/*
* Copyright © 2010 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 lower_instructions.cpp
*
* Many GPUs lack native instructions for certain expression operations, and
* must replace them with some other expression tree. This pass lowers some
* of the most common cases, allowing the lowering code to be implemented once
* rather than in each driver backend.
*
* Currently supported transformations:
* - SUB_TO_ADD_NEG
* - DIV_TO_MUL_RCP
* - INT_DIV_TO_MUL_RCP
* - EXP_TO_EXP2
* - POW_TO_EXP2
* - LOG_TO_LOG2
* - MOD_TO_FLOOR
* - LDEXP_TO_ARITH
* - DFREXP_TO_ARITH
* - BITFIELD_INSERT_TO_BFM_BFI
* - CARRY_TO_ARITH
* - BORROW_TO_ARITH
* - SAT_TO_CLAMP
* - DOPS_TO_DFRAC
*
* SUB_TO_ADD_NEG:
* ---------------
* Breaks an ir_binop_sub expression down to add(op0, neg(op1))
*
* This simplifies expression reassociation, and for many backends
* there is no subtract operation separate from adding the negation.
* For backends with native subtract operations, they will probably
* want to recognize add(op0, neg(op1)) or the other way around to
* produce a subtract anyway.
*
* DIV_TO_MUL_RCP and INT_DIV_TO_MUL_RCP:
* --------------------------------------
* Breaks an ir_binop_div expression down to op0 * (rcp(op1)).
*
* Many GPUs don't have a divide instruction (945 and 965 included),
* but they do have an RCP instruction to compute an approximate
* reciprocal. By breaking the operation down, constant reciprocals
* can get constant folded.
*
* DIV_TO_MUL_RCP only lowers floating point division; INT_DIV_TO_MUL_RCP
* handles the integer case, converting to and from floating point so that
* RCP is possible.
*
* EXP_TO_EXP2 and LOG_TO_LOG2:
* ----------------------------
* Many GPUs don't have a base e log or exponent instruction, but they
* do have base 2 versions, so this pass converts exp and log to exp2
* and log2 operations.
*
* POW_TO_EXP2:
* -----------
* Many older GPUs don't have an x**y instruction. For these GPUs, convert
* x**y to 2**(y * log2(x)).
*
* MOD_TO_FLOOR:
* -------------
* Breaks an ir_binop_mod expression down to (op0 - op1 * floor(op0 / op1))
*
* Many GPUs don't have a MOD instruction (945 and 965 included), and
* if we have to break it down like this anyway, it gives an
* opportunity to do things like constant fold the (1.0 / op1) easily.
*
* Note: before we used to implement this as op1 * fract(op / op1) but this
* implementation had significant precision errors.
*
* LDEXP_TO_ARITH:
* -------------
* Converts ir_binop_ldexp to arithmetic and bit operations for float sources.
*
* DFREXP_DLDEXP_TO_ARITH:
* ---------------
* Converts ir_binop_ldexp, ir_unop_frexp_sig, and ir_unop_frexp_exp to
* arithmetic and bit ops for double arguments.
*
* BITFIELD_INSERT_TO_BFM_BFI:
* ---------------------------
* Breaks ir_quadop_bitfield_insert into ir_binop_bfm (bitfield mask) and
* ir_triop_bfi (bitfield insert).
*
* Many GPUs implement the bitfieldInsert() built-in from ARB_gpu_shader_5
* with a pair of instructions.
*
* CARRY_TO_ARITH:
* ---------------
* Converts ir_carry into (x + y) < x.
*
* BORROW_TO_ARITH:
* ----------------
* Converts ir_borrow into (x < y).
