Jason Ekstrand <ja...@jlekstrand.net> writes: > diff --git a/src/compiler/nir/nir_opt_copy_prop_vars.c > b/src/compiler/nir/nir_opt_copy_prop_vars.c > new file mode 100644 > index 0000000..728e476 > --- /dev/null > +++ b/src/compiler/nir/nir_opt_copy_prop_vars.c > @@ -0,0 +1,799 @@ > +/* > + * Copyright © 2016 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. > + */ > + > +#include "nir.h" > +#include "nir_builder.h" > + > +/** > + * Variable-based copy propagation > + * > + * Normally, NIR trusts in SSA form for most of its copy-propagation needs. > + * However, there are cases, especially when dealing with indirects, where > SSA > + * won't help you. This pass is for those times. Specifically, it handles > + * the following things that the rest of NIR can't: > + * > + * 1) Copy-propagation on variables that have indirect access. This > includes > + * propagating from indirect stores into indirect loads. > + * > + * 2) Dead code elimination of store_var and copy_var intrinsics based on > + * killed destination values. > + * > + * 3) Removal of redundant load_var intrinsics. We can't trust regular CSE > + * to do this because it isn't aware of variable writes that may alias > the > + * value and make the former load invalid. > + * > + * Unfortunately, properly handling all of those cases makes this path rather > + * complex. In order to avoid additional complexity, this pass is entirely > + * block-local. If we tried to make it local the data-flow analysis would
I think here you wanted to say "make it global." I haven't reviewed the rest, I was just skimming to see what you were up to. > + * rapidly get out of hand. Fortunately, for anything that is only ever > + * accessed directly, we get SSA based copy-propagation which is extremely > + * powerful so this isn't that great a loss. > + */
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