glsl: Combine nop-swizzle optimization with swizzle-swizzle optimization

Signed-off-by: Ian Romanick <ian.d.romanick@intel.com>
Reviewed-by: <thomashelland90@gmail.com>

src/compiler/glsl/opt_swizzle.cpp

@@ -0,0 +1,119 @@
+/*
+ * 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_swizzle.cpp
+ * Optimize swizzle operations.
+ *
+ * First, compact a sequence of swizzled swizzles into a single swizzle.
+ *
+ * If the final resulting 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 "compiler/glsl_types.h"
+
+namespace {
+
+class ir_opt_swizzle_visitor : public ir_rvalue_visitor {
+public:
+   ir_opt_swizzle_visitor()
+   {
+      this->progress = false;
+   }
+
+   void handle_rvalue(ir_rvalue **rvalue);
+   bool progress;
+};
+
+} /* unnamed namespace */
+
+void
+ir_opt_swizzle_visitor::handle_rvalue(ir_rvalue **rvalue)
+{
+   if (!*rvalue)
+      return;
+
+   ir_swizzle *swiz = (*rvalue)->as_swizzle();
+
+   if (!swiz)
+      return;
+
+   ir_swizzle *swiz2;
+
+   while ((swiz2 = swiz->val->as_swizzle()) != NULL) {
+      int mask2[4];
+
+      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 (swiz->mask.num_components >= 1)
+         swiz->mask.x = mask2[swiz->mask.x];
+      if (swiz->mask.num_components >= 2)
+         swiz->mask.y = mask2[swiz->mask.y];
+      if (swiz->mask.num_components >= 3)
+         swiz->mask.z = mask2[swiz->mask.z];
+      if (swiz->mask.num_components >= 4)
+         swiz->mask.w = mask2[swiz->mask.w];
+
+      swiz->val = swiz2->val;
+
+      this->progress = true;
+   }
+
+   if (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
+optimize_swizzles(exec_list *instructions)
+{
+   ir_opt_swizzle_visitor v;
+   visit_list_elements(&v, instructions);
+
+   return v.progress;
+}