ir_swizzle_swizzle: Reduce swizzle chains to a single swizzle.

Makefile.am

@@ -48,7 +48,11 @@ glsl_SOURCES = \
 	ir_hv_accept.cpp \
 	ir_hierarchical_visitor.h \
 	ir_hierarchical_visitor.cpp \
+	ir_swizzle_swizzle.cpp \
 	ir_vec_index_to_swizzle.cpp
+	ir_vec_index_to_swizzle.cpp \
+	ir_visit_tree.cpp \
+	ir_visit_tree.h
 
 BUILT_SOURCES = glsl_parser.h glsl_parser.cpp glsl_lexer.cpp
 CLEANFILES = $(BUILT_SOURCES)

glsl_parser_extras.cpp

@@ -760,6 +760,7 @@ main(int argc, char **argv)
 	 progress = do_dead_code_unlinked(&instructions) || progress;
 	 progress = do_constant_folding(&instructions) || progress;
 	 progress = do_vec_index_to_swizzle(&instructions) || progress;
+	 progress = do_swizzle_swizzle(&instructions) || progress;
       } while (progress);
    }
 

ir_optimization.h

@@ -35,4 +35,5 @@ bool do_dead_code_local(exec_list *instructions);
 bool do_dead_code_unlinked(exec_list *instructions);
 bool do_function_inlining(exec_list *instructions);
 bool do_if_simplification(exec_list *instructions);
+bool do_swizzle_swizzle(exec_list *instructions);
 bool do_vec_index_to_swizzle(exec_list *instructions);

ir_swizzle_swizzle.cpp

@@ -0,0 +1,94 @@
+/*
+ * 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_swizzle_swizzle.cpp
+ *
+ * Eliminates the second swizzle in a swizzle chain.
+ */
+
+#include <stdio.h>
+#include "ir.h"
+#include "ir_visitor.h"
+#include "ir_optimization.h"
+#include "glsl_types.h"
+
+class ir_swizzle_swizzle_visitor : public ir_hierarchical_visitor {
+public:
+   ir_swizzle_swizzle_visitor()
+   {
+      progress = false;
+   }
+
+   virtual ir_visitor_status visit_enter(ir_swizzle *);
+
+   bool progress;
+};
+
+ir_visitor_status
+ir_swizzle_swizzle_visitor::visit_enter(ir_swizzle *ir)
+{
+   int mask2[4];
+
+   ir_swizzle *swiz2 = ir->val->as_swizzle();
+   if (!swiz2)
+      return visit_continue;
+
+   memset(&mask2, 0, sizeof(mask2));
+   if (swiz2->mask.num_components >= 1)
+      mask2[0] = swiz2->mask.x;
+   if (swiz2->mask.num_components >= 2)
+      mask2[1] = swiz2->mask.y;
+   if (swiz2->mask.num_components >= 3)
+      mask2[2] = swiz2->mask.z;
+   if (swiz2->mask.num_components >= 4)
+      mask2[3] = swiz2->mask.w;
+
+   if (ir->mask.num_components >= 1)
+      ir->mask.x = mask2[ir->mask.x];
+   if (ir->mask.num_components >= 2)
+      ir->mask.y = mask2[ir->mask.y];
+   if (ir->mask.num_components >= 3)
+      ir->mask.z = mask2[ir->mask.z];
+   if (ir->mask.num_components >= 4)
+      ir->mask.w = mask2[ir->mask.w];
+
+   ir->val = swiz2->val;
+
+   this->progress = true;
+
+   return visit_continue;
+}
+
+/**
+ * Does a copy propagation pass on the code present in the instruction stream.
+ */
+bool
+do_swizzle_swizzle(exec_list *instructions)
+{
+   ir_swizzle_swizzle_visitor v;
+
+   v.run(instructions);
+
+   return v.progress;
+}