1 files changed, 379 insertions, 0 deletions

diff --git a/src/compiler/nir/nir_search.c b/src/compiler/nir/nir_search.c
new file mode 100644
index 0000000..56d7e81
--- /dev/null
+++ b/src/compiler/nir/nir_search.c
@@ -0,0 +1,379 @@
+/*
+ * Copyright © 2014 Intel Corporation
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the "Software"),
+ * to deal in the Software without restriction, including without limitation
+ * the rights to use, copy, modify, merge, publish, distribute, sublicense,
+ * and/or sell copies of the Software, and to permit persons to whom the
+ * Software is furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice (including the next
+ * paragraph) shall be included in all copies or substantial portions of the
+ * Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
+ * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
+ * IN THE SOFTWARE.
+ *
+ * Authors:
+ *    Jason Ekstrand (jason@jlekstrand.net)
+ *
+ */
+
+#include "nir_search.h"
+
+struct match_state {
+   unsigned variables_seen;
+   nir_alu_src variables[NIR_SEARCH_MAX_VARIABLES];
+};
+
+static bool
+match_expression(const nir_search_expression *expr, nir_alu_instr *instr,
+                 unsigned num_components, const uint8_t *swizzle,
+                 struct match_state *state);
+
+static const uint8_t identity_swizzle[] = { 0, 1, 2, 3 };
+
+static bool alu_instr_is_bool(nir_alu_instr *instr);
+
+static bool
+src_is_bool(nir_src src)
+{
+   if (!src.is_ssa)
+      return false;
+   if (src.ssa->parent_instr->type != nir_instr_type_alu)
+      return false;
+   return alu_instr_is_bool(nir_instr_as_alu(src.ssa->parent_instr));
+}
+
+static bool
+alu_instr_is_bool(nir_alu_instr *instr)
+{
+   switch (instr->op) {
+   case nir_op_iand:
+   case nir_op_ior:
+   case nir_op_ixor:
+      return src_is_bool(instr->src[0].src) && src_is_bool(instr->src[1].src);
+   case nir_op_inot:
+      return src_is_bool(instr->src[0].src);
+   default:
+      return nir_op_infos[instr->op].output_type == nir_type_bool;
+   }
+}
+
+static bool
+match_value(const nir_search_value *value, nir_alu_instr *instr, unsigned src,
+            unsigned num_components, const uint8_t *swizzle,
+            struct match_state *state)
+{
+   uint8_t new_swizzle[4];
+
+   /* If the source is an explicitly sized source, then we need to reset
+    * both the number of components and the swizzle.
+    */
+   if (nir_op_infos[instr->op].input_sizes[src] != 0) {
+      num_components = nir_op_infos[instr->op].input_sizes[src];
+      swizzle = identity_swizzle;
+   }
+
+   for (unsigned i = 0; i < num_components; ++i)
+      new_swizzle[i] = instr->src[src].swizzle[swizzle[i]];
+
+   switch (value->type) {
+   case nir_search_value_expression:
+      if (!instr->src[src].src.is_ssa)
+         return false;
+
+      if (instr->src[src].src.ssa->parent_instr->type != nir_instr_type_alu)
+         return false;
+
+      return match_expression(nir_search_value_as_expression(value),
+                              nir_instr_as_alu(instr->src[src].src.ssa->parent_instr),
+                              num_components, new_swizzle, state);
+
+   case nir_search_value_variable: {
+      nir_search_variable *var = nir_search_value_as_variable(value);
+      assert(var->variable < NIR_SEARCH_MAX_VARIABLES);
+
+      if (state->variables_seen & (1 << var->variable)) {
+         if (!nir_srcs_equal(state->variables[var->variable].src,
+                             instr->src[src].src))
+            return false;
+
+         assert(!instr->src[src].abs && !instr->src[src].negate);
+
+         for (unsigned i = 0; i < num_components; ++i) {
+            if (state->variables[var->variable].swizzle[i] != new_swizzle[i])
+               return false;