*
* SAT_TO_CLAMP:
* -------------
* Converts ir_unop_saturate into min(max(x, 0.0), 1.0)
*
* DOPS_TO_DFRAC:
* --------------
* Converts double trunc, ceil, floor, round to fract
*/
#include "c99_math.h"
#include "program/prog_instruction.h" /* for swizzle */
#include "glsl_types.h"
#include "ir.h"
#include "ir_builder.h"
#include "ir_optimization.h"
using namespace ir_builder;
namespace {
class lower_instructions_visitor : public ir_hierarchical_visitor {
public:
lower_instructions_visitor(unsigned lower)
: progress(false), lower(lower) { }
ir_visitor_status visit_leave(ir_expression *);
bool progress;
private:
unsigned lower; /** Bitfield of which operations to lower */
void sub_to_add_neg(ir_expression *);
void div_to_mul_rcp(ir_expression *);
void int_div_to_mul_rcp(ir_expression *);
void mod_to_floor(ir_expression *);
void exp_to_exp2(ir_expression *);
void pow_to_exp2(ir_expression *);
void log_to_log2(ir_expression *);
void bitfield_insert_to_bfm_bfi(ir_expression *);
void ldexp_to_arith(ir_expression *);
void dldexp_to_arith(ir_expression *);
void dfrexp_sig_to_arith(ir_expression *);
void dfrexp_exp_to_arith(ir_expression *);
void carry_to_arith(ir_expression *);
void borrow_to_arith(ir_expression *);
void sat_to_clamp(ir_expression *);
void double_dot_to_fma(ir_expression *);
void double_lrp(ir_expression *);
void dceil_to_dfrac(ir_expression *);
void dfloor_to_dfrac(ir_expression *);
void dround_even_to_dfrac(ir_expression *);
void dtrunc_to_dfrac(ir_expression *);
void dsign_to_csel(ir_expression *);
};
} /* anonymous namespace */
/**
* Determine if a particular type of lowering should occur
*/
#define lowering(x) (this->lower & x)
bool
lower_instructions(exec_list *instructions, unsigned what_to_lower)
{
lower_instructions_visitor v(what_to_lower);
visit_list_elements(&v, instructions);
return v.progress;
}
void
lower_instructions_visitor::sub_to_add_neg(ir_expression *ir)
{
ir->operation = ir_binop_add;
ir->operands[1] = new(ir) ir_expression(ir_unop_neg, ir->operands[1]->type,
ir->operands[1], NULL);
this->progress = true;
}
void
lower_instructions_visitor::div_to_mul_rcp(ir_expression *ir)
{
assert(ir->operands[1]->type->is_float() || ir->operands[1]->type->is_double());
/* New expression for the 1.0 / op1 */
ir_rvalue *expr;
expr = new(ir) ir_expression(ir_unop_rcp,
ir->operands[1]->type,
ir->operands[1]);
/* op0 / op1 -> op0 * (1.0 / op1) */
ir->operation = ir_binop_mul;
ir->operands[1] = expr;
this->progress = true;
}
void
lower_instructions_visitor::int_div_to_mul_rcp(ir_expression *ir)
{
assert(ir->operands[1]->type->is_integer());
/* Be careful with integer division -- we need to do it as a
* float and re-truncate, since rcp(n > 1) of an integer would
* just be 0.
*/
ir_rvalue *op0, *op1;
const struct glsl_type *vec_type;
vec_type = glsl_type::get_instance(GLSL_TYPE_FLOAT,
ir->operands[1]->type->vector_elements,
ir->operands[1]->type->matrix_columns);
if (ir->operands[1]->type->base_type == GLSL_TYPE_INT)
op1 = new(ir) ir_expression(ir_unop_i2f, vec_type, ir->operands[1], NULL);
else
op1 = new(ir) ir_expression(ir_unop_u2f, vec_type, ir->operands[1], NULL);
op1 = new(ir) ir_expression(ir_unop_rcp, op1->type, op1, NULL);
vec_type = glsl_type::get_instance(GLSL_TYPE_FLOAT,
ir->operands[0]->type->vector_elements,
ir->operands[0]->type->matrix_columns);
if (ir->operands[0]->type->base_type == GLSL_TYPE_INT)
op0 = new(ir) ir_expression(ir_unop_i2f, vec_type, ir->operands[0], NULL);
else
op0 = new(ir) ir_expression(ir_unop_u2f, vec_type, ir->operands[0], NULL);
vec_type = glsl_type::get_instance(GLSL_TYPE_FLOAT,
ir->type->vector_elements,
ir->type->matrix_columns);
op0 = new(ir) ir_expression(ir_binop_mul, vec_type, op0, op1);
if (ir->operands[1]->type->base_type == GLSL_TYPE_INT) {
ir->operation = ir_unop_f2i;
ir->operands[0] = op0;
} else {
ir->operation = ir_unop_i2u;
ir->operands[0] = new(ir) ir_expression(ir_unop_f2i, op0);
}
ir->operands[1] = NULL;
this->progress = true;
}
void
lower_instructions_visitor::exp_to_exp2(ir_expression *ir)
{
ir_constant *log2_e = new(ir) ir_constant(float(M_LOG2E));
ir->operation = ir_unop_exp2;
ir->operands[0] = new(ir) ir_expression(ir_binop_mul, ir->operands[0]->type,
ir->operands[0], log2_e);
this->progress = true;
}
void
lower_instructions_visitor::pow_to_exp2(ir_expression *ir)
{
ir_expression *const log2_x =
new(ir) ir_expression(ir_unop_log2, ir->operands[0]->type,
ir->operands[0]);
ir->operation = ir_unop_exp2;
ir->operands[0] = new(ir) ir_expression(ir_binop_mul, ir->operands[1]->type,
ir->operands[1], log2_x);
ir->operands[1] = NULL;
this->progress = true;
}
void
lower_instructions_visitor::log_to_log2(ir_expression *ir)
{
ir->operation = ir_binop_mul;
ir->operands[0] = new(ir) ir_expression(ir_unop_log2, ir->operands[0]->type,
ir->operands[0], NULL);
ir->operands[1] = new(ir) ir_constant(float(1.0 / M_LOG2E));
this->progress = true;
}
void
lower_instructions_visitor::mod_to_floor(ir_expression *ir)
{
ir_variable *x = new(ir) ir_variable(ir->operands[0]->type, "mod_x",
ir_var_temporary);
ir_variable *y = new(ir) ir_variable(ir->operands[1]->type, "mod_y",
ir_var_temporary);
this->base_ir->insert_before(x);
this->base_ir->insert_before(y);
ir_assignment *const assign_x =
new(ir) ir_assignment(new(ir) ir_dereference_variable(x),
ir->operands[0], NULL);
ir_assignment *const assign_y =
new(ir) ir_assignment(new(ir) ir_dereference_variable(y),
ir->operands[1], NULL);
this->base_ir->insert_before(assign_x);
this->base_ir->insert_before(assign_y);
ir_expression *const div_expr =
new(ir) ir_expression(ir_binop_div, x->type,
new(ir) ir_dereference_variable(x),
new(ir) ir_dereference_variable(y));
/* Don't generate new IR that would need to be lowered in an additional
* pass.
