[Mesa-dev] [PATCH 3/4] glsl: Merge if-simplification and conditional discard optimization
Thomas Helland
thomashelland90 at gmail.com
Tue May 16 12:35:36 UTC 2017
2017-05-16 3:31 GMT+02:00 Matt Turner <mattst88 at gmail.com>:
> On Mon, Apr 24, 2017 at 4:50 PM, Matt Turner <mattst88 at gmail.com> wrote:
>> On Thu, Apr 6, 2017 at 12:49 PM, Thomas Helland
>> <thomashelland90 at gmail.com> wrote:
>>> The conditional discard pass follows the same pattern, so merge the
>>> two, and avoid running the visitor two times.
>>> ---
>>> src/compiler/Makefile.sources | 1 -
>>> src/compiler/glsl/glsl_parser_extras.cpp | 1 -
>>> src/compiler/glsl/ir_optimization.h | 1 -
>>> src/compiler/glsl/opt_conditional_discard.cpp | 88 ---------------------------
>>> src/compiler/glsl/opt_if_simplification.cpp | 50 +++++++++++----
>>> 5 files changed, 39 insertions(+), 102 deletions(-)
>>> delete mode 100644 src/compiler/glsl/opt_conditional_discard.cpp
>>>
>>> diff --git a/src/compiler/Makefile.sources b/src/compiler/Makefile.sources
>>> index 5197c31bb3..817ab3a755 100644
>>> --- a/src/compiler/Makefile.sources
>>> +++ b/src/compiler/Makefile.sources
>>> @@ -114,7 +114,6 @@ LIBGLSL_FILES = \
>>> glsl/lower_ubo_reference.cpp \
>>> glsl/opt_algebraic.cpp \
>>> glsl/opt_array_splitting.cpp \
>>> - glsl/opt_conditional_discard.cpp \
>>> glsl/opt_constant_folding.cpp \
>>> glsl/opt_constant_propagation.cpp \
>>> glsl/opt_constant_variable.cpp \
>>> diff --git a/src/compiler/glsl/glsl_parser_extras.cpp b/src/compiler/glsl/glsl_parser_extras.cpp
>>> index 307e0d6215..fe25c23ccc 100644
>>> --- a/src/compiler/glsl/glsl_parser_extras.cpp
>>> +++ b/src/compiler/glsl/glsl_parser_extras.cpp
>>> @@ -2139,7 +2139,6 @@ do_common_optimization(exec_list *ir, bool linked,
>>> }
>>> propagate_invariance(ir);
>>> OPT(do_if_simplification, ir);
>>> - OPT(opt_conditional_discard, ir);
>>> OPT(do_copy_propagation, ir);
>>> OPT(do_copy_propagation_elements, ir);
>>>
>>> diff --git a/src/compiler/glsl/ir_optimization.h b/src/compiler/glsl/ir_optimization.h
>>> index 5d57ca85fd..022b7ab12f 100644
>>> --- a/src/compiler/glsl/ir_optimization.h
>>> +++ b/src/compiler/glsl/ir_optimization.h
>>> @@ -93,7 +93,6 @@ bool ir_constant_fold(ir_rvalue **rvalue);
>>> bool do_rebalance_tree(exec_list *instructions);
>>> bool do_algebraic(exec_list *instructions, bool native_integers,
>>> const struct gl_shader_compiler_options *options);
>>> -bool opt_conditional_discard(exec_list *instructions);
>>> bool do_constant_folding(exec_list *instructions);
>>> bool do_constant_variable(exec_list *instructions);
>>> bool do_constant_variable_unlinked(exec_list *instructions);
>>> diff --git a/src/compiler/glsl/opt_conditional_discard.cpp b/src/compiler/glsl/opt_conditional_discard.cpp
>>> deleted file mode 100644
>>> index 6d8a23460d..0000000000
>>> --- a/src/compiler/glsl/opt_conditional_discard.cpp
>>> +++ /dev/null
>>> @@ -1,88 +0,0 @@
>>> -/*
>>> - * 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.
