glsl2: Add lowering pass to remove noise opcodes

1 files changed, 71 insertions, 0 deletions

diff --git a/src/glsl/lower_noise.cpp b/src/glsl/lower_noise.cpp
new file mode 100644
index 0000000000..cb32d28348
--- /dev/null
+++ b/src/glsl/lower_noise.cpp
@@ -0,0 +1,71 @@
+/*
+ * 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 lower_noise.cpp
+ * IR lower pass to remove noise opcodes.
+ *
+ * \author Ian Romanick <ian.d.romanick@intel.com>
+ */
+
+#include "ir.h"
+#include "ir_rvalue_visitor.h"
+
+class lower_noise_visitor : public ir_rvalue_visitor {
+public:
+   lower_noise_visitor() : progress(false)
+   {
+      /* empty */
+   }
+
+   void handle_rvalue(ir_rvalue **rvalue)
+   {
+      if (!*rvalue)
+	 return;
+
+      ir_expression *expr = (*rvalue)->as_expression();
+      if (!expr)
+	 return;
+
+      /* In the future, ir_unop_noise may be replaced by a call to a function
+       * that implements noise.  No hardware has a noise instruction.
+       */
+      if (expr->operation == ir_unop_noise) {
+	 *rvalue = ir_constant::zero(talloc_parent(expr), expr->type);
+	 this->progress = true;
+      }
+   }
+
+   bool progress;
+};
+
+
+bool
+lower_noise(exec_list *instructions)
+{
+   lower_noise_visitor v;
+
+   visit_list_elements(&v, instructions);
+
+   return v.progress;
+}