*/
if (lowering(DIV_TO_MUL_RCP) && (ir->type->is_float() || ir->type->is_double()))
div_to_mul_rcp(div_expr);
ir_expression *const floor_expr =
new(ir) ir_expression(ir_unop_floor, x->type, div_expr);
if (lowering(DOPS_TO_DFRAC) && ir->type->is_double())
dfloor_to_dfrac(floor_expr);
ir_expression *const mul_expr =
new(ir) ir_expression(ir_binop_mul,
new(ir) ir_dereference_variable(y),
floor_expr);
ir->operation = ir_binop_sub;
ir->operands[0] = new(ir) ir_dereference_variable(x);
ir->operands[1] = mul_expr;
this->progress = true;
}
void
lower_instructions_visitor::bitfield_insert_to_bfm_bfi(ir_expression *ir)
{
/* Translates
* ir_quadop_bitfield_insert base insert offset bits
* into
* ir_triop_bfi (ir_binop_bfm bits offset) insert base
*/
ir_rvalue *base_expr = ir->operands[0];
ir->operation = ir_triop_bfi;
ir->operands[0] = new(ir) ir_expression(ir_binop_bfm,
ir->type->get_base_type(),
ir->operands[3],
ir->operands[2]);
/* ir->operands[1] is still the value to insert. */
ir->operands[2] = base_expr;
ir->operands[3] = NULL;
this->progress = true;
}
void
lower_instructions_visitor::ldexp_to_arith(ir_expression *ir)
{
/* Translates
* ir_binop_ldexp x exp
* into
*
* extracted_biased_exp = rshift(bitcast_f2i(abs(x)), exp_shift);
* resulting_biased_exp = extracted_biased_exp + exp;
*
* if (resulting_biased_exp < 1) {
* return copysign(0.0, x);
* }
*
* return bitcast_u2f((bitcast_f2u(x) & sign_mantissa_mask) |
* lshift(i2u(resulting_biased_exp), exp_shift));
*
* which we can't actually implement as such, since the GLSL IR doesn't
* have vectorized if-statements. We actually implement it without branches
* using conditional-select:
*
* extracted_biased_exp = rshift(bitcast_f2i(abs(x)), exp_shift);
* resulting_biased_exp = extracted_biased_exp + exp;
*
* is_not_zero_or_underflow = gequal(resulting_biased_exp, 1);
* x = csel(is_not_zero_or_underflow, x, copysign(0.0f, x));
* resulting_biased_exp = csel(is_not_zero_or_underflow,
* resulting_biased_exp, 0);
*
* return bitcast_u2f((bitcast_f2u(x) & sign_mantissa_mask) |
* lshift(i2u(resulting_biased_exp), exp_shift));
*/
const unsigned vec_elem = ir->type->vector_elements;
/* Types */
const glsl_type *ivec = glsl_type::get_instance(GLSL_TYPE_INT, vec_elem, 1);
const glsl_type *bvec = glsl_type::get_instance(GLSL_TYPE_BOOL, vec_elem, 1);
/* Constants */
ir_constant *zeroi = ir_constant::zero(ir, ivec);
ir_constant *sign_mask = new(ir) ir_constant(0x80000000u, vec_elem);
ir_constant *exp_shift = new(ir) ir_constant(23);
ir_constant *exp_width = new(ir) ir_constant(8);
/* Temporary variables */
ir_variable *x = new(ir) ir_variable(ir->type, "x", ir_var_temporary);
ir_variable *exp = new(ir) ir_variable(ivec, "exp", ir_var_temporary);
ir_variable *zero_sign_x = new(ir) ir_variable(ir->type, "zero_sign_x",
ir_var_temporary);
ir_variable *extracted_biased_exp =
new(ir) ir_variable(ivec, "extracted_biased_exp", ir_var_temporary);
ir_variable *resulting_biased_exp =
new(ir) ir_variable(ivec, "resulting_biased_exp", ir_var_temporary);
ir_variable *is_not_zero_or_underflow =
new(ir) ir_variable(bvec, "is_not_zero_or_underflow", ir_var_temporary);
ir_instruction &i = *base_ir;
/* Copy <x> and <exp> arguments. */
i.insert_before(x);
i.insert_before(assign(x, ir->operands[0]));
i.insert_before(exp);
i.insert_before(assign(exp, ir->operands[1]));
/* Extract the biased exponent from <x>. */
i.insert_before(extracted_biased_exp);
i.insert_before(assign(extracted_biased_exp,
rshift(bitcast_f2i(abs(x)), exp_shift)));
i.insert_before(resulting_biased_exp);
i.insert_before(assign(resulting_biased_exp,
add(extracted_biased_exp, exp)));
