1 files changed, 273 insertions, 0 deletions
diff --git a/src/glsl/ir_constant_folding.cpp b/src/glsl/ir_constant_folding.cpp
new file mode 100644
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+++ b/src/glsl/ir_constant_folding.cpp
@@ -0,0 +1,273 @@
+/*
+ * 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 ir_constant_folding.cpp
+ * Replace constant-valued expressions with references to constant values.
+ */
+
+#include "ir.h"
+#include "ir_visitor.h"
+#include "ir_optimization.h"
+#include "glsl_types.h"
+
+/**
+ * Visitor class for replacing expressions with ir_constant values.
+ */
+
+class ir_constant_folding_visitor : public ir_visitor {
+public:
+   ir_constant_folding_visitor()
+   {
+      this->progress = false;
+   }
+
+   virtual ~ir_constant_folding_visitor()
+   {
+      /* empty */
+   }
+
+   /**
+    * \name Visit methods
+    *
+    * As typical for the visitor pattern, there must be one \c visit method for
+    * each concrete subclass of \c ir_instruction.  Virtual base classes within
+    * the hierarchy should not have \c visit methods.
+    */
+   /*@{*/
+   virtual void visit(ir_variable *);
+   virtual void visit(ir_function_signature *);
+   virtual void visit(ir_function *);
+   virtual void visit(ir_expression *);
+   virtual void visit(ir_texture *);
+   virtual void visit(ir_swizzle *);
+   virtual void visit(ir_dereference_variable *);
+   virtual void visit(ir_dereference_array *);
+   virtual void visit(ir_dereference_record *);
+   virtual void visit(ir_assignment *);
+   virtual void visit(ir_constant *);
+   virtual void visit(ir_call *);
+   virtual void visit(ir_return *);
+   virtual void visit(ir_discard *);
+   virtual void visit(ir_if *);
+   virtual void visit(ir_loop *);
+   virtual void visit(ir_loop_jump *);
+   /*@}*/
+
+   void fold_constant(ir_rvalue **rvalue);
+
+   bool progress;
+};
+
+void
+ir_constant_folding_visitor::fold_constant(ir_rvalue **rvalue)
+{
+   if (*rvalue == NULL || (*rvalue)->ir_type == ir_type_constant)
+      return;
+
+   ir_constant *constant = (*rvalue)->constant_expression_value();
+   if (constant) {
+      *rvalue = constant;
+      this->progress = true;
+   } else {
+      (*rvalue)->accept(this);
+   }
+}
+
+void
+ir_constant_folding_visitor::visit(ir_variable *ir)
+{
+   (void) ir;
+}
+
+
+void
+ir_constant_folding_visitor::visit(ir_function_signature *ir)
+{
+   visit_exec_list(&ir->body, this);
+}
+
+
+void
+ir_constant_folding_visitor::visit(ir_function *ir)
+{
+   foreach_iter(exec_list_iterator, iter, *ir) {
+      ir_function_signature *const sig = (ir_function_signature *) iter.get();
+      sig->accept(this);
+   }
+}
+
+void
+ir_constant_folding_visitor::visit(ir_expression *ir)
+{
+   unsigned int operand;
+
+   for (operand = 0; operand < ir->get_num_operands(); operand++) {
+      fold_constant(&ir->operands[operand]);
+   }
+}
+
+
+void
+ir_constant_folding_visitor::visit(ir_texture *ir)
+{
+   fold_constant(&ir->coordinate);
+   fold_constant(&ir->projector);
+   fold_constant(&ir->shadow_comparitor);
+
+   switch (ir->op) {
+   case ir_tex:
+      break;
+   case ir_txb:
+      fold_constant(&ir->lod_info.bias);
+      break;
+   case ir_txf:
+   case ir_txl:
+      fold_constant(&ir->lod_info.lod);
+      break;
+   case ir_txd:
+      fold_constant(&ir->lod_info.grad.dPdx);
+      fold_constant(&ir->lod_info.grad.dPdy);
+      break;
+   }
+}
+
+
+void
+ir_constant_folding_visitor::visit(ir_swizzle *ir)
+{
+   fold_constant(&ir->val);
+}
+
+
+void
+ir_constant_folding_visitor::visit(ir_dereference_variable *ir)
+{
+   (void) ir;
+}
+
+
+void
+ir_constant_folding_visitor::visit(ir_dereference_array *ir)
+{
+   fold_constant(&ir->array_index);
+   ir->array->accept(this);
+}
+
+
+void
+ir_constant_folding_visitor::visit(ir_dereference_record *ir)
+{
+   ir->record->accept(this);
+}
+
+
+void
+ir_constant_folding_visitor::visit(ir_assignment *ir)
+{
+   fold_constant(&ir->rhs);
+
+   if (ir->condition) {
+      /* If the condition is constant, either remove the condition or
+       * remove the never-executed assignment.
+       */
+      ir_constant *const_val = ir->condition->constant_expression_value();
+      if (const_val) {
+	 if (const_val->value.b[0])
+	    ir->condition = NULL;
+	 else
+	    ir->remove();
+	 this->progress = true;
+      }
+   }
+}
+
+
+void
+ir_constant_folding_visitor::visit(ir_constant *ir)
+{
+   (void) ir;
+}
+
+
+void
+ir_constant_folding_visitor::visit(ir_call *ir)
+{
+   foreach_iter(exec_list_iterator, iter, *ir) {
+      ir_rvalue *param = (ir_rvalue *)iter.get();
+      ir_rvalue *new_param = param;
+      fold_constant(&new_param);
+
+      if (new_param != param) {
+	 param->replace_with(new_param);
+      }
+   }
+}
+
+
+void
+ir_constant_folding_visitor::visit(ir_return *ir)
+{
+   fold_constant(&ir->value);
+}
+
+
+void
+ir_constant_folding_visitor::visit(ir_discard *ir)
+{
+   (void) ir;
+}
+
+
+void
+ir_constant_folding_visitor::visit(ir_if *ir)
+{
+   fold_constant(&ir->condition);
+
+   visit_exec_list(&ir->then_instructions, this);
+   visit_exec_list(&ir->else_instructions, this);
+}
+
+
+void
+ir_constant_folding_visitor::visit(ir_loop *ir)
+{
+   (void) ir;
+}
+
+
+void
+ir_constant_folding_visitor::visit(ir_loop_jump *ir)
+{
+   (void) ir;
+}
+
+bool
+do_constant_folding(exec_list *instructions)
+{
+   ir_constant_folding_visitor constant_folding;
+
+   visit_exec_list(instructions, &constant_folding);
+
+   return constant_folding.progress;
+}