libX11 libXinerama mesa git update 1 Feb 2011

1 files changed, 425 insertions, 424 deletions

diff --git a/mesalib/src/glsl/opt_function_inlining.cpp b/mesalib/src/glsl/opt_function_inlining.cpp
index 83197e11a..2e7831dcb 100644
--- a/mesalib/src/glsl/opt_function_inlining.cpp
+++ b/mesalib/src/glsl/opt_function_inlining.cpp
@@ -1,424 +1,425 @@
-/*

- * Copyright © 2010 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.

- */

-

-/**

- * \file opt_function_inlining.cpp

- *

- * Replaces calls to functions with the body of the function.

- */

-

-#include <inttypes.h>

-#include "ir.h"

-#include "ir_visitor.h"

-#include "ir_function_inlining.h"

-#include "ir_expression_flattening.h"

-#include "glsl_types.h"

-#include "program/hash_table.h"

-

-static void

-do_sampler_replacement(exec_list *instructions,

-		       ir_variable *sampler,

-		       ir_dereference *deref);

-

-class ir_function_inlining_visitor : public ir_hierarchical_visitor {

-public:

-   ir_function_inlining_visitor()

-   {

-      progress = false;

-   }

-

-   virtual ~ir_function_inlining_visitor()

-   {

-      /* empty */

-   }

-

-   virtual ir_visitor_status visit_enter(ir_expression *);

-   virtual ir_visitor_status visit_enter(ir_call *);

-   virtual ir_visitor_status visit_enter(ir_assignment *);

-   virtual ir_visitor_status visit_enter(ir_return *);

-   virtual ir_visitor_status visit_enter(ir_texture *);

-   virtual ir_visitor_status visit_enter(ir_swizzle *);

-

-   bool progress;

-};

-

-

-bool

-automatic_inlining_predicate(ir_instruction *ir)

-{

-   ir_call *call = ir->as_call();

-

-   if (call && can_inline(call))

-      return true;

-

-   return false;

-}

-

-bool

-do_function_inlining(exec_list *instructions)

-{

-   ir_function_inlining_visitor v;

-

-   do_expression_flattening(instructions, automatic_inlining_predicate);

-

-   v.run(instructions);

-

-   return v.progress;

-}

-

-static void

-replace_return_with_assignment(ir_instruction *ir, void *data)

-{

-   void *ctx = talloc_parent(ir);

-   ir_variable *retval = (ir_variable *)data;

-   ir_return *ret = ir->as_return();

-

-   if (ret) {

-      if (ret->value) {

-	 ir_rvalue *lhs = new(ctx) ir_dereference_variable(retval);

-	 ret->replace_with(new(ctx) ir_assignment(lhs, ret->value, NULL));

-      } else {

-	 /* un-valued return has to be the last return, or we shouldn't

-	  * have reached here. (see can_inline()).

-	  */

-	 assert(ret->next->is_tail_sentinel());

-	 ret->remove();

-      }

-   }

-}

-

-ir_rvalue *

-ir_call::generate_inline(ir_instruction *next_ir)

-{

-   void *ctx = talloc_parent(this);

-   ir_variable **parameters;

-   int num_parameters;

-   int i;

-   ir_variable *retval = NULL;

-   struct hash_table *ht;

-

-   ht = hash_table_ctor(0, hash_table_pointer_hash, hash_table_pointer_compare);

-

-   num_parameters = 0;

-   foreach_iter(exec_list_iterator, iter_sig, this->callee->parameters)

-      num_parameters++;

-

-   parameters = new ir_variable *[num_parameters];

-

-   /* Generate storage for the return value. */

-   if (this->callee->return_type) {

-      retval = new(ctx) ir_variable(this->callee->return_type, "_ret_val",

-				    ir_var_auto);

-      next_ir->insert_before(retval);

-   }

-

-   /* Generate the declarations for the parameters to our inlined code,

-    * and set up the mapping of real function body variables to ours.

-    */

-   i = 0;

-   exec_list_iterator sig_param_iter = this->callee->parameters.iterator();

-   exec_list_iterator param_iter = this->actual_parameters.iterator();

-   for (i = 0; i < num_parameters; i++) {

-      ir_variable *sig_param = (ir_variable *) sig_param_iter.get();

-      ir_rvalue *param = (ir_rvalue *) param_iter.get();

-

-      /* Generate a new variable for the parameter. */

-      if (sig_param->type->base_type == GLSL_TYPE_SAMPLER) {

-	 /* For samplers, we want the inlined sampler references

-	  * referencing the passed in sampler variable, since that

-	  * will have the location information, which an assignment of

-	  * a sampler wouldn't.  Fix it up below.

