ir_copy_propagation: New pass to rewrite dereferences to avoid copies.

This is pretty basic.  Right now it only handles pure assignments --
same type on each side, no swizzling, and only within basic blocks.

1 files changed, 207 insertions, 0 deletions

diff --git a/ir_visit_tree.cpp b/ir_visit_tree.cpp
new file mode 100644
index 0000000000..89def6a920
--- /dev/null
+++ b/ir_visit_tree.cpp
@@ -0,0 +1,207 @@
+/*
+ * 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_dead_code.cpp
+ *
+ * Eliminates dead assignments and variable declarations from the code.
+ */
+
+#define NULL 0
+#include "ir.h"
+#include "ir_visitor.h"
+#include "ir_visit_tree.h"
+
+class ir_tree_visitor : public ir_visitor {
+public:
+
+   /**
+    * \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_loop *);
+   virtual void visit(ir_loop_jump *);
+   virtual void visit(ir_function_signature *);
+   virtual void visit(ir_function *);
+   virtual void visit(ir_expression *);
+   virtual void visit(ir_swizzle *);
+   virtual void visit(ir_dereference *);
+   virtual void visit(ir_assignment *);
+   virtual void visit(ir_constant *);
+   virtual void visit(ir_call *);
+   virtual void visit(ir_return *);
+   virtual void visit(ir_if *);
+   /*@}*/
+
+   void (*callback)(ir_instruction *ir, void *data);
+   void *data;
+};
+
+void
+ir_tree_visitor::visit(ir_variable *ir)
+{
+   this->callback(ir, this->data);
+}
+
+
+void
+ir_tree_visitor::visit(ir_loop *ir)
+{
+   this->callback(ir, this->data);
+
+   visit_exec_list(&ir->body_instructions, this);
+   if (ir->from)
+      ir->from->accept(this);
+   if (ir->to)
+      ir->to->accept(this);
+   if (ir->increment)
+      ir->increment->accept(this);
+}
+
+void
+ir_tree_visitor::visit(ir_loop_jump *ir)
+{
+   this->callback(ir, this->data);
+}
+
+
+void
+ir_tree_visitor::visit(ir_function_signature *ir)
+{
+   this->callback(ir, this->data);
+
+   visit_exec_list(&ir->body, this);
+}
+
+void
+ir_tree_visitor::visit(ir_function *ir)
+{
+   this->callback(ir, this->data);
+
+   /* FINISHME: Do we want to walk into functions? */
+}
+
+void
+ir_tree_visitor::visit(ir_expression *ir)
+{
+   unsigned int operand;
+
+   this->callback(ir, this->data);
+
+   for (operand = 0; operand < ir->get_num_operands(); operand++) {
+      ir->operands[operand]->accept(this);
+   }
+}
+
+
+void
+ir_tree_visitor::visit(ir_swizzle *ir)
+{
+   this->callback(ir, this->data);
+
+   ir->val->accept(this);
+}
+
+
+void
+ir_tree_visitor::visit(ir_dereference *ir)
+{
+   this->callback(ir, this->data);
+
+   if (ir->mode == ir_dereference::ir_reference_array) {
+      ir->selector.array_index->accept(this);
+   }
+}
+
+void
+ir_tree_visitor::visit(ir_assignment *ir)
+{
+   this->callback(ir, this->data);
+
+   ir->lhs->accept(this);
+   ir->rhs->accept(this);
+   if (ir->condition)
+      ir->condition->accept(this);
+}
+
+
+void
+ir_tree_visitor::visit(ir_constant *ir)
+{
+   this->callback(ir, this->data);
+}
+
+
+void
+ir_tree_visitor::visit(ir_call *ir)
+{
+   this->callback(ir, this->data);
+
+   foreach_iter(exec_list_iterator, iter, *ir) {
+      ir_rvalue *param = (ir_rvalue *)iter.get();
+
+      param->accept(this);
+   }
+}
+
+
+void
+ir_tree_visitor::visit(ir_return *ir)
+{
+   ir_rvalue *val = ir->get_value();
+
+   this->callback(ir, this->data);
+
+   if (val)
+      val->accept(this);
+}
+
+
+void
+ir_tree_visitor::visit(ir_if *ir)
+{
+   this->callback(ir, this->data);
+
+   ir->condition->accept(this);
+
+   visit_exec_list(&ir->then_instructions, this);
+   visit_exec_list(&ir->else_instructions, this);
+}
+
+void ir_visit_tree(ir_instruction *ir,
+		   void (*callback)(ir_instruction *ir,
+				    void *data),
+		   void *data)
+{
+   ir_tree_visitor v;
+   v.callback = callback;
+   v.data = data;
+
+   ir->accept(&v);
+}
+