glsl: move to compiler/
Signed-off-by: Emil Velikov <emil.velikov@collabora.com> Acked-by: Matt Turner <mattst88@gmail.com> Acked-by: Jose Fonseca <jfonseca@vmware.com>
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committed by
Emil Velikov

parent
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commit
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488
src/compiler/glsl/opt_minmax.cpp
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488
src/compiler/glsl/opt_minmax.cpp
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/*
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* Copyright © 2014 Intel Corporation
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*
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* Permission is hereby granted, free of charge, to any person obtaining a
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* copy of this software and associated documentation files (the "Software"),
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* to deal in the Software without restriction, including without limitation
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* the rights to use, copy, modify, merge, publish, distribute, sublicense,
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* and/or sell copies of the Software, and to permit persons to whom the
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* Software is furnished to do so, subject to the following conditions:
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*
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* The above copyright notice and this permission notice (including the next
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* paragraph) shall be included in all copies or substantial portions of the
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* Software.
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
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* THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
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* FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
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* DEALINGS IN THE SOFTWARE.
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*/
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/**
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* \file opt_minmax.cpp
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*
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* Drop operands from an expression tree of only min/max operations if they
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* can be proven to not contribute to the final result.
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*
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* The algorithm is similar to alpha-beta pruning on a minmax search.
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*/
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#include "ir.h"
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#include "ir_visitor.h"
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#include "ir_rvalue_visitor.h"
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#include "ir_optimization.h"
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#include "ir_builder.h"
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#include "program/prog_instruction.h"
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#include "compiler/glsl_types.h"
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#include "main/macros.h"
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using namespace ir_builder;
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namespace {
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enum compare_components_result {
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LESS,
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LESS_OR_EQUAL,
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EQUAL,
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GREATER_OR_EQUAL,
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GREATER,
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MIXED
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};
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class minmax_range {
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public:
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minmax_range(ir_constant *low = NULL, ir_constant *high = NULL)
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{
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this->low = low;
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this->high = high;
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}
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/* low is the lower limit of the range, high is the higher limit. NULL on
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* low means negative infinity (unlimited) and on high positive infinity
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* (unlimited). Because of the two interpretations of the value NULL,
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* arbitrary comparison between ir_constants is impossible.
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*/
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ir_constant *low;
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ir_constant *high;
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};
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class ir_minmax_visitor : public ir_rvalue_enter_visitor {
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public:
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ir_minmax_visitor()
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: progress(false)
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{
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}
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ir_rvalue *prune_expression(ir_expression *expr, minmax_range baserange);
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void handle_rvalue(ir_rvalue **rvalue);
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bool progress;
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};
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/*
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* Returns LESS if all vector components of `a' are strictly lower than of `b',
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* GREATER if all vector components of `a' are strictly greater than of `b',
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* MIXED if some vector components of `a' are strictly lower than of `b' while
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* others are strictly greater, or EQUAL otherwise.
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*/
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static enum compare_components_result
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compare_components(ir_constant *a, ir_constant *b)
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{
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assert(a != NULL);
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assert(b != NULL);
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assert(a->type->base_type == b->type->base_type);
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unsigned a_inc = a->type->is_scalar() ? 0 : 1;
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unsigned b_inc = b->type->is_scalar() ? 0 : 1;
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unsigned components = MAX2(a->type->components(), b->type->components());
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bool foundless = false;
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bool foundgreater = false;
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bool foundequal = false;
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for (unsigned i = 0, c0 = 0, c1 = 0;
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i < components;
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c0 += a_inc, c1 += b_inc, ++i) {
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switch (a->type->base_type) {
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case GLSL_TYPE_UINT:
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if (a->value.u[c0] < b->value.u[c1])
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foundless = true;
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else if (a->value.u[c0] > b->value.u[c1])
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foundgreater = true;
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else
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foundequal = true;
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break;
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case GLSL_TYPE_INT:
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if (a->value.i[c0] < b->value.i[c1])
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foundless = true;
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else if (a->value.i[c0] > b->value.i[c1])
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foundgreater = true;
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else
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foundequal = true;
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break;
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case GLSL_TYPE_FLOAT:
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if (a->value.f[c0] < b->value.f[c1])
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foundless = true;
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else if (a->value.f[c0] > b->value.f[c1])
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foundgreater = true;
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else
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foundequal = true;
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break;
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case GLSL_TYPE_DOUBLE:
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if (a->value.d[c0] < b->value.d[c1])
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foundless = true;
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else if (a->value.d[c0] > b->value.d[c1])
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foundgreater = true;
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else
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foundequal = true;
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break;
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default:
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unreachable("not reached");
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}
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}
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if (foundless && foundgreater) {
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/* Some components are strictly lower, others are strictly greater */
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return MIXED;
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}
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if (foundequal) {
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/* It is not mixed, but it is not strictly lower or greater */
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if (foundless)
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return LESS_OR_EQUAL;
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if (foundgreater)
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return GREATER_OR_EQUAL;
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return EQUAL;
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}
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/* All components are strictly lower or strictly greater */
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return foundless ? LESS : GREATER;