/* Test if result is ±0.0, subnormal, or underflow by checking if the
* resulting biased exponent would be less than 0x1. If so, the result is
* 0.0 with the sign of x. (Actually, invert the conditions so that
* immediate values are the second arguments, which is better for i965)
*/
i.insert_before(zero_sign_x);
i.insert_before(assign(zero_sign_x,
bitcast_u2f(bit_and(bitcast_f2u(x), sign_mask))));
i.insert_before(is_not_zero_or_underflow);
i.insert_before(assign(is_not_zero_or_underflow,
gequal(resulting_biased_exp,
new(ir) ir_constant(0x1, vec_elem))));
i.insert_before(assign(x, csel(is_not_zero_or_underflow,
x, zero_sign_x)));
i.insert_before(assign(resulting_biased_exp,
csel(is_not_zero_or_underflow,
resulting_biased_exp, zeroi)));
/* We could test for overflows by checking if the resulting biased exponent
* would be greater than 0xFE. Turns out we don't need to because the GLSL
* spec says:
*
* "If this product is too large to be represented in the
* floating-point type, the result is undefined."
*/
ir_constant *exp_shift_clone = exp_shift->clone(ir, NULL);
ir->operation = ir_unop_bitcast_i2f;
ir->operands[0] = bitfield_insert(bitcast_f2i(x), resulting_biased_exp,
exp_shift_clone, exp_width);
ir->operands[1] = NULL;
/* Don't generate new IR that would need to be lowered in an additional
* pass.
*/
if (lowering(BITFIELD_INSERT_TO_BFM_BFI))
bitfield_insert_to_bfm_bfi(ir->operands[0]->as_expression());
this->progress = true;
}
void
lower_instructions_visitor::dldexp_to_arith(ir_expression *ir)
{
/* See ldexp_to_arith for structure. Uses frexp_exp to extract the exponent
* from the significand.
*/
const unsigned vec_elem = ir->type->vector_elements;
/* Types */
const glsl_type *ivec = glsl_type::get_instance(GLSL_TYPE_INT, vec_elem, 1);
const glsl_type *bvec = glsl_type::get_instance(GLSL_TYPE_BOOL, vec_elem, 1);
/* Constants */
ir_constant *zeroi = ir_constant::zero(ir, ivec);
ir_constant *sign_mask = new(ir) ir_constant(0x80000000u);
ir_constant *exp_shift = new(ir) ir_constant(20);
ir_constant *exp_width = new(ir) ir_constant(11);
ir_constant *exp_bias = new(ir) ir_constant(1022, vec_elem);
/* Temporary variables */
ir_variable *x = new(ir) ir_variable(ir->type, "x", ir_var_temporary);
ir_variable *exp = new(ir) ir_variable(ivec, "exp", ir_var_temporary);
ir_variable *zero_sign_x = new(ir) ir_variable(ir->type, "zero_sign_x",
ir_var_temporary);
ir_variable *extracted_biased_exp =
new(ir) ir_variable(ivec, "extracted_biased_exp", ir_var_temporary);
ir_variable *resulting_biased_exp =
new(ir) ir_variable(ivec, "resulting_biased_exp", ir_var_temporary);
ir_variable *is_not_zero_or_underflow =
new(ir) ir_variable(bvec, "is_not_zero_or_underflow", ir_var_temporary);
ir_instruction &i = *base_ir;
/* Copy <x> and <exp> arguments. */
i.insert_before(x);
i.insert_before(assign(x, ir->operands[0]));
i.insert_before(exp);
i.insert_before(assign(exp, ir->operands[1]));
ir_expression *frexp_exp = expr(ir_unop_frexp_exp, x);
if (lowering(DFREXP_DLDEXP_TO_ARITH))
dfrexp_exp_to_arith(frexp_exp);
/* Extract the biased exponent from <x>. */
i.insert_before(extracted_biased_exp);
i.insert_before(assign(extracted_biased_exp, add(frexp_exp, exp_bias)));
i.insert_before(resulting_biased_exp);
i.insert_before(assign(resulting_biased_exp,
add(extracted_biased_exp, exp)));
/* Test if result is ±0.0, subnormal, or underflow by checking if the
* resulting biased exponent would be less than 0x1. If so, the result is
* 0.0 with the sign of x. (Actually, invert the conditions so that
* immediate values are the second arguments, which is better for i965)
* TODO: Implement in a vector fashion.