-	  */

-	 parameters[i] = NULL;

-      } else {

-	 parameters[i] = sig_param->clone(ctx, ht);

-	 parameters[i]->mode = ir_var_auto;

-

-	 /* Remove the read-only decoration becuase we're going to write

-	  * directly to this variable.  If the cloned variable is left

-	  * read-only and the inlined function is inside a loop, the loop

-	  * analysis code will get confused.

-	  */

-	 parameters[i]->read_only = false;

-	 next_ir->insert_before(parameters[i]);

-      }

-

-      /* Move the actual param into our param variable if it's an 'in' type. */

-      if (parameters[i] && (sig_param->mode == ir_var_in ||

-			    sig_param->mode == ir_var_inout)) {

-	 ir_assignment *assign;

-

-	 assign = new(ctx) ir_assignment(new(ctx) ir_dereference_variable(parameters[i]),

-					 param, NULL);

-	 next_ir->insert_before(assign);

-      }

-

-      sig_param_iter.next();

-      param_iter.next();

-   }

-

-   exec_list new_instructions;

-

-   /* Generate the inlined body of the function to a new list */

-   foreach_iter(exec_list_iterator, iter, callee->body) {

-      ir_instruction *ir = (ir_instruction *)iter.get();

-      ir_instruction *new_ir = ir->clone(ctx, ht);

-

-      new_instructions.push_tail(new_ir);

-      visit_tree(new_ir, replace_return_with_assignment, retval);

-   }

-

-   /* If any samplers were passed in, replace any deref of the sampler

-    * with a deref of the sampler argument.

-    */

-   param_iter = this->actual_parameters.iterator();

-   sig_param_iter = this->callee->parameters.iterator();

-   for (i = 0; i < num_parameters; i++) {

-      ir_instruction *const param = (ir_instruction *) param_iter.get();

-      ir_variable *sig_param = (ir_variable *) sig_param_iter.get();

-

-      if (sig_param->type->base_type == GLSL_TYPE_SAMPLER) {

-	 ir_dereference *deref = param->as_dereference();

-

-	 assert(deref);

-	 do_sampler_replacement(&new_instructions, sig_param, deref);

-      }

-      param_iter.next();

-      sig_param_iter.next();

-   }

-

-   /* Now push those new instructions in. */

-   foreach_iter(exec_list_iterator, iter, new_instructions) {

-      ir_instruction *ir = (ir_instruction *)iter.get();

-      next_ir->insert_before(ir);

-   }

-

-   /* Copy back the value of any 'out' parameters from the function body

-    * variables to our own.

-    */

-   i = 0;

-   param_iter = this->actual_parameters.iterator();

-   sig_param_iter = this->callee->parameters.iterator();

-   for (i = 0; i < num_parameters; i++) {

-      ir_instruction *const param = (ir_instruction *) param_iter.get();

-      const ir_variable *const sig_param = (ir_variable *) sig_param_iter.get();

-

-      /* Move our param variable into the actual param if it's an 'out' type. */

-      if (parameters[i] && (sig_param->mode == ir_var_out ||

-			    sig_param->mode == ir_var_inout)) {

-	 ir_assignment *assign;

-

-	 assign = new(ctx) ir_assignment(param->clone(ctx, NULL)->as_rvalue(),

-					 new(ctx) ir_dereference_variable(parameters[i]),

-					 NULL);

-	 next_ir->insert_before(assign);

-      }

-

-      param_iter.next();

-      sig_param_iter.next();

-   }

-

-   delete [] parameters;

-

-   hash_table_dtor(ht);

-

-   if (retval)

-      return new(ctx) ir_dereference_variable(retval);

-   else

-      return NULL;

-}

-

-

-ir_visitor_status

-ir_function_inlining_visitor::visit_enter(ir_expression *ir)

-{

-   (void) ir;

-   return visit_continue_with_parent;

-}

-

-

-ir_visitor_status

-ir_function_inlining_visitor::visit_enter(ir_return *ir)

-{

-   (void) ir;

-   return visit_continue_with_parent;