+         }
+
+         return true;
+      } else {
+         if (var->is_constant &&
+             instr->src[src].src.ssa->parent_instr->type != nir_instr_type_load_const)
+            return false;
+
+         if (var->type != nir_type_invalid) {
+            if (instr->src[src].src.ssa->parent_instr->type != nir_instr_type_alu)
+               return false;
+
+            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)))
+               return false;
+         }
+
+         state->variables_seen |= (1 << var->variable);
+         state->variables[var->variable].src = instr->src[src].src;
+         state->variables[var->variable].abs = false;
+         state->variables[var->variable].negate = false;
+
+         for (unsigned i = 0; i < 4; ++i) {
+            if (i < num_components)
+               state->variables[var->variable].swizzle[i] = new_swizzle[i];
+            else
+               state->variables[var->variable].swizzle[i] = 0;
+         }
+
+         return true;
+      }
+   }
+
+   case nir_search_value_constant: {
+      nir_search_constant *const_val = nir_search_value_as_constant(value);
+
+      if (!instr->src[src].src.is_ssa)
+         return false;
+
+      if (instr->src[src].src.ssa->parent_instr->type != nir_instr_type_load_const)
+         return false;
+
+      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]) {
+      case nir_type_float:
+         for (unsigned i = 0; i < num_components; ++i) {
+            if (load->value.f[new_swizzle[i]] != const_val->data.f)
+               return false;
+         }
+         return true;
+      case nir_type_int:
+      case nir_type_uint:
+      case nir_type_bool:
+         for (unsigned i = 0; i < num_components; ++i) {
+            if (load->value.i[new_swizzle[i]] != const_val->data.i)
+               return false;
+         }
+         return true;
+      default:
+         unreachable("Invalid alu source type");
+      }
+   }
+
+   default:
+      unreachable("Invalid search value type");
+   }
+}
+
+static bool
+match_expression(const nir_search_expression *expr, nir_alu_instr *instr,
+                 unsigned num_components, const uint8_t *swizzle,
+                 struct match_state *state)
+{
+   if (instr->op != expr->opcode)
+      return false;
+
+   assert(!instr->dest.saturate);
+   assert(nir_op_infos[instr->op].num_inputs > 0);
+
+   /* If we have an explicitly sized destination, we can only handle the
+    * identity swizzle.  While dot(vec3(a, b, c).zxy) is a valid
+    * expression, we don't have the information right now to propagate that
+    * swizzle through.  We can only properly propagate swizzles if the
+    * instruction is vectorized.
+    */
+   if (nir_op_infos[instr->op].output_size != 0) {
+      for (unsigned i = 0; i < num_components; i++) {
+         if (swizzle[i] != i)
+            return false;
+      }
+   }
+
+   /* Stash off the current variables_seen bitmask.  This way we can
+    * restore it prior to matching in the commutative case below.
+    */
+   unsigned variables_seen_stash = state->variables_seen;
+
+   bool matched = true;
+   for (unsigned i = 0; i < nir_op_infos[instr->op].num_inputs; i++) {
+      if (!match_value(expr->srcs[i], instr, i, num_components,
+                       swizzle, state)) {
+         matched = false;
+         break;
+      }
+   }
+
+   if (matched)
+      return true;
+
+   if (nir_op_infos[instr->op].algebraic_properties & NIR_OP_IS_COMMUTATIVE) {
+      assert(nir_op_infos[instr->op].num_inputs == 2);
+
+      /* Restore the variables_seen bitmask.  If we don't do this, then we
+       * could end up with an erroneous failure due to variables found in the
+       * first match attempt above not matching those in the second.