*/
i.insert_before(zero_sign_x);
for (unsigned elem = 0; elem < vec_elem; elem++) {
ir_variable *unpacked =
new(ir) ir_variable(glsl_type::uvec2_type, "unpacked", ir_var_temporary);
i.insert_before(unpacked);
i.insert_before(
assign(unpacked,
expr(ir_unop_unpack_double_2x32, swizzle(x, elem, 1))));
i.insert_before(assign(unpacked, bit_and(swizzle_y(unpacked), sign_mask->clone(ir, NULL)),
WRITEMASK_Y));
i.insert_before(assign(unpacked, ir_constant::zero(ir, glsl_type::uint_type), WRITEMASK_X));
i.insert_before(assign(zero_sign_x,
expr(ir_unop_pack_double_2x32, unpacked),
1 << elem));
}
i.insert_before(is_not_zero_or_underflow);
i.insert_before(assign(is_not_zero_or_underflow,
gequal(resulting_biased_exp,
new(ir) ir_constant(0x1, vec_elem))));
i.insert_before(assign(x, csel(is_not_zero_or_underflow,
x, zero_sign_x)));
i.insert_before(assign(resulting_biased_exp,
csel(is_not_zero_or_underflow,
resulting_biased_exp, zeroi)));
/* We could test for overflows by checking if the resulting biased exponent
* would be greater than 0xFE. Turns out we don't need to because the GLSL
* spec says:
*
* "If this product is too large to be represented in the
* floating-point type, the result is undefined."
*/
ir_rvalue *results[4] = {NULL};
for (unsigned elem = 0; elem < vec_elem; elem++) {
ir_variable *unpacked =
new(ir) ir_variable(glsl_type::uvec2_type, "unpacked", ir_var_temporary);
i.insert_before(unpacked);
i.insert_before(
assign(unpacked,
expr(ir_unop_unpack_double_2x32, swizzle(x, elem, 1))));
ir_expression *bfi = bitfield_insert(
swizzle_y(unpacked),
i2u(swizzle(resulting_biased_exp, elem, 1)),
exp_shift->clone(ir, NULL),
exp_width->clone(ir, NULL));
if (lowering(BITFIELD_INSERT_TO_BFM_BFI))
bitfield_insert_to_bfm_bfi(bfi);
i.insert_before(assign(unpacked, bfi, WRITEMASK_Y));
results[elem] = expr(ir_unop_pack_double_2x32, unpacked);
}
ir->operation = ir_quadop_vector;
ir->operands[0] = results[0];
ir->operands[1] = results[1];
ir->operands[2] = results[2];
ir->operands[3] = results[3];
/* Don't generate new IR that would need to be lowered in an additional
* pass.
*/
this->progress = true;
}
void
lower_instructions_visitor::dfrexp_sig_to_arith(ir_expression *ir)
{
const unsigned vec_elem = ir->type->vector_elements;
const glsl_type *bvec = glsl_type::get_instance(GLSL_TYPE_BOOL, vec_elem, 1);
/* Double-precision floating-point values are stored as
* 1 sign bit;
* 11 exponent bits;
* 52 mantissa bits.
*
* We're just extracting the significand here, so we only need to modify
* the upper 32-bit uint. Unfortunately we must extract each double
* independently as there is no vector version of unpackDouble.
*/
ir_instruction &i = *base_ir;
ir_variable *is_not_zero =
new(ir) ir_variable(bvec, "is_not_zero", ir_var_temporary);
ir_rvalue *results[4] = {NULL};
ir_constant *dzero = new(ir) ir_constant(0.0, vec_elem);
i.insert_before(is_not_zero);
i.insert_before(
assign(is_not_zero,
nequal(abs(ir->operands[0]->clone(ir, NULL)), dzero)));
/* TODO: Remake this as more vector-friendly when int64 support is
* available.
*/
for (unsigned elem = 0; elem < vec_elem; elem++) {
ir_constant *zero = new(ir) ir_constant(0u, 1);
ir_constant *sign_mantissa_mask = new(ir) ir_constant(0x800fffffu, 1);
/* Exponent of double floating-point values in the range [0.5, 1.0). */
ir_constant *exponent_value = new(ir) ir_constant(0x3fe00000u, 1);
ir_variable *bits =
new(ir) ir_variable(glsl_type::uint_type, "bits", ir_var_temporary);
ir_variable *unpacked =
new(ir) ir_variable(glsl_type::uvec2_type, "unpacked", ir_var_temporary);
ir_rvalue *x = swizzle(ir->operands[0]->clone(ir, NULL), elem, 1);
i.insert_before(bits);
i.insert_before(unpacked);
i.insert_before(assign(unpacked, expr(ir_unop_unpack_double_2x32, x)));
/* Manipulate the high uint to remove the exponent and replace it with
* either the default exponent or zero.