>>> - */
>>> -
>>> -/**
>>> - * \file opt_conditional_discard.cpp
>>> - *
>>> - * Replace
>>> - *
>>> - * if (cond) discard;
>>> - *
>>> - * with
>>> - *
>>> - * (discard <condition>)
>>> - */
>>> -
>>> -#include "compiler/glsl_types.h"
>>> -#include "ir.h"
>>> -
>>> -namespace {
>>> -
>>> -class opt_conditional_discard_visitor : public ir_hierarchical_visitor {
>>> -public:
>>> - opt_conditional_discard_visitor()
>>> - {
>>> - progress = false;
>>> - }
>>> -
>>> - ir_visitor_status visit_leave(ir_if *);
>>> -
>>> - bool progress;
>>> -};
>>> -
>>> -} /* anonymous namespace */
>>> -
>>> -bool
>>> -opt_conditional_discard(exec_list *instructions)
>>> -{
>>> - opt_conditional_discard_visitor v;
>>> - v.run(instructions);
>>> - return v.progress;
>>> -}
>>> -
>>> -ir_visitor_status
>>> -opt_conditional_discard_visitor::visit_leave(ir_if *ir)
>>> -{
>>> - /* Look for "if (...) discard" with no else clause or extra statements. */
>>> - if (ir->then_instructions.is_empty() ||
>>> - !ir->then_instructions.get_head_raw()->next->is_tail_sentinel() ||
>>> - !((ir_instruction *) ir->then_instructions.get_head_raw())->as_discard() ||
>>> - !ir->else_instructions.is_empty())
>>> - return visit_continue;
>>> -
>>> - /* Move the condition and replace the ir_if with the ir_discard. */
>>> - ir_discard *discard = (ir_discard *) ir->then_instructions.get_head_raw();
>>> - if (!discard->condition)
>>> - discard->condition = ir->condition;
>>> - else {
>>> - void *ctx = ralloc_parent(ir);
>>> - discard->condition = new(ctx) ir_expression(ir_binop_logic_and,
>>> - ir->condition,
>>> - discard->condition);
>>> - }
>>> - ir->replace_with(discard);
>>> -
>>> - progress = true;
>>> -
>>> - return visit_continue;
>>> -}
>>> diff --git a/src/compiler/glsl/opt_if_simplification.cpp b/src/compiler/glsl/opt_if_simplification.cpp
>>> index 05159319ba..64c56d0a2f 100644
>>> --- a/src/compiler/glsl/opt_if_simplification.cpp
>>> +++ b/src/compiler/glsl/opt_if_simplification.cpp
>>> @@ -44,23 +44,12 @@ public:
>>> }
>>>
>>> ir_visitor_status visit_leave(ir_if *);
>>> - ir_visitor_status visit_enter(ir_assignment *);
>>>
>>> bool made_progress;
>>> };
>>>
>>> } /* unnamed namespace */
>>>
>>> -/* We only care about the top level "if" instructions, so don't
>>> - * descend into expressions.
>>> - */
>>> -ir_visitor_status
>>> -ir_if_simplification_visitor::visit_enter(ir_assignment *ir)
>>> -{
>>> - (void) ir;
>>> - return visit_continue_with_parent;
>>> -}
>>
>> I don't understand this change. What's going on?
>>
>> (Everything else in the series looks good. I've made a few trivial
>> changes locally -- whitespace mostly)
>
> As far as I'm aware, the series is blocked waiting on this.
Oh, wow! I'm really sorry for that one. I really need to get my
email filter working again, cause I keep missing these mails :/
Quite frankly, I don't understand this change either.
Looking back at it now, the only idea that pops to mind is that
opt_conditional_discard did not have this hook in it.
So the two passes do not follow the exact same pattern,
so to not introduce a functional change I removed it.
I don't see a good reason for this change though, so I'm
currently running some tests with this part in,
just to be on the safe side. I'll keep you posted.
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