-}

-

-

-ir_visitor_status

-ir_function_inlining_visitor::visit_enter(ir_texture *ir)

-{

-   (void) ir;

-   return visit_continue_with_parent;

-}

-

-

-ir_visitor_status

-ir_function_inlining_visitor::visit_enter(ir_swizzle *ir)

-{

-   (void) ir;

-   return visit_continue_with_parent;

-}

-

-

-ir_visitor_status

-ir_function_inlining_visitor::visit_enter(ir_call *ir)

-{

-   if (can_inline(ir)) {

-      /* If the call was part of some tree, then it should have been

-       * flattened out or we shouldn't have seen it because of a

-       * visit_continue_with_parent in this visitor.

-       */

-      assert(ir == base_ir);

-

-      (void) ir->generate_inline(ir);

-      ir->remove();

-      this->progress = true;

-   }

-

-   return visit_continue;

-}

-

-

-ir_visitor_status

-ir_function_inlining_visitor::visit_enter(ir_assignment *ir)

-{

-   ir_call *call = ir->rhs->as_call();

-   if (!call || !can_inline(call))

-      return visit_continue;

-

-   /* generates the parameter setup, function body, and returns the return

-    * value of the function

-    */

-   ir_rvalue *rhs = call->generate_inline(ir);

-   assert(rhs);

-

-   ir->rhs = rhs;

-   this->progress = true;

-

-   return visit_continue;

-}

-

-/**

- * Replaces references to the "sampler" variable with a clone of "deref."

- *

- * From the spec, samplers can appear in the tree as function

- * (non-out) parameters and as the result of array indexing and

- * structure field selection.  In our builtin implementation, they

- * also appear in the sampler field of an ir_tex instruction.

- */

-

-class ir_sampler_replacement_visitor : public ir_hierarchical_visitor {

-public:

-   ir_sampler_replacement_visitor(ir_variable *sampler, ir_dereference *deref)

-   {

-      this->sampler = sampler;

-      this->deref = deref;

-   }

-

-   virtual ~ir_sampler_replacement_visitor()

-   {

-   }

-

-   virtual ir_visitor_status visit_leave(ir_call *);

-   virtual ir_visitor_status visit_leave(ir_dereference_array *);

-   virtual ir_visitor_status visit_leave(ir_dereference_record *);

-   virtual ir_visitor_status visit_leave(ir_texture *);

-

-   void replace_deref(ir_dereference **deref);

-   void replace_rvalue(ir_rvalue **rvalue);

-

-   ir_variable *sampler;

-   ir_dereference *deref;

-};

-

-void

-ir_sampler_replacement_visitor::replace_deref(ir_dereference **deref)

-{

-   ir_dereference_variable *deref_var = (*deref)->as_dereference_variable();

-   if (deref_var && deref_var->var == this->sampler) {

-      *deref = this->deref->clone(talloc_parent(*deref), NULL);

-   }

-}

-

-void

-ir_sampler_replacement_visitor::replace_rvalue(ir_rvalue **rvalue)

-{

-   if (!*rvalue)

-      return;

-

-   ir_dereference *deref = (*rvalue)->as_dereference();

-

-   if (!deref)

-      return;

-

-   replace_deref(&deref);

-   *rvalue = deref;

-}

-

-ir_visitor_status

-ir_sampler_replacement_visitor::visit_leave(ir_texture *ir)

-{

-   replace_deref(&ir->sampler);

-

-   return visit_continue;

-}

-

-ir_visitor_status

-ir_sampler_replacement_visitor::visit_leave(ir_dereference_array *ir)

-{

-   replace_rvalue(&ir->array);

-   return visit_continue;

-}

-

-ir_visitor_status

-ir_sampler_replacement_visitor::visit_leave(ir_dereference_record *ir)

-{

-   replace_rvalue(&ir->record);

-   return visit_continue;

-}

-

-ir_visitor_status

-ir_sampler_replacement_visitor::visit_leave(ir_call *ir)

-{

-   foreach_iter(exec_list_iterator, iter, *ir) {

-      ir_rvalue *param = (ir_rvalue *)iter.get();

-      ir_rvalue *new_param = param;

-      replace_rvalue(&new_param);

-

-      if (new_param != param) {

-	 param->replace_with(new_param);

-      }

-   }

-   return visit_continue;

-}

-

-static void

-do_sampler_replacement(exec_list *instructions,

-		       ir_variable *sampler,

-		       ir_dereference *deref)