*/
i.insert_before(assign(bits, swizzle_y(unpacked)));
i.insert_before(assign(bits, bit_and(bits, sign_mantissa_mask)));
i.insert_before(assign(bits, bit_or(bits,
csel(swizzle(is_not_zero, elem, 1),
exponent_value,
zero))));
i.insert_before(assign(unpacked, bits, WRITEMASK_Y));
results[elem] = expr(ir_unop_pack_double_2x32, unpacked);
}
/* Put the dvec back together */
ir->operation = ir_quadop_vector;
ir->operands[0] = results[0];
ir->operands[1] = results[1];
ir->operands[2] = results[2];
ir->operands[3] = results[3];
this->progress = true;
}
void
lower_instructions_visitor::dfrexp_exp_to_arith(ir_expression *ir)
{
const unsigned vec_elem = ir->type->vector_elements;
const glsl_type *bvec = glsl_type::get_instance(GLSL_TYPE_BOOL, vec_elem, 1);
const glsl_type *uvec = glsl_type::get_instance(GLSL_TYPE_UINT, vec_elem, 1);
/* Double-precision floating-point values are stored as
* 1 sign bit;
* 11 exponent bits;
* 52 mantissa bits.
*
* We're just extracting the exponent here, so we only care about the upper
* 32-bit uint.
*/
ir_instruction &i = *base_ir;
ir_variable *is_not_zero =
new(ir) ir_variable(bvec, "is_not_zero", ir_var_temporary);
ir_variable *high_words =
new(ir) ir_variable(uvec, "high_words", ir_var_temporary);
ir_constant *dzero = new(ir) ir_constant(0.0, vec_elem);
ir_constant *izero = new(ir) ir_constant(0, vec_elem);
ir_rvalue *absval = abs(ir->operands[0]);
i.insert_before(is_not_zero);
i.insert_before(high_words);
i.insert_before(assign(is_not_zero, nequal(absval->clone(ir, NULL), dzero)));
/* Extract all of the upper uints. */
for (unsigned elem = 0; elem < vec_elem; elem++) {
ir_rvalue *x = swizzle(absval->clone(ir, NULL), elem, 1);
i.insert_before(assign(high_words,
swizzle_y(expr(ir_unop_unpack_double_2x32, x)),
1 << elem));
}
ir_constant *exponent_shift = new(ir) ir_constant(20, vec_elem);
ir_constant *exponent_bias = new(ir) ir_constant(-1022, vec_elem);
/* For non-zero inputs, shift the exponent down and apply bias. */
ir->operation = ir_triop_csel;
ir->operands[0] = new(ir) ir_dereference_variable(is_not_zero);
ir->operands[1] = add(exponent_bias, u2i(rshift(high_words, exponent_shift)));
ir->operands[2] = izero;
this->progress = true;
}
void
lower_instructions_visitor::carry_to_arith(ir_expression *ir)
{
/* Translates
* ir_binop_carry x y
* into
* sum = ir_binop_add x y
* bcarry = ir_binop_less sum x
* carry = ir_unop_b2i bcarry
*/
ir_rvalue *x_clone = ir->operands[0]->clone(ir, NULL);
ir->operation = ir_unop_i2u;
ir->operands[0] = b2i(less(add(ir->operands[0], ir->operands[1]), x_clone));
ir->operands[1] = NULL;
this->progress = true;
}
void
lower_instructions_visitor::borrow_to_arith(ir_expression *ir)
{
/* Translates
* ir_binop_borrow x y
* into
* bcarry = ir_binop_less x y
* carry = ir_unop_b2i bcarry
*/
ir->operation = ir_unop_i2u;
ir->operands[0] = b2i(less(ir->operands[0], ir->operands[1]));
ir->operands[1] = NULL;
this->progress = true;
}
void
lower_instructions_visitor::sat_to_clamp(ir_expression *ir)
{
/* Translates
* ir_unop_saturate x
* into
* ir_binop_min (ir_binop_max(x, 0.0), 1.0)
*/
ir->operation = ir_binop_min;
ir->operands[0] = new(ir) ir_expression(ir_binop_max, ir->operands[0]->type,
ir->operands[0],
new(ir) ir_constant(0.0f));
ir->operands[1] = new(ir) ir_constant(1.0f);
this->progress = true;
}
void
lower_instructions_visitor::double_dot_to_fma(ir_expression *ir)
{
ir_variable *temp = new(ir) ir_variable(ir->operands[0]->type->get_base_type(), "dot_res",
ir_var_temporary);
this->base_ir->insert_before(temp);
int nc = ir->operands[0]->type->components();
for (int i = nc - 1; i >= 1; i--) {
ir_assignment *assig;
if (i == (nc - 1)) {
