[Mesa-dev] [PATCH 18/27] i965/fs: Append ir_binop_ubo_load entries to the gather table

Abdiel Janulgue abdiel.janulgue at linux.intel.com
Tue Apr 28 13:08:15 PDT 2015


When the const block and offset are immediate values. Otherwise just
fall-back to the previous method of uploading the UBO constant data to
GRF using pull constants.

Signed-off-by: Abdiel Janulgue <abdiel.janulgue at linux.intel.com>
---
 src/mesa/drivers/dri/i965/brw_fs.cpp         | 11 ++++
 src/mesa/drivers/dri/i965/brw_fs.h           |  4 ++
 src/mesa/drivers/dri/i965/brw_fs_visitor.cpp | 86 +++++++++++++++++++++++++++-
 3 files changed, 100 insertions(+), 1 deletion(-)

diff --git a/src/mesa/drivers/dri/i965/brw_fs.cpp b/src/mesa/drivers/dri/i965/brw_fs.cpp
index 071ac59..031d807 100644
--- a/src/mesa/drivers/dri/i965/brw_fs.cpp
+++ b/src/mesa/drivers/dri/i965/brw_fs.cpp
@@ -2273,6 +2273,7 @@ fs_visitor::assign_constant_locations()
    }
 
    stage_prog_data->nr_params = 0;
+   stage_prog_data->nr_ubo_params = ubo_uniforms;
 
    unsigned const_reg_access[uniforms];
    memset(const_reg_access, 0, sizeof(const_reg_access));
@@ -2302,6 +2303,16 @@ fs_visitor::assign_constant_locations()
       stage_prog_data->gather_table[p].channel_mask =
          const_reg_access[i];
    }
+
+   for (unsigned i = 0; i < this->nr_ubo_gather_table; i++) {
+      int p = stage_prog_data->nr_gather_table++;
+      stage_prog_data->gather_table[p].reg = this->ubo_gather_table[i].reg;
+      stage_prog_data->gather_table[p].channel_mask = this->ubo_gather_table[i].channel_mask;
+      stage_prog_data->gather_table[p].const_block = this->ubo_gather_table[i].const_block;
+      stage_prog_data->gather_table[p].const_offset = this->ubo_gather_table[i].const_offset;
+      stage_prog_data->max_ubo_const_block = MAX2(stage_prog_data->max_ubo_const_block,
+                                                  this->ubo_gather_table[i].const_block);
+   }
 }
 
 /**
diff --git a/src/mesa/drivers/dri/i965/brw_fs.h b/src/mesa/drivers/dri/i965/brw_fs.h
index 32063f0..a48b2bb 100644
--- a/src/mesa/drivers/dri/i965/brw_fs.h
+++ b/src/mesa/drivers/dri/i965/brw_fs.h
@@ -417,6 +417,7 @@ public:
    void setup_uniform_values(ir_variable *ir);
    void setup_builtin_uniform_values(ir_variable *ir);
    int implied_mrf_writes(fs_inst *inst);
+   bool generate_ubo_gather_table(ir_expression* ir);
 
    virtual void dump_instructions();
    virtual void dump_instructions(const char *name);
@@ -445,6 +446,9 @@ public:
    /** Total number of direct uniforms we can get from NIR */
    unsigned num_direct_uniforms;
 
+   /** Number of ubo uniform variable components visited. */
+   unsigned ubo_uniforms;
+
    /** Byte-offset for the next available spot in the scratch space buffer. */
    unsigned last_scratch;
 
diff --git a/src/mesa/drivers/dri/i965/brw_fs_visitor.cpp b/src/mesa/drivers/dri/i965/brw_fs_visitor.cpp
index 4e99366..11e608b 100644
--- a/src/mesa/drivers/dri/i965/brw_fs_visitor.cpp
+++ b/src/mesa/drivers/dri/i965/brw_fs_visitor.cpp
@@ -1179,11 +1179,18 @@ fs_visitor::visit(ir_expression *ir)
       emit(FS_OPCODE_PACK_HALF_2x16_SPLIT, this->result, op[0], op[1]);
       break;
    case ir_binop_ubo_load: {
+      /* Use gather push constants if at all possible, otherwise just
+       * fall back to pull constants for UBOs
+       */
+      if (generate_ubo_gather_table(ir))
+         break;
+
       /* This IR node takes a constant uniform block and a constant or
        * variable byte offset within the block and loads a vector from that.
        */
       ir_constant *const_uniform_block = ir->operands[0]->as_constant();
       ir_constant *const_offset = ir->operands[1]->as_constant();
+
       fs_reg surf_index;
 
       if (const_uniform_block) {
@@ -4144,6 +4151,79 @@ fs_visitor::resolve_bool_comparison(ir_rvalue *rvalue, fs_reg *reg)
    *reg = neg_result;
 }
 
