[Mesa-dev] [PATCH 13/14] nir: propagate bitsize information in nir_search

Jason Ekstrand jason at jlekstrand.net
Tue Mar 15 00:33:35 UTC 2016


On Mon, Mar 7, 2016 at 12:46 AM, Samuel Iglesias Gonsálvez <
siglesias at igalia.com> wrote:

> From: Connor Abbott <connor.w.abbott at intel.com>
>
> When we replace an expresion we have to compute bitsize information for the
> replacement. We do this in two passes to validate that bitsize information
> is consistent and correct: first we propagate bitsize from child nodes to
> parent, then we do it the other way around, starting from the original's
> instruction destination bitsize.
>
> v2 (Iago):
> - Always use nir_type_bool32 instead of nir_type_bool when generating
>   algebraic optimizations. Before we used nir_type_bool32 with constants
>   and nir_type_bool with variables.
> - Fix bool comparisons in nir_search.c to account for bitsized types.
>
> v3 (Sam):
> - Unpack the double constant value as unsigned long long (8 bytes) in
> nir_algrebraic.py.
>
> Signed-off-by: Iago Toral Quiroga <itoral at igalia.com>
> Signed-off-by: Samuel Iglesias Gonsálvez <siglesias at igalia.com>
> ---
>  src/compiler/nir/nir_algebraic.py |  22 +++-
>  src/compiler/nir/nir_search.c     | 244
> ++++++++++++++++++++++++++++++++++----
>  src/compiler/nir/nir_search.h     |   8 +-
>  3 files changed, 247 insertions(+), 27 deletions(-)
>
> diff --git a/src/compiler/nir/nir_algebraic.py
> b/src/compiler/nir/nir_algebraic.py
> index 2357b57..1818877 100644
> --- a/src/compiler/nir/nir_algebraic.py
> +++ b/src/compiler/nir/nir_algebraic.py
> @@ -63,11 +63,11 @@ class Value(object):
>  static const ${val.c_type} ${val.name} = {
>     { ${val.type_enum} },
>  % if isinstance(val, Constant):
> -   { ${hex(val)} /* ${val.value} */ },
> +   ${val.type()}, { ${hex(val)} /* ${val.value} */ },
>  % elif isinstance(val, Variable):
>     ${val.index}, /* ${val.var_name} */
>     ${'true' if val.is_constant else 'false'},
> -   nir_type_${ val.required_type or 'invalid' },
> +   ${val.type() or 'nir_type_invalid' },
>  % elif isinstance(val, Expression):
>     nir_op_${val.opcode},
>     { ${', '.join(src.c_ptr for src in val.sources)} },
> @@ -107,10 +107,18 @@ class Constant(Value):
>        if isinstance(self.value, (int, long)):
>           return hex(self.value)
>        elif isinstance(self.value, float):
> -         return hex(struct.unpack('I', struct.pack('f', self.value))[0])
> +         return hex(struct.unpack('Q', struct.pack('d', self.value))[0])
>        else:
>           assert False
>
> +   def type(self):
> +      if isinstance(self.value, (bool)):
> +         return "nir_type_bool32"
> +      elif isinstance(self.value, (int, long)):
> +         return "nir_type_int"
> +      elif isinstance(self.value, float):
> +         return "nir_type_float"
> +
>  _var_name_re =
> re.compile(r"(?P<const>#)?(?P<name>\w+)(?:@(?P<type>\w+))?")
>
>  class Variable(Value):
> @@ -129,6 +137,14 @@ class Variable(Value):
>
>        self.index = varset[self.var_name]
>
> +   def type(self):
> +      if self.required_type == 'bool':
> +         return "nir_type_bool32"
> +      elif self.required_type in ('int', 'unsigned'):
> +         return "nir_type_int"
> +      elif self.required_type == 'float':
> +         return "nir_type_float"
> +
>  class Expression(Value):
>     def __init__(self, expr, name_base, varset):
>        Value.__init__(self, name_base, "expression")