assig = assign(temp, mul(swizzle(ir->operands[0]->clone(ir, NULL), i, 1),
swizzle(ir->operands[1]->clone(ir, NULL), i, 1)));
} else {
assig = assign(temp, fma(swizzle(ir->operands[0]->clone(ir, NULL), i, 1),
swizzle(ir->operands[1]->clone(ir, NULL), i, 1),
temp));
}
this->base_ir->insert_before(assig);
}
ir->operation = ir_triop_fma;
ir->operands[0] = swizzle(ir->operands[0], 0, 1);
ir->operands[1] = swizzle(ir->operands[1], 0, 1);
ir->operands[2] = new(ir) ir_dereference_variable(temp);
this->progress = true;
}
void
lower_instructions_visitor::double_lrp(ir_expression *ir)
{
int swizval;
ir_rvalue *op0 = ir->operands[0], *op2 = ir->operands[2];
ir_constant *one = new(ir) ir_constant(1.0, op2->type->vector_elements);
switch (op2->type->vector_elements) {
case 1:
swizval = SWIZZLE_XXXX;
break;
default:
assert(op0->type->vector_elements == op2->type->vector_elements);
swizval = SWIZZLE_XYZW;
break;
}
ir->operation = ir_triop_fma;
ir->operands[0] = swizzle(op2, swizval, op0->type->vector_elements);
ir->operands[2] = mul(sub(one, op2->clone(ir, NULL)), op0);
this->progress = true;
}
void
lower_instructions_visitor::dceil_to_dfrac(ir_expression *ir)
{
/*
* frtemp = frac(x);
* temp = sub(x, frtemp);
* result = temp + ((frtemp != 0.0) ? 1.0 : 0.0);
*/
ir_instruction &i = *base_ir;
ir_constant *zero = new(ir) ir_constant(0.0, ir->operands[0]->type->vector_elements);
ir_constant *one = new(ir) ir_constant(1.0, ir->operands[0]->type->vector_elements);
ir_variable *frtemp = new(ir) ir_variable(ir->operands[0]->type, "frtemp",
ir_var_temporary);
i.insert_before(frtemp);
i.insert_before(assign(frtemp, fract(ir->operands[0])));
ir->operation = ir_binop_add;
ir->operands[0] = sub(ir->operands[0]->clone(ir, NULL), frtemp);
ir->operands[1] = csel(nequal(frtemp, zero), one, zero->clone(ir, NULL));
this->progress = true;
}
void
lower_instructions_visitor::dfloor_to_dfrac(ir_expression *ir)
{
/*
* frtemp = frac(x);
* result = sub(x, frtemp);
*/
ir->operation = ir_binop_sub;
ir->operands[1] = fract(ir->operands[0]->clone(ir, NULL));
this->progress = true;
}
void
lower_instructions_visitor::dround_even_to_dfrac(ir_expression *ir)
{
/*
* insane but works
* temp = x + 0.5;
* frtemp = frac(temp);
* t2 = sub(temp, frtemp);
* if (frac(x) == 0.5)
* result = frac(t2 * 0.5) == 0 ? t2 : t2 - 1;
* else
* result = t2;
*/
ir_instruction &i = *base_ir;
ir_variable *frtemp = new(ir) ir_variable(ir->operands[0]->type, "frtemp",
ir_var_temporary);
ir_variable *temp = new(ir) ir_variable(ir->operands[0]->type, "temp",
ir_var_temporary);
ir_variable *t2 = new(ir) ir_variable(ir->operands[0]->type, "t2",
ir_var_temporary);
ir_constant *p5 = new(ir) ir_constant(0.5, ir->operands[0]->type->vector_elements);
ir_constant *one = new(ir) ir_constant(1.0, ir->operands[0]->type->vector_elements);
ir_constant *zero = new(ir) ir_constant(0.0, ir->operands[0]->type->vector_elements);
i.insert_before(temp);
i.insert_before(assign(temp, add(ir->operands[0], p5)));
i.insert_before(frtemp);
i.insert_before(assign(frtemp, fract(temp)));
i.insert_before(t2);
i.insert_before(assign(t2, sub(temp, frtemp)));
ir->operation = ir_triop_csel;
ir->operands[0] = equal(fract(ir->operands[0]->clone(ir, NULL)),
p5->clone(ir, NULL));
ir->operands[1] = csel(equal(fract(mul(t2, p5->clone(ir, NULL))),
zero),
t2,
sub(t2, one));
ir->operands[2] = new(ir) ir_dereference_variable(t2);
this->progress = true;
}
void
lower_instructions_visitor::dtrunc_to_dfrac(ir_expression *ir)
{
/*
* frtemp = frac(x);
* temp = sub(x, frtemp);
* result = x >= 0 ? temp : temp + (frtemp == 0.0) ? 0 : 1;
*/
ir_rvalue *arg = ir->operands[0];
ir_instruction &i = *base_ir;