-{

-   ir_sampler_replacement_visitor v(sampler, deref);

-

-   visit_list_elements(&v, instructions);

-}

+/*
+ * Copyright © 2010 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.
+ */
+
+/**
+ * \file opt_function_inlining.cpp
+ *
+ * Replaces calls to functions with the body of the function.
+ */
+
+#include <inttypes.h>
+#include "ir.h"
+#include "ir_visitor.h"
+#include "ir_function_inlining.h"
+#include "ir_expression_flattening.h"
+#include "glsl_types.h"
+#include "program/hash_table.h"
+
+static void
+do_sampler_replacement(exec_list *instructions,
+		       ir_variable *sampler,
+		       ir_dereference *deref);
+
+class ir_function_inlining_visitor : public ir_hierarchical_visitor {
+public:
+   ir_function_inlining_visitor()
+   {
+      progress = false;
+   }
+
+   virtual ~ir_function_inlining_visitor()
+   {
+      /* empty */
+   }
+
+   virtual ir_visitor_status visit_enter(ir_expression *);
+   virtual ir_visitor_status visit_enter(ir_call *);
+   virtual ir_visitor_status visit_enter(ir_assignment *);
+   virtual ir_visitor_status visit_enter(ir_return *);
+   virtual ir_visitor_status visit_enter(ir_texture *);
+   virtual ir_visitor_status visit_enter(ir_swizzle *);
+
+   bool progress;
+};
+
+
+bool
+automatic_inlining_predicate(ir_instruction *ir)
+{
+   ir_call *call = ir->as_call();
+
+   if (call && can_inline(call))
+      return true;
+
+   return false;
+}
+
+bool
+do_function_inlining(exec_list *instructions)
+{
+   ir_function_inlining_visitor v;
+
+   do_expression_flattening(instructions, automatic_inlining_predicate);
+
+   v.run(instructions);
+
+   return v.progress;
+}
+
+static void
+replace_return_with_assignment(ir_instruction *ir, void *data)
+{
+   void *ctx = ralloc_parent(ir);
+   ir_variable *retval = (ir_variable *)data;
+   ir_return *ret = ir->as_return();
+
+   if (ret) {
+      if (ret->value) {
+	 ir_rvalue *lhs = new(ctx) ir_dereference_variable(retval);
+	 ret->replace_with(new(ctx) ir_assignment(lhs, ret->value, NULL));
+      } else {
+	 /* un-valued return has to be the last return, or we shouldn't
+	  * have reached here. (see can_inline()).
+	  */
+	 assert(ret->next->is_tail_sentinel());
+	 ret->remove();
+      }
+   }
+}
+
+ir_rvalue *
+ir_call::generate_inline(ir_instruction *next_ir)
+{
+   void *ctx = ralloc_parent(this);
+   ir_variable **parameters;
+   int num_parameters;
+   int i;
+   ir_variable *retval = NULL;
+   struct hash_table *ht;
+
+   ht = hash_table_ctor(0, hash_table_pointer_hash, hash_table_pointer_compare);
+
+   num_parameters = 0;
+   foreach_iter(exec_list_iterator, iter_sig, this->callee->parameters)
+      num_parameters++;
+
+   parameters = new ir_variable *[num_parameters];
+
+   /* Generate storage for the return value. */
+   if (this->callee->return_type) {
+      retval = new(ctx) ir_variable(this->callee->return_type, "_ret_val",
+				    ir_var_auto);
+      next_ir->insert_before(retval);
+   }
+
+   /* Generate the declarations for the parameters to our inlined code,
+    * and set up the mapping of real function body variables to ours.
+    */
+   i = 0;
+   exec_list_iterator sig_param_iter = this->callee->parameters.iterator();
+   exec_list_iterator param_iter = this->actual_parameters.iterator();
+   for (i = 0; i < num_parameters; i++) {
+      ir_variable *sig_param = (ir_variable *) sig_param_iter.get();
+      ir_rvalue *param = (ir_rvalue *) param_iter.get();
+
+      /* Generate a new variable for the parameter. */
+      if (sig_param->type->base_type == GLSL_TYPE_SAMPLER) {
+	 /* For samplers, we want the inlined sampler references
+	  * referencing the passed in sampler variable, since that
+	  * will have the location information, which an assignment of