+       */
+      state->variables_seen = variables_seen_stash;
+
+      if (!match_value(expr->srcs[0], instr, 1, num_components,
+                       swizzle, state))
+         return false;
+
+      return match_value(expr->srcs[1], instr, 0, num_components,
+                         swizzle, state);
+   } else {
+      return false;
+   }
+}
+
+static nir_alu_src
+construct_value(const nir_search_value *value, nir_alu_type type,
+                unsigned num_components, struct match_state *state,
+                nir_instr *instr, void *mem_ctx)
+{
+   switch (value->type) {
+   case nir_search_value_expression: {
+      const nir_search_expression *expr = nir_search_value_as_expression(value);
+
+      if (nir_op_infos[expr->opcode].output_size != 0)
+         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, NULL);
+      alu->dest.write_mask = (1 << num_components) - 1;
+      alu->dest.saturate = false;
+
+      for (unsigned i = 0; i < nir_op_infos[expr->opcode].num_inputs; i++) {
+         /* If the source is an explicitly sized source, then we need to reset
+          * the number of components to match.
+          */
+         if (nir_op_infos[alu->op].input_sizes[i] != 0)
+            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,
+                                       state, instr, mem_ctx);
+      }
+
+      nir_instr_insert_before(instr, &alu->instr);
+
+      nir_alu_src val;
+      val.src = nir_src_for_ssa(&alu->dest.dest.ssa);
+      val.negate = false;
+      val.abs = false,
+      memcpy(val.swizzle, identity_swizzle, sizeof val.swizzle);
+
+      return val;
+   }
+
+   case nir_search_value_variable: {
+      const nir_search_variable *var = nir_search_value_as_variable(value);
+      assert(state->variables_seen & (1 << var->variable));
+
+      nir_alu_src val = { NIR_SRC_INIT };
+      nir_alu_src_copy(&val, &state->variables[var->variable], mem_ctx);
+
+      assert(!var->is_constant);
+
+      return val;
+   }
+
+   case nir_search_value_constant: {
+      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) {
+      case nir_type_float:
+         load->def.name = ralloc_asprintf(mem_ctx, "%f", c->data.f);
+         load->value.f[0] = c->data.f;
+         break;
+      case nir_type_int:
+         load->def.name = ralloc_asprintf(mem_ctx, "%d", c->data.i);
+         load->value.i[0] = c->data.i;
+         break;
+      case nir_type_uint:
+      case nir_type_bool:
+         load->value.u[0] = c->data.u;
+         break;
+      default:
+         unreachable("Invalid alu source type");
+      }
+
+      nir_instr_insert_before(instr, &load->instr);
+
+      nir_alu_src val;
+      val.src = nir_src_for_ssa(&load->def);
+      val.negate = false;
+      val.abs = false,
+      memset(val.swizzle, 0, sizeof val.swizzle);
+
+      return val;
+   }
+
+   default:
+      unreachable("Invalid search value type");
+   }
+}
+
+nir_alu_instr *
+nir_replace_instr(nir_alu_instr *instr, const nir_search_expression *search,
+                  const nir_search_value *replace, void *mem_ctx)
+{
+   uint8_t swizzle[4] = { 0, 0, 0, 0 };
+
+   for (unsigned i = 0; i < instr->dest.dest.ssa.num_components; ++i)
+      swizzle[i] = i;
+
+   assert(instr->dest.dest.is_ssa);
+
+   struct match_state state;
+   state.variables_seen = 0;
+
+   if (!match_expression(search, instr, instr->dest.dest.ssa.num_components,
+                         swizzle, &state))
+      return NULL;
+
+   /* 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.
+    */
+   nir_alu_instr *mov = nir_alu_instr_create(mem_ctx, nir_op_imov);
+   mov->dest.write_mask = instr->dest.write_mask;
+   nir_ssa_dest_init(&mov->instr, &mov->dest.dest,
+                     instr->dest.dest.ssa.num_components, 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);
+   nir_instr_insert_before(&instr->instr, &mov->instr);
+
+   nir_ssa_def_rewrite_uses(&instr->dest.dest.ssa,
+                            nir_src_for_ssa(&mov->dest.dest.ssa));
+
+   /* We know this one has no more uses because we just rewrote them all,
+    * so we can remove it.  The rest of the matched expression, however, we
+    * don't know so much about.  We'll just let dead code clean them up.
+    */
+   nir_instr_remove(&instr->instr);
+
+   return mov;
+}