> diff --git a/src/compiler/nir/nir_search.c b/src/compiler/nir/nir_search.c
> index f509ce6..e874c79 100644
> --- a/src/compiler/nir/nir_search.c
> +++ b/src/compiler/nir/nir_search.c
> @@ -62,7 +62,8 @@ alu_instr_is_bool(nir_alu_instr *instr)
>     case nir_op_inot:
>        return src_is_bool(instr->src[0].src);
>     default:
> -      return nir_op_infos[instr->op].output_type == nir_type_bool;
> +      return (nir_op_infos[instr->op].output_type &
> NIR_ALU_TYPE_BASE_TYPE_MASK)
> +             == nir_type_bool;
>     }
>  }
>
> @@ -125,8 +126,10 @@ match_value(const nir_search_value *value,
> nir_alu_instr *instr, unsigned src,
>              nir_alu_instr *src_alu =
>                 nir_instr_as_alu(instr->src[src].src.ssa->parent_instr);
>
> -            if (nir_op_infos[src_alu->op].output_type != var->type &&
> -                !(var->type == nir_type_bool &&
> alu_instr_is_bool(src_alu)))
> +            if ((nir_op_infos[src_alu->op].output_type &
> +                 NIR_ALU_TYPE_BASE_TYPE_MASK) != var->type &&
> +                !((var->type & NIR_ALU_TYPE_BASE_TYPE_MASK) ==
> nir_type_bool &&
> +                  alu_instr_is_bool(src_alu)))
>                 return false;
>           }
>
> @@ -158,21 +161,65 @@ match_value(const nir_search_value *value,
> nir_alu_instr *instr, unsigned src,
>        nir_load_const_instr *load =
>           nir_instr_as_load_const(instr->src[src].src.ssa->parent_instr);
>
> -      switch (nir_op_infos[instr->op].input_types[src]) {
> +      switch (const_val->type) {
>        case nir_type_float:
>           for (unsigned i = 0; i < num_components; ++i) {
> -            if (load->value.f[new_swizzle[i]] != const_val->data.f)
> +            double val;
> +            switch (load->def.bit_size) {
> +            case 32:
> +               val = load->value.f[new_swizzle[i]];
> +               break;
> +            case 64:
> +               val = load->value.d[new_swizzle[i]];
> +               break;
> +            default:
> +               unreachable("unknown bit size");
> +            }
> +
> +            if (val != const_val->data.d)
>                 return false;
>           }
>           return true;
> +
>        case nir_type_int:
> +         for (unsigned i = 0; i < num_components; ++i) {
> +            int64_t val;
> +            switch (load->def.bit_size) {
> +            case 32:
> +               val = load->value.i[new_swizzle[i]];
> +               break;
> +            case 64:
> +               val = load->value.l[new_swizzle[i]];
> +               break;
> +            default:
> +               unreachable("unknown bit size");
> +            }
> +
> +            if (val != const_val->data.i)
> +               return false;
>
+         }
> +         return true;
> +
>        case nir_type_uint:
> -      case nir_type_bool:
> +      case nir_type_bool32:
>           for (unsigned i = 0; i < num_components; ++i) {
> -            if (load->value.i[new_swizzle[i]] != const_val->data.i)
> +            uint64_t val;
> +            switch (load->def.bit_size) {
> +            case 32:
> +               val = load->value.u[new_swizzle[i]];
> +               break;
> +            case 64:
> +               val = load->value.ul[new_swizzle[i]];
> +               break;
> +            default:
> +               unreachable("unknown bit size");
> +            }
> +
> +            if (val != const_val->data.u)
>                 return false;
>