+	  * a sampler wouldn't.  Fix it up below.
+	  */
+	 parameters[i] = NULL;
+      } else {
+	 parameters[i] = sig_param->clone(ctx, ht);
+	 parameters[i]->mode = ir_var_auto;
+
+	 /* Remove the read-only decoration becuase we're going to write
+	  * directly to this variable.  If the cloned variable is left
+	  * read-only and the inlined function is inside a loop, the loop
+	  * analysis code will get confused.
+	  */
+	 parameters[i]->read_only = false;
+	 next_ir->insert_before(parameters[i]);
+      }
+
+      /* Move the actual param into our param variable if it's an 'in' type. */
+      if (parameters[i] && (sig_param->mode == ir_var_in ||
+			    sig_param->mode == ir_var_const_in ||
+			    sig_param->mode == ir_var_inout)) {
+	 ir_assignment *assign;
+
+	 assign = new(ctx) ir_assignment(new(ctx) ir_dereference_variable(parameters[i]),
+					 param, NULL);
+	 next_ir->insert_before(assign);
+      }
+
+      sig_param_iter.next();
+      param_iter.next();
+   }
+
+   exec_list new_instructions;
+
+   /* Generate the inlined body of the function to a new list */
+   foreach_iter(exec_list_iterator, iter, callee->body) {
+      ir_instruction *ir = (ir_instruction *)iter.get();
+      ir_instruction *new_ir = ir->clone(ctx, ht);
+
+      new_instructions.push_tail(new_ir);
+      visit_tree(new_ir, replace_return_with_assignment, retval);
+   }
+
+   /* If any samplers were passed in, replace any deref of the sampler
+    * with a deref of the sampler argument.
+    */
+   param_iter = this->actual_parameters.iterator();
+   sig_param_iter = this->callee->parameters.iterator();
+   for (i = 0; i < num_parameters; i++) {
+      ir_instruction *const param = (ir_instruction *) param_iter.get();
+      ir_variable *sig_param = (ir_variable *) sig_param_iter.get();
+
+      if (sig_param->type->base_type == GLSL_TYPE_SAMPLER) {
+	 ir_dereference *deref = param->as_dereference();
+
+	 assert(deref);
+	 do_sampler_replacement(&new_instructions, sig_param, deref);
+      }
+      param_iter.next();
+      sig_param_iter.next();
+   }
+
+   /* Now push those new instructions in. */
+   foreach_iter(exec_list_iterator, iter, new_instructions) {
+      ir_instruction *ir = (ir_instruction *)iter.get();
+      next_ir->insert_before(ir);
+   }
+
+   /* Copy back the value of any 'out' parameters from the function body
+    * variables to our own.
+    */
+   i = 0;
+   param_iter = this->actual_parameters.iterator();
+   sig_param_iter = this->callee->parameters.iterator();
+   for (i = 0; i < num_parameters; i++) {
+      ir_instruction *const param = (ir_instruction *) param_iter.get();
+      const ir_variable *const sig_param = (ir_variable *) sig_param_iter.get();
+
+      /* Move our param variable into the actual param if it's an 'out' type. */
+      if (parameters[i] && (sig_param->mode == ir_var_out ||
+			    sig_param->mode == ir_var_inout)) {
+	 ir_assignment *assign;
+
+	 assign = new(ctx) ir_assignment(param->clone(ctx, NULL)->as_rvalue(),
+					 new(ctx) ir_dereference_variable(parameters[i]),
+					 NULL);
+	 next_ir->insert_before(assign);
+      }
+
+      param_iter.next();
+      sig_param_iter.next();
+   }
+
+   delete [] parameters;
+
+   hash_table_dtor(ht);
+
+   if (retval)
+      return new(ctx) ir_dereference_variable(retval);
+   else
+      return NULL;
+}
+
+
+ir_visitor_status
+ir_function_inlining_visitor::visit_enter(ir_expression *ir)
+{
+   (void) ir;
+   return visit_continue_with_parent;
+}
+
+
+ir_visitor_status
+ir_function_inlining_visitor::visit_enter(ir_return *ir)
+{
+   (void) ir;
+   return visit_continue_with_parent;
+}
+
+
+ir_visitor_status
+ir_function_inlining_visitor::visit_enter(ir_texture *ir)
+{
+   (void) ir;
+   return visit_continue_with_parent;
