Add a constant folding optimization pass.

Makefile.am

@@ -28,7 +28,8 @@ glsl_SOURCES = symbol_table.c hash_table.c glsl_types.cpp \
 	ast_expr.cpp ast_to_hir.cpp ast_function.cpp ast_type.cpp \
 	ir.cpp hir_field_selection.cpp builtin_function.cpp \
 	ir_print_visitor.cpp ir_variable.cpp ir_function.cpp \
-	ir_constant_expression.cpp
+	ir_constant_expression.cpp \
+	ir_constant_folding.cpp
 
 BUILT_SOURCES = glsl_parser.h builtin_types.h glsl_parser.cpp glsl_lexer.cpp
 CLEANFILES = $(BUILT_SOURCES)

glsl_parser_extras.cpp

@@ -34,6 +34,7 @@
 #include "ast.h"
 #include "glsl_parser_extras.h"
 #include "glsl_parser.h"
+#include "ir_constant_folding.h"
 #include "ir_print_visitor.h"
 
 void
@@ -647,6 +648,16 @@ main(int argc, char **argv)
 
    _mesa_ast_to_hir(&instructions, &state);
 
+   /* Optimization passes */
+   if (!state.error) {
+      /* Constant folding */
+      foreach_iter(exec_list_iterator, iter, instructions) {
+	 ir_constant_folding_visitor v;
+	 ((ir_instruction *)iter.get())->accept(& v);
+      }
+   }
+
+   /* Print out the resulting IR */
    printf("\n\n");
 
    if (!state.error) {

ir_constant_folding.cpp

@@ -0,0 +1,131 @@
+/*
+ * 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.
+ */
+
+#define NULL 0
+#include "ir.h"
+#include "ir_visitor.h"
+#include "ir_constant_folding.h"
+#include "glsl_types.h"
+
+/**
+ * Visitor class for replacing expressions with ir_constant values.
+ */
+
+void
+ir_constant_folding_visitor::visit(ir_variable *ir)
+{
+   (void) ir;
+}
+
+
+void
+ir_constant_folding_visitor::visit(ir_label *ir)
+{
+   (void) ir;
+}
+
+
+void
+ir_constant_folding_visitor::visit(ir_function_signature *ir)
+{
+   (void) ir;
+}
+
+
+void
+ir_constant_folding_visitor::visit(ir_function *ir)
+{
+   (void) ir;
+}
+
+void
+ir_constant_folding_visitor::visit(ir_expression *ir)
+{
+   ir_constant *op[2];
+   unsigned int operand;
+
+   for (operand = 0; operand < ir->get_num_operands(); operand++) {
+      op[operand] = ir->operands[operand]->constant_expression_value();
+      if (op[operand]) {
+	 ir->operands[operand] = op[operand];
+      }
+   }
+}
+
+
+void
+ir_constant_folding_visitor::visit(ir_swizzle *ir)
+{
+   (void) ir;
+}
+
+
+void
+ir_constant_folding_visitor::visit(ir_dereference *ir)
+{
+   (void) ir;
+}
+
+
+void
+ir_constant_folding_visitor::visit(ir_assignment *ir)
+{
+   ir_constant *const_val = ir->rhs->constant_expression_value();
+   if (const_val)
+      ir->rhs = const_val;
+   else
+      ir->rhs->accept(this);
+}
+
+
+void
+ir_constant_folding_visitor::visit(ir_constant *ir)
+{
+   (void) ir;
+}
+
+
+void
+ir_constant_folding_visitor::visit(ir_call *ir)
+{
+   (void) ir;
+}
+
+
+void
+ir_constant_folding_visitor::visit(ir_return *ir)
+{
+   (void) ir;
+}
+
+
+void
+ir_constant_folding_visitor::visit(ir_if *ir)
+{
+   (void) ir;
+}

ir_constant_folding.h

@@ -0,0 +1,62 @@
+/*
+ * 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.h
+ * Replace constant-valued expressions with references to constant values.
+ */
+
+class ir_constant_folding_visitor : public ir_visitor {
+public:
+   ir_constant_folding_visitor()
+   {
+      /* empty */
+   }
+
+   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_label *);
+   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 *);
+   /*@}*/
+};