64-bit.  Also, we may want bool to be its own case.  I think keeping it
with uint is probably fine.


>           }
>           return true;
> +
>        default:
>           unreachable("Invalid alu source type");
>        }
> @@ -244,9 +291,123 @@ match_expression(const nir_search_expression *expr,
> nir_alu_instr *instr,
>     }
>  }
>
> +typedef struct bitsize_tree {
> +   unsigned num_srcs;
> +   struct bitsize_tree *srcs[4];
> +
> +   unsigned common_size;
> +   bool is_src_sized[4];
> +   bool is_dest_sized;
> +
> +   unsigned dest_size;
> +   unsigned src_size[4];
> +} bitsize_tree;
> +
> +static bitsize_tree *
> +build_bitsize_tree(void *mem_ctx, struct match_state *state,
> +                   const nir_search_value *value)
> +{
> +   bitsize_tree *tree = ralloc(mem_ctx, bitsize_tree);
> +
> +   switch (value->type) {
> +   case nir_search_value_expression: {
> +      nir_search_expression *expr = nir_search_value_as_expression(value);
> +      nir_op_info info = nir_op_infos[expr->opcode];
> +      tree->num_srcs = info.num_inputs;
> +      tree->common_size = 0;
> +      for (unsigned i = 0; i < info.num_inputs; i++) {
> +         tree->is_src_sized[i] = !!(info.input_types[i] &
> NIR_ALU_TYPE_SIZE_MASK);
> +         if (tree->is_src_sized[i])
> +            tree->src_size[i] = info.input_types[i] &
> NIR_ALU_TYPE_SIZE_MASK;
> +         tree->srcs[i] = build_bitsize_tree(mem_ctx, state,
> expr->srcs[i]);
> +      }
> +      tree->is_dest_sized = !!(info.output_type & NIR_ALU_TYPE_SIZE_MASK);
> +      if (tree->is_dest_sized)
> +         tree->dest_size = info.output_type & NIR_ALU_TYPE_SIZE_MASK;
> +      break;
> +   }
> +
> +   case nir_search_value_variable: {
> +      nir_search_variable *var = nir_search_value_as_variable(value);
> +      tree->num_srcs = 0;
> +      tree->is_dest_sized = true;
> +      tree->dest_size =
> nir_src_bit_size(state->variables[var->variable].src);
> +      break;
> +   }
> +
> +   case nir_search_value_constant: {
> +      tree->num_srcs = 0;
> +      tree->is_dest_sized = false;
> +      tree->common_size = 0;
> +      break;
> +   }
> +   }
> +
> +   return tree;
> +}
> +
> +static unsigned
> +bitsize_tree_filter_up(bitsize_tree *tree)
> +{
> +   for (unsigned i = 0; i < tree->num_srcs; i++) {
> +      unsigned src_size = bitsize_tree_filter_up(tree->srcs[i]);
> +      if (src_size == 0)
> +         continue;
> +
> +      if (tree->is_src_sized[i]) {
> +         assert(src_size == tree->src_size[i]);
> +      } else if (tree->common_size != 0) {
> +         assert(src_size == tree->common_size);
> +         tree->src_size[i] = src_size;
> +      } else {
> +         tree->common_size = src_size;
> +         tree->src_size[i] = src_size;
> +      }
> +   }
> +
> +   if (tree->num_srcs && tree->common_size) {
> +      if (tree->dest_size == 0)
> +         tree->dest_size = tree->common_size;
> +      else if (!tree->is_dest_sized)
> +         assert(tree->dest_size == tree->common_size);
> +
> +      for (unsigned i = 0; i < tree->num_srcs; i++) {
> +         if (!tree->src_size[i])
> +            tree->src_size[i] = tree->common_size;
> +      }
> +   }
> +
> +   return tree->dest_size;
> +}
> +
> +static void
> +bitsize_tree_filter_down(bitsize_tree *tree, unsigned size)
> +{
> +   if (tree->dest_size)
> +      assert(tree->dest_size == size);
> +   else
> +      tree->dest_size = size;
> +
> +   if (!tree->is_dest_sized) {
> +      if (tree->common_size)
> +         assert(tree->common_size == size);
> +      else
> +         tree->common_size = size;
> +   }
> +
> +   for (unsigned i = 0; i < tree->num_srcs; i++) {
> +      if (!tree->src_size[i]) {
> +         assert(tree->common_size);
> +         tree->src_size[i] = tree->common_size;
> +      }
> +      bitsize_tree_filter_down(tree->srcs[i], tree->src_size[i]);
> +   }
> +}
>

Oh, man... This is so ugly...  Unfortunately, I know of no better way to do
it so we'll go with it.