+}
+
+
+ir_visitor_status
+ir_function_inlining_visitor::visit_enter(ir_swizzle *ir)
+{
+   (void) ir;
+   return visit_continue_with_parent;
+}
+
+
+ir_visitor_status
+ir_function_inlining_visitor::visit_enter(ir_call *ir)
+{
+   if (can_inline(ir)) {
+      /* If the call was part of some tree, then it should have been
+       * flattened out or we shouldn't have seen it because of a
+       * visit_continue_with_parent in this visitor.
+       */
+      assert(ir == base_ir);
+
+      (void) ir->generate_inline(ir);
+      ir->remove();
+      this->progress = true;
+   }
+
+   return visit_continue;
+}
+
+
+ir_visitor_status
+ir_function_inlining_visitor::visit_enter(ir_assignment *ir)
+{
+   ir_call *call = ir->rhs->as_call();
+   if (!call || !can_inline(call))
+      return visit_continue;
+
+   /* generates the parameter setup, function body, and returns the return
+    * value of the function
+    */
+   ir_rvalue *rhs = call->generate_inline(ir);
+   assert(rhs);
+
+   ir->rhs = rhs;
+   this->progress = true;
+
+   return visit_continue;
+}
+
+/**
+ * Replaces references to the "sampler" variable with a clone of "deref."
+ *
+ * From the spec, samplers can appear in the tree as function
+ * (non-out) parameters and as the result of array indexing and
+ * structure field selection.  In our builtin implementation, they
+ * also appear in the sampler field of an ir_tex instruction.
+ */
+
+class ir_sampler_replacement_visitor : public ir_hierarchical_visitor {
+public:
+   ir_sampler_replacement_visitor(ir_variable *sampler, ir_dereference *deref)
+   {
+      this->sampler = sampler;
+      this->deref = deref;
+   }
+
+   virtual ~ir_sampler_replacement_visitor()
+   {
+   }
+
+   virtual ir_visitor_status visit_leave(ir_call *);
+   virtual ir_visitor_status visit_leave(ir_dereference_array *);
+   virtual ir_visitor_status visit_leave(ir_dereference_record *);
+   virtual ir_visitor_status visit_leave(ir_texture *);
+
+   void replace_deref(ir_dereference **deref);
+   void replace_rvalue(ir_rvalue **rvalue);
+
+   ir_variable *sampler;
+   ir_dereference *deref;
+};
+
+void
+ir_sampler_replacement_visitor::replace_deref(ir_dereference **deref)
+{
+   ir_dereference_variable *deref_var = (*deref)->as_dereference_variable();
+   if (deref_var && deref_var->var == this->sampler) {
+      *deref = this->deref->clone(ralloc_parent(*deref), NULL);
+   }
+}
+
+void
+ir_sampler_replacement_visitor::replace_rvalue(ir_rvalue **rvalue)
+{
+   if (!*rvalue)
+      return;
+
+   ir_dereference *deref = (*rvalue)->as_dereference();
+
+   if (!deref)
+      return;
+
+   replace_deref(&deref);
+   *rvalue = deref;
+}
+
+ir_visitor_status
+ir_sampler_replacement_visitor::visit_leave(ir_texture *ir)
+{
+   replace_deref(&ir->sampler);
+
+   return visit_continue;
+}
+
+ir_visitor_status
+ir_sampler_replacement_visitor::visit_leave(ir_dereference_array *ir)
+{
+   replace_rvalue(&ir->array);
+   return visit_continue;
+}
+
+ir_visitor_status
+ir_sampler_replacement_visitor::visit_leave(ir_dereference_record *ir)
+{
+   replace_rvalue(&ir->record);
+   return visit_continue;
+}
+
+ir_visitor_status
+ir_sampler_replacement_visitor::visit_leave(ir_call *ir)
+{
+   foreach_iter(exec_list_iterator, iter, *ir) {
+      ir_rvalue *param = (ir_rvalue *)iter.get();
+      ir_rvalue *new_param = param;
+      replace_rvalue(&new_param);
+
+      if (new_param != param) {
+	 param->replace_with(new_param);
+      }
+   }
+   return visit_continue;
+}
+
+static void
+do_sampler_replacement(exec_list *instructions,
+		       ir_variable *sampler,
+		       ir_dereference *deref)
+{
+   ir_sampler_replacement_visitor v(sampler, deref);
+
+   visit_list_elements(&v, instructions);
+}