[Mesa-dev] [PATCH 09/12] glsl: Add a pass to propagate the "invariant" and "precise" qualifiers
Jason Ekstrand
jason at jlekstrand.net
Sat Mar 19 04:15:33 UTC 2016
On Fri, Mar 18, 2016 at 2:32 PM, Francisco Jerez <currojerez at riseup.net>
wrote:
> Jason Ekstrand <jason at jlekstrand.net> writes:
>
> > ---
> > src/compiler/Makefile.sources | 1 +
> > src/compiler/glsl/glsl_parser_extras.cpp | 1 +
> > src/compiler/glsl/ir_optimization.h | 1 +
> > src/compiler/glsl/propagate_invariance.cpp | 125
> +++++++++++++++++++++++++++++
> > 4 files changed, 128 insertions(+)
> > create mode 100644 src/compiler/glsl/propagate_invariance.cpp
> >
> > diff --git a/src/compiler/Makefile.sources
> b/src/compiler/Makefile.sources
> > index 9f3bcf0..6ab0aa7 100644
> > --- a/src/compiler/Makefile.sources
> > +++ b/src/compiler/Makefile.sources
> > @@ -129,6 +129,7 @@ LIBGLSL_FILES = \
> > glsl/opt_tree_grafting.cpp \
> > glsl/opt_vectorize.cpp \
> > glsl/program.h \
> > + glsl/propagate_invariance.cpp \
> > glsl/s_expression.cpp \
> > glsl/s_expression.h
> >
> > diff --git a/src/compiler/glsl/glsl_parser_extras.cpp
> b/src/compiler/glsl/glsl_parser_extras.cpp
> > index 1c6cd43..9fcca21 100644
> > --- a/src/compiler/glsl/glsl_parser_extras.cpp
> > +++ b/src/compiler/glsl/glsl_parser_extras.cpp
> > @@ -1885,6 +1885,7 @@ do_common_optimization(exec_list *ir, bool linked,
> > OPT(do_dead_functions, ir);
> > OPT(do_structure_splitting, ir);
> > }
> > + propagate_invariance(ir);
> > OPT(do_if_simplification, ir);
> > OPT(opt_flatten_nested_if_blocks, ir);
> > OPT(opt_conditional_discard, ir);
> > diff --git a/src/compiler/glsl/ir_optimization.h
> b/src/compiler/glsl/ir_optimization.h
> > index b56413a..4616f16 100644
> > --- a/src/compiler/glsl/ir_optimization.h
> > +++ b/src/compiler/glsl/ir_optimization.h
> > @@ -138,6 +138,7 @@ bool lower_tess_level(gl_shader *shader);
> > bool lower_vertex_id(gl_shader *shader);
> >
> > bool lower_subroutine(exec_list *instructions, struct
> _mesa_glsl_parse_state *state);
> > +void propagate_invariance(exec_list *instructions);
> >
> > ir_rvalue *
> > compare_index_block(exec_list *instructions, ir_variable *index,
> > diff --git a/src/compiler/glsl/propagate_invariance.cpp
> b/src/compiler/glsl/propagate_invariance.cpp
> > new file mode 100644
> > index 0000000..820259e
> > --- /dev/null
> > +++ b/src/compiler/glsl/propagate_invariance.cpp
> > @@ -0,0 +1,125 @@
> > +/*
> > + * Copyright © 2010 Intel Corporation
> > + *
>
> Wow, that's been a while ;)
>
Right. That's what I get for blindly copying and pasting. Updated to 2016
locally. Thanks!
> > + * 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 propagate_invariance.cpp
> > + * Propagate the "invariant" and "precise" qualifiers to variables used
> to
> > + * compute invariant or precise values.
> > + *
> > + * The GLSL spec (depending on what version you read) says, among the
> > + * conditions for geting bit-for-bit the same values on an invariant
> output:
> > + *
> > + * "All operations in the consuming expressions and any intermediate
> > + * expressions must be the same, with the same order of operands and
> same
> > + * associativity, to give the same order of evaluation."
> > + *
> > + * This effectively means that if a variable is used to compute an
> invariant
> > + * value then that variable becomes invariant. The same should apply
> to the
> > + * "precise" qualifier.
> > + */
> > +
> > +#include "ir.h"
> > +#include "ir_visitor.h"
> > +#include "ir_rvalue_visitor.h"
> > +#include "ir_optimization.h"
> > +#include "compiler/glsl_types.h"
> > +
> > +namespace {
> > +
> > +class ir_invariance_propagation_visitor : public
> ir_hierarchical_visitor {
> > +public:
> > + ir_invariance_propagation_visitor()
> > + {
> > + this->progress = false;
> > + this->dst_var = NULL;
> > + }
> > +
> > + virtual ~ir_invariance_propagation_visitor()
> > + {
> > + /* empty */
> > + }
> > +
>
> Redundant destructor?
>
Perhaps? I thought it was somewhat customary to always provide a virtual
destructor whenever you have any sort of "real" inheritance going on. I
guess it's probably ok since the one instantiation of this class is in this
file. However, the other passes I looked at all had destructors exactly
like that one so I just followed what they did.
I don't care one way or the other. I can remove it if you'd like.
--Jason
> > + virtual ir_visitor_status visit_enter(ir_assignment *ir);
> > + virtual ir_visitor_status visit_leave(ir_assignment *ir);
> > + virtual ir_visitor_status visit(ir_dereference_variable *ir);
> > +
> > + ir_variable *dst_var;
> > + bool progress;
> > +};
> > +
> > +} /* unnamed namespace */
> > +
> > +ir_visitor_status
> > +ir_invariance_propagation_visitor::visit_enter(ir_assignment *ir)
> > +{
> > + assert(this->dst_var == NULL);
> > + ir_variable *var = ir->lhs->variable_referenced();
> > + if (var->data.invariant || var->data.precise) {
> > + this->dst_var = var;
> > + return visit_continue;
> > + } else {
> > + return visit_continue_with_parent;
> > + }
> > +}
> > +
> > +ir_visitor_status
> > +ir_invariance_propagation_visitor::visit_leave(ir_assignment *ir)
> > +{
> > + this->dst_var = NULL;
> > +
> > + return visit_continue;
> > +}
> > +
> > +ir_visitor_status
> > +ir_invariance_propagation_visitor::visit(ir_dereference_variable *ir)
> > +{
> > + if (this->dst_var == NULL)
> > + return visit_continue;
> > +
> > + if (this->dst_var->data.invariant) {
> > + if (!ir->var->data.invariant)
> > + this->progress = true;
> > +
> > + ir->var->data.invariant = true;
> > + }
> > +
> > + if (this->dst_var->data.precise) {
> > + if (!ir->var->data.precise)
> > + this->progress = true;
> > +
> > + ir->var->data.precise = true;
> > + }
> > +
> > + return visit_continue;
> > +}
> > +
> > +void
> > +propagate_invariance(exec_list *instructions)
> > +{
> > + ir_invariance_propagation_visitor visitor;
> > +
> > + do {
> > + visitor.progress = false;
> > + visit_list_elements(&visitor, instructions);
> > + } while (visitor.progress);
> > +}
>
> Reviewed-by: Francisco Jerez <currojerez at riseup.net>
>
> > --
> > 2.5.0.400.gff86faf
> >
> > _______________________________________________
> > mesa-dev mailing list
> > mesa-dev at lists.freedesktop.org
> > https://lists.freedesktop.org/mailman/listinfo/mesa-dev
>
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