> +
>  static nir_alu_src
> -construct_value(const nir_search_value *value, nir_alu_type type,
> -                unsigned num_components, struct match_state *state,
> +construct_value(const nir_search_value *value,
> +                unsigned num_components, bitsize_tree *bitsize,
> +                struct match_state *state,
>                  nir_instr *instr, void *mem_ctx)
>  {
>     switch (value->type) {
> @@ -257,7 +418,8 @@ construct_value(const nir_search_value *value,
> nir_alu_type type,
>           num_components = nir_op_infos[expr->opcode].output_size;
>
>        nir_alu_instr *alu = nir_alu_instr_create(mem_ctx, expr->opcode);
> -      nir_ssa_dest_init(&alu->instr, &alu->dest.dest, num_components, 32,
> NULL);
> +      nir_ssa_dest_init(&alu->instr, &alu->dest.dest, num_components,
> +                        bitsize->dest_size, NULL);
>        alu->dest.write_mask = (1 << num_components) - 1;
>        alu->dest.saturate = false;
>
> @@ -269,8 +431,7 @@ construct_value(const nir_search_value *value,
> nir_alu_type type,
>              num_components = nir_op_infos[alu->op].input_sizes[i];
>
>           alu->src[i] = construct_value(expr->srcs[i],
> -
>  nir_op_infos[alu->op].input_types[i],
> -                                       num_components,
> +                                       num_components, bitsize->srcs[i],
>                                         state, instr, mem_ctx);
>        }
>
> @@ -301,23 +462,57 @@ construct_value(const nir_search_value *value,
> nir_alu_type type,
>        const nir_search_constant *c = nir_search_value_as_constant(value);
>        nir_load_const_instr *load = nir_load_const_instr_create(mem_ctx,
> 1);
>
> -      switch (type) {
> +      switch (c->type) {
>
       case nir_type_float:
> -         load->def.name = ralloc_asprintf(mem_ctx, "%f", c->data.f);
> -         load->value.f[0] = c->data.f;
> +         load->def.name = ralloc_asprintf(mem_ctx, "%f", c->data.d);
> +         switch (bitsize->dest_size) {
> +         case 32:
> +            load->value.f[0] = c->data.d;
> +            break;
> +         case 64:
> +            load->value.d[0] = c->data.d;
> +            break;
> +         default:
> +            unreachable("unknown bit size");
> +         }
>           break;
> +
>        case nir_type_int:
> -         load->def.name = ralloc_asprintf(mem_ctx, "%d", c->data.i);
> -         load->value.i[0] = c->data.i;
> +         load->def.name = ralloc_asprintf(mem_ctx, "%ld", c->data.i);
> +         switch (bitsize->dest_size) {
> +         case 32:
> +            load->value.i[0] = c->data.i;
> +            break;
> +         case 64:
> +            load->value.l[0] = c->data.i;
> +            break;
> +         default:
> +            unreachable("unknown bit size");
> +         }
>           break;
> +
>        case nir_type_uint:
> -      case nir_type_bool:
> +         load->def.name = ralloc_asprintf(mem_ctx, "%lu", c->data.u);
> +         switch (bitsize->dest_size) {
> +         case 32:
> +            load->value.u[0] = c->data.u;
> +            break;
> +         case 64:
> +            load->value.ul[0] = c->data.u;
> +            break;
> +         default:
> +            unreachable("unknown bit size");
> +         }
> +
> +      case nir_type_bool32:
>           load->value.u[0] = c->data.u;
>           break;
>        default:
>           unreachable("Invalid alu source type");
>        }
>
> +      load->def.bit_size = bitsize->dest_size;
> +
>        nir_instr_insert_before(instr, &load->instr);
>
>        nir_alu_src val;
> @@ -352,6 +547,11 @@ nir_replace_instr(nir_alu_instr *instr, const
> nir_search_expression *search,
>                           swizzle, &state))
>        return NULL;
>
> +   void *bitsize_ctx = ralloc_context(NULL);
> +   bitsize_tree *tree = build_bitsize_tree(bitsize_ctx, &state, replace);
> +   bitsize_tree_filter_up(tree);
> +   bitsize_tree_filter_down(tree, instr->dest.dest.ssa.bit_size);
> +
>     /* Inserting a mov may be unnecessary.  However, it's much easier to
>      * simply let copy propagation clean this up than to try to go through
>      * and rewrite swizzles ourselves.
> @@ -362,9 +562,9 @@ nir_replace_instr(nir_alu_instr *instr, const
> nir_search_expression *search,
>                       instr->dest.dest.ssa.num_components,
>                       instr->dest.dest.ssa.bit_size, NULL);
>
> -   mov->src[0] = construct_value(replace,
> nir_op_infos[instr->op].output_type,
> -                                 instr->dest.dest.ssa.num_components,
> &state,
> -                                 &instr->instr, mem_ctx);
> +   mov->src[0] = construct_value(replace,
> +                                 instr->dest.dest.ssa.num_components,
> +                                 tree, &state, &instr->instr, mem_ctx);
>     nir_instr_insert_before(&instr->instr, &mov->instr);
>
>     nir_ssa_def_rewrite_uses(&instr->dest.dest.ssa,
> @@ -376,5 +576,7 @@ nir_replace_instr(nir_alu_instr *instr, const
> nir_search_expression *search,
>      */
>     nir_instr_remove(&instr->instr);
>
> +   ralloc_free(bitsize_ctx);
> +
>     return mov;
>  }
> diff --git a/src/compiler/nir/nir_search.h b/src/compiler/nir/nir_search.h
> index 7d47792..321d6d0 100644
> --- a/src/compiler/nir/nir_search.h
> +++ b/src/compiler/nir/nir_search.h
> @@ -71,10 +71,12 @@ typedef struct {
>  typedef struct {
>     nir_search_value value;
>
> +   nir_alu_type type;
> +
>     union {
> -      uint32_t u;
> -      int32_t i;
> -      float f;
> +      uint64_t u;
> +      int64_t i;
> +      double d;
>
    } data;
>  } nir_search_constant;
>
> --
> 2.7.0
>
> _______________________________________________
> mesa-dev mailing list
> mesa-dev at lists.freedesktop.org
> https://lists.freedesktop.org/mailman/listinfo/mesa-dev
>
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