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}
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static ir_constant *
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combine_constant(bool ismin, ir_constant *a, ir_constant *b)
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{
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void *mem_ctx = ralloc_parent(a);
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ir_constant *c = a->clone(mem_ctx, NULL);
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for (unsigned i = 0; i < c->type->components(); i++) {
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switch (c->type->base_type) {
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case GLSL_TYPE_UINT:
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if ((ismin && b->value.u[i] < c->value.u[i]) ||
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(!ismin && b->value.u[i] > c->value.u[i]))
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c->value.u[i] = b->value.u[i];
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break;
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case GLSL_TYPE_INT:
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if ((ismin && b->value.i[i] < c->value.i[i]) ||
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(!ismin && b->value.i[i] > c->value.i[i]))
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c->value.i[i] = b->value.i[i];
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break;
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case GLSL_TYPE_FLOAT:
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if ((ismin && b->value.f[i] < c->value.f[i]) ||
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(!ismin && b->value.f[i] > c->value.f[i]))
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c->value.f[i] = b->value.f[i];
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break;
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case GLSL_TYPE_DOUBLE:
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if ((ismin && b->value.d[i] < c->value.d[i]) ||
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(!ismin && b->value.d[i] > c->value.d[i]))
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c->value.d[i] = b->value.d[i];
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break;
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default:
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assert(!"not reached");
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}
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}
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return c;
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}
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static ir_constant *
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smaller_constant(ir_constant *a, ir_constant *b)
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{
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assert(a != NULL);
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assert(b != NULL);
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enum compare_components_result ret = compare_components(a, b);
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if (ret == MIXED)
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return combine_constant(true, a, b);
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else if (ret < EQUAL)
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return a;
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else
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return b;
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}
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static ir_constant *
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larger_constant(ir_constant *a, ir_constant *b)
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{
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assert(a != NULL);
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assert(b != NULL);
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enum compare_components_result ret = compare_components(a, b);
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if (ret == MIXED)
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return combine_constant(false, a, b);
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else if (ret < EQUAL)
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return b;
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else
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return a;
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}
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/* Combines two ranges by doing an element-wise min() / max() depending on the
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* operation.
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*/
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static minmax_range
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combine_range(minmax_range r0, minmax_range r1, bool ismin)
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{
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minmax_range ret;
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if (!r0.low) {
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ret.low = ismin ? r0.low : r1.low;
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} else if (!r1.low) {
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ret.low = ismin ? r1.low : r0.low;
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} else {
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ret.low = ismin ? smaller_constant(r0.low, r1.low) :
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larger_constant(r0.low, r1.low);
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}
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if (!r0.high) {
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ret.high = ismin ? r1.high : r0.high;
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} else if (!r1.high) {
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ret.high = ismin ? r0.high : r1.high;
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} else {
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ret.high = ismin ? smaller_constant(r0.high, r1.high) :
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larger_constant(r0.high, r1.high);
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}
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return ret;
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}
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/* Returns a range so that lower limit is the larger of the two lower limits,
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* and higher limit is the smaller of the two higher limits.
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*/
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static minmax_range
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range_intersection(minmax_range r0, minmax_range r1)
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{
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minmax_range ret;
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if (!r0.low)
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ret.low = r1.low;
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else if (!r1.low)
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ret.low = r0.low;
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else
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ret.low = larger_constant(r0.low, r1.low);
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if (!r0.high)
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ret.high = r1.high;
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else if (!r1.high)
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ret.high = r0.high;
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else
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ret.high = smaller_constant(r0.high, r1.high);
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return ret;
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}
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static minmax_range
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get_range(ir_rvalue *rval)
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{
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ir_expression *expr = rval->as_expression();
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if (expr && (expr->operation == ir_binop_min ||
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expr->operation == ir_binop_max)) {
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minmax_range r0 = get_range(expr->operands[0]);
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minmax_range r1 = get_range(expr->operands[1]);
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return combine_range(r0, r1, expr->operation == ir_binop_min);
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}
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ir_constant *c = rval->as_constant();
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if (c) {
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return minmax_range(c, c);
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}
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return minmax_range();
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}
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/**
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* Prunes a min/max expression considering the base range of the parent
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* min/max expression.
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*
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* @param baserange the range that the parents of this min/max expression
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* in the min/max tree will clamp its value to.
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*/
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ir_rvalue *
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ir_minmax_visitor::prune_expression(ir_expression *expr, minmax_range baserange)
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{
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assert(expr->operation == ir_binop_min ||
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expr->operation == ir_binop_max);
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bool ismin = expr->operation == ir_binop_min;
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minmax_range limits[2];
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/* Recurse to get the ranges for each of the subtrees of this
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* expression. We need to do this as a separate step because we need to
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* know the ranges of each of the subtrees before we prune either one.
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* Consider something like this:
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*
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* max
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* / \
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* max max
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* / \ / \
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* 3 a b 2
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*
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* We would like to prune away the max on the bottom-right, but to do so
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* we need to know the range of the expression on the left beforehand,
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* and there's no guarantee that we will visit either subtree in a
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* particular order.
