_data,
    return prog_data->coarse_pixel_dispatch;
 }
 
-static inline bool
-brw_wm_prog_data_uses_position_xy_offset(const struct brw_wm_prog_data *prog_data,
-                                         enum brw_wm_msaa_flags pushed_msaa_flags)
-{
-   bool per_sample;
-   if (pushed_msaa_flags & BRW_WM_MSAA_FLAG_ENABLE_DYNAMIC) {
-      per_sample = (pushed_msaa_flags & BRW_WM_MSAA_FLAG_PERSAMPLE_INTERP) != 0;
-   } else {
-      assert(prog_data->persample_dispatch == BRW_ALWAYS ||
-             prog_data->persample_dispatch == BRW_NEVER);
-      per_sample = prog_data->persample_dispatch == BRW_ALWAYS;
-   }
-
-   if (!per_sample)
-      return false;
-
-   return prog_data->read_pos_offset_input;
-}
-
 struct brw_push_const_block {
    unsigned dwords;     /* Dword count, not reg aligned */
    unsigned regs;

src/intel/compiler/brw_fs.cpp

@@ -7365,16 +7365,12 @@ brw_nir_populate_wm_prog_data(const nir_shader *shader,
        * per-sample dispatch.  If we need gl_SamplePosition and we don't have
        * persample dispatch, we hard-code it to 0.5.
        */
-      prog_data->read_pos_offset_input =
+      prog_data->uses_pos_offset =
-         BITSET_TEST(shader->info.system_values_read,
+         prog_data->persample_dispatch != BRW_NEVER &&
+         (BITSET_TEST(shader->info.system_values_read,
                       SYSTEM_VALUE_SAMPLE_POS) ||
           BITSET_TEST(shader->info.system_values_read,
-                     SYSTEM_VALUE_SAMPLE_POS_OR_CENTER);
+                      SYSTEM_VALUE_SAMPLE_POS_OR_CENTER));
-
-      if (prog_data->read_pos_offset_input)
-         prog_data->uses_pos_offset = prog_data->persample_dispatch;
-      else
-         prog_data->uses_pos_offset = BRW_NEVER;
    }
 
    prog_data->has_render_target_reads = shader->info.outputs_read != 0ull;

src/intel/vulkan/genX_pipeline.c

@@ -1535,10 +1535,8 @@ emit_3dstate_ps(struct anv_graphics_pipeline *pipeline,
       ps.PushConstantEnable         = wm_prog_data->base.nr_params > 0 ||
                                       wm_prog_data->base.ubo_ranges[0].length;
       ps.PositionXYOffsetSelect     =
-         !brw_wm_prog_data_uses_position_xy_offset(wm_prog_data,
+           !wm_prog_data->uses_pos_offset ? POSOFFSET_NONE :
-                                                   pipeline->fs_msaa_flags) ?
+           persample ? POSOFFSET_SAMPLE : POSOFFSET_CENTROID;
-         POSOFFSET_NONE :
-         (persample ? POSOFFSET_SAMPLE : POSOFFSET_CENTROID);
 
       ps.MaximumNumberofThreadsPerPSD = devinfo->max_threads_per_psd - 1;
 

src/intel/vulkan_hasvk/genX_pipeline.c

@@ -1695,10 +1695,8 @@ emit_3dstate_ps(struct anv_graphics_pipeline *pipeline,
       ps.BindingTableEntryCount     = fs_bin->bind_map.surface_count;
       ps.PushConstantEnable         = wm_prog_data->base.nr_params > 0 ||
                                       wm_prog_data->base.ubo_ranges[0].length;
-      ps.PositionXYOffsetSelect     =
+      ps.PositionXYOffsetSelect     = wm_prog_data->uses_pos_offset ?
-         brw_wm_prog_data_uses_position_xy_offset(wm_prog_data,
+                                      POSOFFSET_SAMPLE: POSOFFSET_NONE;
-                                                  0 /* msaa_flags */) ?
-         POSOFFSET_SAMPLE : POSOFFSET_NONE;
 #if GFX_VER < 8
       ps.AttributeEnable            = wm_prog_data->num_varying_inputs > 0;
       ps.oMaskPresenttoRenderTarget = wm_prog_data->uses_omask;