ir_constant *zero = new(ir) ir_constant(0.0, arg->type->vector_elements);
ir_constant *one = new(ir) ir_constant(1.0, arg->type->vector_elements);
ir_variable *frtemp = new(ir) ir_variable(arg->type, "frtemp",
ir_var_temporary);
ir_variable *temp = new(ir) ir_variable(ir->operands[0]->type, "temp",
ir_var_temporary);
i.insert_before(frtemp);
i.insert_before(assign(frtemp, fract(arg)));
i.insert_before(temp);
i.insert_before(assign(temp, sub(arg->clone(ir, NULL), frtemp)));
ir->operation = ir_triop_csel;
ir->operands[0] = gequal(arg->clone(ir, NULL), zero);
ir->operands[1] = new (ir) ir_dereference_variable(temp);
ir->operands[2] = add(temp,
csel(equal(frtemp, zero->clone(ir, NULL)),
zero->clone(ir, NULL),
one));
this->progress = true;
}
void
lower_instructions_visitor::dsign_to_csel(ir_expression *ir)
{
/*
* temp = x > 0.0 ? 1.0 : 0.0;
* result = x < 0.0 ? -1.0 : temp;
*/
ir_rvalue *arg = ir->operands[0];
ir_constant *zero = new(ir) ir_constant(0.0, arg->type->vector_elements);
ir_constant *one = new(ir) ir_constant(1.0, arg->type->vector_elements);
ir_constant *neg_one = new(ir) ir_constant(-1.0, arg->type->vector_elements);
ir->operation = ir_triop_csel;
ir->operands[0] = less(arg->clone(ir, NULL),
zero->clone(ir, NULL));
ir->operands[1] = neg_one;
ir->operands[2] = csel(greater(arg, zero),
one,
zero->clone(ir, NULL));
this->progress = true;
}
ir_visitor_status
lower_instructions_visitor::visit_leave(ir_expression *ir)
{
switch (ir->operation) {
case ir_binop_dot:
if (ir->operands[0]->type->is_double())
double_dot_to_fma(ir);
break;
case ir_triop_lrp:
if (ir->operands[0]->type->is_double())
double_lrp(ir);
break;
case ir_binop_sub:
if (lowering(SUB_TO_ADD_NEG))
sub_to_add_neg(ir);
break;
case ir_binop_div:
if (ir->operands[1]->type->is_integer() && lowering(INT_DIV_TO_MUL_RCP))
int_div_to_mul_rcp(ir);
else if ((ir->operands[1]->type->is_float() ||
ir->operands[1]->type->is_double()) && lowering(DIV_TO_MUL_RCP))
div_to_mul_rcp(ir);
break;
case ir_unop_exp:
if (lowering(EXP_TO_EXP2))
exp_to_exp2(ir);
break;
case ir_unop_log:
if (lowering(LOG_TO_LOG2))
log_to_log2(ir);
break;
case ir_binop_mod:
if (lowering(MOD_TO_FLOOR) && (ir->type->is_float() || ir->type->is_double()))
mod_to_floor(ir);
break;
case ir_binop_pow:
if (lowering(POW_TO_EXP2))
pow_to_exp2(ir);
break;
case ir_quadop_bitfield_insert:
if (lowering(BITFIELD_INSERT_TO_BFM_BFI))
bitfield_insert_to_bfm_bfi(ir);
break;
case ir_binop_ldexp:
if (lowering(LDEXP_TO_ARITH) && ir->type->is_float())
ldexp_to_arith(ir);
if (lowering(DFREXP_DLDEXP_TO_ARITH) && ir->type->is_double())
dldexp_to_arith(ir);
break;
case ir_unop_frexp_exp:
if (lowering(DFREXP_DLDEXP_TO_ARITH) && ir->operands[0]->type->is_double())
dfrexp_exp_to_arith(ir);
break;
case ir_unop_frexp_sig:
if (lowering(DFREXP_DLDEXP_TO_ARITH) && ir->operands[0]->type->is_double())
dfrexp_sig_to_arith(ir);
break;
case ir_binop_carry:
if (lowering(CARRY_TO_ARITH))
carry_to_arith(ir);
break;
case ir_binop_borrow:
if (lowering(BORROW_TO_ARITH))
borrow_to_arith(ir);
break;
case ir_unop_saturate:
if (lowering(SAT_TO_CLAMP))
sat_to_clamp(ir);
break;
case ir_unop_trunc:
if (lowering(DOPS_TO_DFRAC) && ir->type->is_double())
dtrunc_to_dfrac(ir);
break;
case ir_unop_ceil:
if (lowering(DOPS_TO_DFRAC) && ir->type->is_double())
dceil_to_dfrac(ir);
break;
case ir_unop_floor:
if (lowering(DOPS_TO_DFRAC) && ir->type->is_double())
dfloor_to_dfrac(ir);
break;
case ir_unop_round_even:
if (lowering(DOPS_TO_DFRAC) && ir->type->is_double())
dround_even_to_dfrac(ir);
break;
case ir_unop_sign:
if (lowering(DOPS_TO_DFRAC) && ir->type->is_double())
dsign_to_csel(ir);
break;
default:
return visit_continue;
}
return visit_continue;
}