1 files changed, 80 insertions, 0 deletions
diff --git a/src/glsl/opt_noop_swizzle.cpp b/src/glsl/opt_noop_swizzle.cpp
new file mode 100644
index 00000000000..0a906aaf1da
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+++ b/src/glsl/opt_noop_swizzle.cpp
@@ -0,0 +1,80 @@
+/*
+ * 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_noop_swizzle.cpp
+ *
+ * If a swizzle doesn't change the order or count of components, then
+ * remove the swizzle so that other optimization passes see the value
+ * behind it.
+ */
+
+#include "ir.h"
+#include "ir_visitor.h"
+#include "ir_rvalue_visitor.h"
+#include "ir_print_visitor.h"
+#include "glsl_types.h"
+
+class ir_noop_swizzle_visitor : public ir_rvalue_visitor {
+public:
+   ir_noop_swizzle_visitor()
+   {
+      this->progress = false;
+   }
+
+   void handle_rvalue(ir_rvalue **rvalue);
+   bool progress;
+};
+
+void
+ir_noop_swizzle_visitor::handle_rvalue(ir_rvalue **rvalue)
+{
+   if (!*rvalue)
+      return;
+
+   ir_swizzle *swiz = (*rvalue)->as_swizzle();
+   if (!swiz || swiz->type != swiz->val->type)
+      return;
+
+   int elems = swiz->val->type->vector_elements;
+   if (swiz->mask.x != 0)
+      return;
+   if (elems >= 2 && swiz->mask.y != 1)
+      return;
+   if (elems >= 3 && swiz->mask.z != 2)
+      return;
+   if (elems >= 4 && swiz->mask.w != 3)
+      return;
+
+   this->progress = true;
+   *rvalue = swiz->val;
+}
+
+bool
+do_noop_swizzle(exec_list *instructions)
+{
+   ir_noop_swizzle_visitor v;
+   visit_list_elements(&v, instructions);
+
+   return v.progress;
+}