radeonsi: enable uniform propagation for varyings except VP/Energy

It regresses performance of VP/Energy.

Acked-by: Pierre-Eric Pelloux-Prayer <pierre-eric.pelloux-prayer@amd.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/26819>

3 files changed, 139 insertions, 0 deletions

diff --git a/src/gallium/drivers/radeonsi/si_get.c b/src/gallium/drivers/radeonsi/si_get.c
index c2fc213d9d7..8a3dbda96de 100644
--- a/src/gallium/drivers/radeonsi/si_get.c
+++ b/src/gallium/drivers/radeonsi/si_get.c
@@ -1339,6 +1339,137 @@ static int si_get_screen_fd(struct pipe_screen *screen)
    return ws->get_fd(ws);
 }
 
+static unsigned si_varying_expression_max_cost(nir_shader *producer, nir_shader *consumer)
+{
+   unsigned num_profiles = si_get_num_shader_profiles();
+
+   for (unsigned i = 0; i < num_profiles; i++) {
+      if (_mesa_printed_sha1_equal(consumer->info.source_sha1, si_shader_profiles[i].sha1)) {
+         if (si_shader_profiles[i].options & SI_PROFILE_NO_OPT_UNIFORM_VARYINGS)
+            return 0; /* only propagate constants */
+         break;
+      }
+   }
+
+   switch (consumer->info.stage) {
+   case MESA_SHADER_TESS_CTRL: /* VS->TCS */
+      /* Non-amplifying shaders can always have their variyng expressions
+       * moved into later shaders.
+       */
+      return UINT_MAX;
+
+   case MESA_SHADER_GEOMETRY: /* VS->GS, TES->GS */
+      return consumer->info.gs.vertices_in == 1 ? UINT_MAX :
+             consumer->info.gs.vertices_in == 2 ? 20 : 14;
+
+   case MESA_SHADER_TESS_EVAL: /* VS->TES, TCS->TES */
+   case MESA_SHADER_FRAGMENT:
+      /* Up to 3 uniforms and 5 ALUs. */
+      return 14;
+
+   default:
+      unreachable("unexpected shader stage");
+   }
+}
+
+static unsigned si_varying_estimate_instr_cost(nir_instr *instr)
+{
+   unsigned dst_bit_size, src_bit_size, num_dst_dwords;
+   nir_op alu_op;
+
+   /* This is a very loose approximation based on gfx10. */
+   switch (instr->type) {
+   case nir_instr_type_alu:
+      dst_bit_size = nir_instr_as_alu(instr)->def.bit_size;
+      src_bit_size = nir_instr_as_alu(instr)->src[0].src.ssa->bit_size;
+      alu_op = nir_instr_as_alu(instr)->op;
+      num_dst_dwords = DIV_ROUND_UP(dst_bit_size, 32);
+
+      switch (alu_op) {
+      case nir_op_mov:
+      case nir_op_vec2:
+      case nir_op_vec3:
+      case nir_op_vec4:
+      case nir_op_vec5:
+      case nir_op_vec8:
+      case nir_op_vec16:
+      case nir_op_fabs:
+      case nir_op_fneg:
+      case nir_op_fsat:
+         return 0;
+
+      case nir_op_imul:
+      case nir_op_umul_low:
+         return dst_bit_size <= 16 ? 1 : 4 * num_dst_dwords;
+
+      case nir_op_imul_high:
+      case nir_op_umul_high:
+      case nir_op_imul_2x32_64:
+      case nir_op_umul_2x32_64:
+         return 4;
+
+      case nir_op_fexp2:
+      case nir_op_flog2:
+      case nir_op_frcp:
+      case nir_op_frsq:
+      case nir_op_fsqrt:
+      case nir_op_fsin:
+      case nir_op_fcos:
+      case nir_op_fsin_amd:
+      case nir_op_fcos_amd:
+         return 4; /* FP16 & FP32. */
+
+      case nir_op_fpow:
+         return 4 + 1 + 4; /* log2 + mul + exp2 */
+
+      case nir_op_fsign:
+         return dst_bit_size == 64 ? 4 : 3; /* See ac_build_fsign. */