+bool
+fs_visitor::generate_ubo_gather_table(ir_expression *ir)
+{
+   ir_constant *const_uniform_block = ir->operands[0]->as_constant();
+   ir_constant *const_offset = ir->operands[1]->as_constant();
+
+   if (ir->operation != ir_binop_ubo_load ||
+       !brw->has_resource_streamer        ||
+       !brw->fs_ubo_gather                ||
+       !const_uniform_block               ||
+       !const_offset)
+      return false;
+
+  /* Only allow 16 registers (128 uniform components) as push constants.
+   */
+   unsigned int max_push_components = 16 * 8;
+   unsigned param_index = uniforms + ubo_uniforms;
+   if ((param_index + ir->type->vector_elements) >= max_push_components)
+      return false;
+
+   fs_reg reg;
+   if (dispatch_width == 16) {
+      for (int i = 0; i < (int) this->nr_ubo_gather_table; i++) {
+         if ((this->ubo_gather_table[i].const_block ==
+              const_uniform_block->value.u[0]) &&
+             (this->ubo_gather_table[i].const_offset ==
+              const_offset->value.u[0])) {
+            reg = fs_reg(UNIFORM, this->ubo_gather_table[i].reg);
+            reg.type = brw_type_for_base_type(ir->type);
+            break;
+         }
+      }
+      assert(reg.file == UNIFORM);
+   }
+
+   if (reg.file != UNIFORM) {
+      reg = fs_reg(UNIFORM, param_index);
+      int gather = this->nr_ubo_gather_table++;
+
+      assert(ir->type->vector_elements <= 4);
+      ubo_uniforms += ir->type->vector_elements;
+      this->ubo_gather_table[gather].reg = reg.reg;
+      this->ubo_gather_table[gather].const_block =
+         const_uniform_block->value.u[0];
+      this->ubo_gather_table[gather].const_offset =
+         const_offset->value.u[0];
+      reg.type = brw_type_for_base_type(ir->type);
+   }
+
+   if (ir->type->base_type == GLSL_TYPE_BOOL) {
+
+      for (int i = 0; i < ir->type->vector_elements; i++) {
+
+         /* The std140 packing rules don't allow vectors to cross 16-byte
+          * boundaries, and a reg is 32 bytes.
+          */
+         assert(reg.subreg_offset < 32);
+
+         /* UBO bools are any nonzero value.  We consider bools to be
+          * values with the low bit set to 1.  Convert them using CMP.
+          */
+         emit(CMP(result, reg, fs_reg(0u), BRW_CONDITIONAL_NZ));
+
+         result = offset(result, 1);
+      }
+      result.reg_offset = 0;
+   } else {
+      result = reg;
+   }
+
+   return true;
+}
+
 fs_visitor::fs_visitor(struct brw_context *brw,
                        void *mem_ctx,
                        const struct brw_wm_prog_key *key,
@@ -4224,6 +4304,7 @@ fs_visitor::init()
    this->regs_live_at_ip = NULL;
 
    this->uniforms = 0;
+   this->ubo_uniforms = 0;
    this->last_scratch = 0;
    this->pull_constant_loc = NULL;
    this->push_constant_loc = NULL;
@@ -4231,8 +4312,11 @@ fs_visitor::init()
    this->spilled_any_registers = false;
    this->do_dual_src = false;
 
-   if (dispatch_width == 8)
+   if (dispatch_width == 8) {
       this->param_size = rzalloc_array(mem_ctx, int, stage_prog_data->nr_params);
+      this->ubo_gather_table = rzalloc_array(mem_ctx, backend_visitor::gather_table,
+                                             stage_prog_data->nr_params);
+   }
 }
 
 fs_visitor::~fs_visitor()
-- 
1.9.1



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