[Mesa-dev] [PATCH 02/12] i965: Add an option to not generate the SIMD8 fragment shader

[Kristian Høgsberg]

For now, this can only be triggered with a new 'no8' INTEL_DEBUG option
and a new context flag.  We'll use the context flag later, but introducing
it now lets us bisect to this commit if it breaks something.

Signed-off-by: Kristian Høgsberg <krh at bitplanet.net>
---
 src/mesa/drivers/dri/i965/brw_context.h   |  2 ++
 src/mesa/drivers/dri/i965/brw_fs.cpp      | 14 ++++++++++++--
 src/mesa/drivers/dri/i965/gen7_wm_state.c |  4 ++--
 src/mesa/drivers/dri/i965/gen8_ps_state.c |  4 ++--
 src/mesa/drivers/dri/i965/intel_debug.c   |  1 +
 src/mesa/drivers/dri/i965/intel_debug.h   |  1 +
 6 files changed, 20 insertions(+), 6 deletions(-)

diff --git a/src/mesa/drivers/dri/i965/brw_context.h b/src/mesa/drivers/dri/i965/brw_context.h
index 1bbcf46..ab7d858 100644
--- a/src/mesa/drivers/dri/i965/brw_context.h
+++ b/src/mesa/drivers/dri/i965/brw_context.h
@@ -340,6 +340,7 @@ struct brw_wm_prog_data {
       /** @} */
    } binding_table;
 
+   bool no_8;
    bool dual_src_blend;
    bool uses_pos_offset;
    bool uses_omask;
@@ -1031,6 +1032,7 @@ struct brw_context
    bool has_compr4;
    bool has_negative_rhw_bug;
    bool has_pln;
+   bool no_simd8;
 
    /**
     * Some versions of Gen hardware don't do centroid interpolation correctly
diff --git a/src/mesa/drivers/dri/i965/brw_fs.cpp b/src/mesa/drivers/dri/i965/brw_fs.cpp
index bf95b57..061c32d 100644
--- a/src/mesa/drivers/dri/i965/brw_fs.cpp
+++ b/src/mesa/drivers/dri/i965/brw_fs.cpp
@@ -3230,15 +3230,25 @@ brw_wm_fs_emit(struct brw_context *brw,
       }
    }
 
+   exec_list *simd8_instructions;
+   int no_simd8 = (INTEL_DEBUG & DEBUG_NO8) || brw->no_simd8;
+   if (no_simd8 && simd16_instructions) {
+      simd8_instructions = NULL;
+      prog_data->no_8 = true;
+   } else {
+      simd8_instructions = &v.instructions;
+      prog_data->no_8 = false;
+   }
+
    const unsigned *assembly = NULL;
    if (brw->gen >= 8) {
       gen8_fs_generator g(brw, mem_ctx, key, prog_data, prog, fp, v.do_dual_src);
-      assembly = g.generate_assembly(&v.instructions, simd16_instructions,
+      assembly = g.generate_assembly(simd8_instructions, simd16_instructions,
                                      final_assembly_size);
    } else {
       fs_generator g(brw, mem_ctx, key, prog_data, prog, fp, v.do_dual_src,
                      v.runtime_check_aads_emit, INTEL_DEBUG & DEBUG_WM);
-      assembly = g.generate_assembly(&v.instructions, simd16_instructions,
+      assembly = g.generate_assembly(simd8_instructions, simd16_instructions,
                                      final_assembly_size);
    }
 
diff --git a/src/mesa/drivers/dri/i965/gen7_wm_state.c b/src/mesa/drivers/dri/i965/gen7_wm_state.c
index c03d19d..c3e9316 100644
--- a/src/mesa/drivers/dri/i965/gen7_wm_state.c
+++ b/src/mesa/drivers/dri/i965/gen7_wm_state.c
@@ -223,9 +223,9 @@ upload_ps_state(struct brw_context *brw)
       _mesa_get_min_invocations_per_fragment(ctx, brw->fragment_program, false);
    assert(min_inv_per_frag >= 1);
 
-   if (brw->wm.prog_data->prog_offset_16) {
+   if (brw->wm.prog_data->prog_offset_16 || brw->wm.prog_data->no_8) {
       dw4 |= GEN7_PS_16_DISPATCH_ENABLE;
-      if (min_inv_per_frag == 1) {
+      if (!brw->wm.prog_data->no_8 && min_inv_per_frag == 1) {
          dw4 |= GEN7_PS_8_DISPATCH_ENABLE;
          dw5 |= (brw->wm.prog_data->base.dispatch_grf_start_reg <<
                  GEN7_PS_DISPATCH_START_GRF_SHIFT_0);
diff --git a/src/mesa/drivers/dri/i965/gen8_ps_state.c b/src/mesa/drivers/dri/i965/gen8_ps_state.c
index f58d49c..49d4fe0 100644
--- a/src/mesa/drivers/dri/i965/gen8_ps_state.c
+++ b/src/mesa/drivers/dri/i965/gen8_ps_state.c
@@ -195,9 +195,9 @@ upload_ps_state(struct brw_context *brw)
       _mesa_get_min_invocations_per_fragment(ctx, brw->fragment_program, false);
    assert(min_invocations_per_fragment >= 1);
 
-   if (brw->wm.prog_data->prog_offset_16) {
+   if (brw->wm.prog_data->prog_offset_16 || brw->wm.prog_data->no_8) {
       dw6 |= GEN7_PS_16_DISPATCH_ENABLE;
-      if (min_invocations_per_fragment == 1) {
+      if (!brw->wm.prog_data->no_8 && min_invocations_per_fragment == 1) {
          dw6 |= GEN7_PS_8_DISPATCH_ENABLE;
          dw7 |= (brw->wm.prog_data->base.dispatch_grf_start_reg <<
                  GEN7_PS_DISPATCH_START_GRF_SHIFT_0);
diff --git a/src/mesa/drivers/dri/i965/intel_debug.c b/src/mesa/drivers/dri/i965/intel_debug.c
index c72fce2..1fb8b6c 100644
--- a/src/mesa/drivers/dri/i965/intel_debug.c
+++ b/src/mesa/drivers/dri/i965/intel_debug.c
@@ -66,6 +66,7 @@ static const struct dri_debug_control debug_control[] = {
    { "nodualobj", DEBUG_NO_DUAL_OBJECT_GS },
    { "optimizer", DEBUG_OPTIMIZER },
    { "noann", DEBUG_NO_ANNOTATION },
+   { "no8",  DEBUG_NO8 },
    { NULL,    0 }
 };
 
diff --git a/src/mesa/drivers/dri/i965/intel_debug.h b/src/mesa/drivers/dri/i965/intel_debug.h
index 37dc34a..8e1c299 100644
--- a/src/mesa/drivers/dri/i965/intel_debug.h
+++ b/src/mesa/drivers/dri/i965/intel_debug.h
@@ -62,6 +62,7 @@ extern uint64_t INTEL_DEBUG;
 #define DEBUG_NO_DUAL_OBJECT_GS 0x80000000
 #define DEBUG_OPTIMIZER   0x100000000
 #define DEBUG_NO_ANNOTATION 0x200000000
+#define DEBUG_NO8        0x40000000
 
 #ifdef HAVE_ANDROID_PLATFORM
 #define LOG_TAG "INTEL-MESA"
-- 
2.0.0