+
+      case nir_op_idiv:
+      case nir_op_udiv:
+      case nir_op_imod:
+      case nir_op_umod:
+      case nir_op_irem:
+         return dst_bit_size == 64 ? 80 : 40;
+
+      case nir_op_fdiv:
+         return dst_bit_size == 64 ? 80 : 5; /* FP16 & FP32: rcp + mul */
+
+      case nir_op_fmod:
+      case nir_op_frem:
+         return dst_bit_size == 64 ? 80 : 8;
+
+      default:
+         /* Double opcodes. Comparisons have always full performance. */
+         if ((dst_bit_size == 64 &&
+              nir_op_infos[alu_op].output_type & nir_type_float) ||
+             (dst_bit_size >= 8 && src_bit_size == 64 &&
+              nir_op_infos[alu_op].input_types[0] & nir_type_float))
+            return 16;
+
+         return DIV_ROUND_UP(MAX2(dst_bit_size, src_bit_size), 32);
+      }
+
+   case nir_instr_type_intrinsic:
+      dst_bit_size = nir_instr_as_intrinsic(instr)->def.bit_size;
+      num_dst_dwords = DIV_ROUND_UP(dst_bit_size, 32);
+
+      switch (nir_instr_as_intrinsic(instr)->intrinsic) {
+      case nir_intrinsic_load_deref:
+         /* Uniform or UBO load.
+          * Set a low cost to balance the number of scalar loads and ALUs.
+          */
+         return 3 * num_dst_dwords;
+
+      default:
+         unreachable("unexpected intrinsic");
+      }
+
+   default:
+      unreachable("unexpected instr type");
+   }
+}
+
 void si_init_screen_get_functions(struct si_screen *sscreen)
 {
    sscreen->b.get_name = si_get_name;
@@ -1439,4 +1570,6 @@ void si_init_screen_get_functions(struct si_screen *sscreen)
    options->support_indirect_inputs = BITFIELD_BIT(MESA_SHADER_TESS_CTRL) |
                                       BITFIELD_BIT(MESA_SHADER_TESS_EVAL);
    options->support_indirect_outputs = BITFIELD_BIT(MESA_SHADER_TESS_CTRL);
+   options->varying_expression_max_cost = si_varying_expression_max_cost;
+   options->varying_estimate_instr_cost = si_varying_estimate_instr_cost;
 }
diff --git a/src/gallium/drivers/radeonsi/si_shader.h b/src/gallium/drivers/radeonsi/si_shader.h
index 6fb351fa30d..44e7dca11ce 100644
--- a/src/gallium/drivers/radeonsi/si_shader.h
+++ b/src/gallium/drivers/radeonsi/si_shader.h
@@ -326,6 +326,7 @@ unsigned si_get_num_shader_profiles(void);
 #define SI_PROFILE_VS_NO_BINNING             (1 << 3)
 #define SI_PROFILE_GFX9_GFX10_PS_NO_BINNING  (1 << 4)
 #define SI_PROFILE_CLAMP_DIV_BY_ZERO         (1 << 5)
+#define SI_PROFILE_NO_OPT_UNIFORM_VARYINGS   (1 << 6)
 
 enum si_shader_dump_type {
    SI_DUMP_SHADER_KEY,
diff --git a/src/gallium/drivers/radeonsi/si_shader_info.c b/src/gallium/drivers/radeonsi/si_shader_info.c
index 09b00aaf2a7..e446ac081df 100644
--- a/src/gallium/drivers/radeonsi/si_shader_info.c
+++ b/src/gallium/drivers/radeonsi/si_shader_info.c
@@ -18,6 +18,11 @@ struct si_shader_profile si_shader_profiles[] =
       SI_PROFILE_VS_NO_BINNING,
    },
    {
+      /* Viewperf/Energy */
+      {0x17118671, 0xd0102e0c, 0x947f3592, 0xb2057e7b, 0x4da5d9b0},
+      SI_PROFILE_NO_OPT_UNIFORM_VARYINGS,    /* Uniform propagation regresses performance. */
+   },
+   {
       /* Viewperf/Medical */
       {0x4dce4331, 0x38f778d5, 0x1b75a717, 0x3e454fb9, 0xeb1527f0},
       SI_PROFILE_GFX9_GFX10_PS_NO_BINNING,