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*/
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for (unsigned i = 0; i < 2; ++i)
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limits[i] = get_range(expr->operands[i]);
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for (unsigned i = 0; i < 2; ++i) {
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bool is_redundant = false;
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enum compare_components_result cr = LESS;
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if (ismin) {
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/* If this operand will always be greater than the other one, it's
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* redundant.
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*/
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if (limits[i].low && limits[1 - i].high) {
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cr = compare_components(limits[i].low, limits[1 - i].high);
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if (cr >= EQUAL && cr != MIXED)
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is_redundant = true;
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}
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/* If this operand is always greater than baserange, then even if
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* it's smaller than the other one it'll get clamped, so it's
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* redundant.
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*/
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if (!is_redundant && limits[i].low && baserange.high) {
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cr = compare_components(limits[i].low, baserange.high);
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if (cr >= EQUAL && cr != MIXED)
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is_redundant = true;
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}
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} else {
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/* If this operand will always be lower than the other one, it's
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* redundant.
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*/
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if (limits[i].high && limits[1 - i].low) {
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cr = compare_components(limits[i].high, limits[1 - i].low);
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if (cr <= EQUAL)
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is_redundant = true;
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}
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/* If this operand is always lower than baserange, then even if
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* it's greater than the other one it'll get clamped, so it's
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* redundant.
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*/
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if (!is_redundant && limits[i].high && baserange.low) {
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cr = compare_components(limits[i].high, baserange.low);
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if (cr <= EQUAL)
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is_redundant = true;
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}
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}
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if (is_redundant) {
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progress = true;
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/* Recurse if necessary. */
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ir_expression *op_expr = expr->operands[1 - i]->as_expression();
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if (op_expr && (op_expr->operation == ir_binop_min ||
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op_expr->operation == ir_binop_max)) {
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return prune_expression(op_expr, baserange);
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}
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return expr->operands[1 - i];
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} else if (cr == MIXED) {
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/* If we have mixed vector operands, we can try to resolve the minmax
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* expression by doing a component-wise minmax:
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*
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* min min
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* / \ / \
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* min a ===> [1,1] a
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* / \
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* [1,3] [3,1]
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*
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*/
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ir_constant *a = expr->operands[0]->as_constant();
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ir_constant *b = expr->operands[1]->as_constant();
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if (a && b)
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return combine_constant(ismin, a, b);
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}
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}
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/* Now recurse to operands giving them the proper baserange. The baserange
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* to pass is the intersection of our baserange and the other operand's
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* limit with one of the ranges unlimited. If we can't compute a valid
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* intersection, we use the current baserange.
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*/
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for (unsigned i = 0; i < 2; ++i) {
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ir_expression *op_expr = expr->operands[i]->as_expression();
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if (op_expr && (op_expr->operation == ir_binop_min ||
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op_expr->operation == ir_binop_max)) {
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/* We can only compute a new baserange for this operand if we managed
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* to compute a valid range for the other operand.
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*/
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if (ismin)
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limits[1 - i].low = NULL;
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else
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limits[1 - i].high = NULL;
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minmax_range base = range_intersection(limits[1 - i], baserange);
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expr->operands[i] = prune_expression(op_expr, base);
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}
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}
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/* If we got here we could not discard any of the operands of the minmax
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* expression, but we can still try to resolve the expression if both
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* operands are constant. We do this after the loop above, to make sure
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* that if our operands are minmax expressions we have tried to prune them
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* first (hopefully reducing them to constants).
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*/
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ir_constant *a = expr->operands[0]->as_constant();
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ir_constant *b = expr->operands[1]->as_constant();
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if (a && b)
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return combine_constant(ismin, a, b);
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return expr;
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}
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static ir_rvalue *
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swizzle_if_required(ir_expression *expr, ir_rvalue *rval)
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{
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if (expr->type->is_vector() && rval->type->is_scalar()) {
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return swizzle(rval, SWIZZLE_XXXX, expr->type->vector_elements);
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} else {
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return rval;
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}
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}
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void
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ir_minmax_visitor::handle_rvalue(ir_rvalue **rvalue)
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{
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if (!*rvalue)
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return;
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ir_expression *expr = (*rvalue)->as_expression();
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if (!expr || (expr->operation != ir_binop_min &&
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expr->operation != ir_binop_max))
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return;
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ir_rvalue *new_rvalue = prune_expression(expr, minmax_range());
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if (new_rvalue == *rvalue)
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return;
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/* If the expression type is a vector and the optimization leaves a scalar
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* as the result, we need to turn it into a vector.
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*/
|
||||
*rvalue = swizzle_if_required(expr, new_rvalue);
|
||||
|
||||
progress = true;
|
||||
}
|
||||
|
||||
}
|
||||
|
||||
bool
|
||||
do_minmax_prune(exec_list *instructions)
|
||||
{
|
||||
ir_minmax_visitor v;
|
||||
|
||||
visit_list_elements(&v, instructions);
|
||||
|
||||
return v.progress;
|
||||
}
|
Reference in New Issue
Block a user