1 files changed, 93 insertions, 0 deletions
diff --git a/src/compiler/nir/nir_opt_cse.c b/src/compiler/nir/nir_opt_cse.c
new file mode 100644
index 00000000000..364fb023dce
--- /dev/null
+++ b/src/compiler/nir/nir_opt_cse.c
@@ -0,0 +1,93 @@
+/*
+ * Copyright © 2014 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.
+ *
+ * Authors:
+ *    Jason Ekstrand (jason@jlekstrand.net)
+ *    Connor Abbott (cwabbott0@gmail.com)
+ *
+ */
+
+#include "nir_instr_set.h"
+
+/*
+ * Implements common subexpression elimination
+ */
+
+/*
+ * Visits and CSE's the given block and all its descendants in the dominance
+ * tree recursively. Note that the instr_set is guaranteed to only ever
+ * contain instructions that dominate the current block.
+ */
+
+static bool
+cse_block(nir_block *block, struct set *instr_set)
+{
+   bool progress = false;
+
+   nir_foreach_instr_safe(block, instr) {
+      if (nir_instr_set_add_or_rewrite(instr_set, instr)) {
+         progress = true;
+         nir_instr_remove(instr);
+      }
+   }
+
+   for (unsigned i = 0; i < block->num_dom_children; i++) {
+      nir_block *child = block->dom_children[i];
+      progress |= cse_block(child, instr_set);
+   }
+
+   nir_foreach_instr(block, instr)
+     nir_instr_set_remove(instr_set, instr);
+
+   return progress;
+}
+
+static bool
+nir_opt_cse_impl(nir_function_impl *impl)
+{
+   struct set *instr_set = nir_instr_set_create(NULL);
+
+   nir_metadata_require(impl, nir_metadata_dominance);
+
+   bool progress = cse_block(nir_start_block(impl), instr_set);
+
+   if (progress)
+      nir_metadata_preserve(impl, nir_metadata_block_index |
+                                  nir_metadata_dominance);
+
+   nir_instr_set_destroy(instr_set);
+   return progress;
+}
+
+bool
+nir_opt_cse(nir_shader *shader)
+{
+   bool progress = false;
+
+   nir_foreach_function(shader, function) {
+      if (function->impl)
+         progress |= nir_opt_cse_impl(function->impl);
+   }
+
+   return progress;
+}
+