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Diffstat (limited to 'src/compiler/glsl/lower_instructions.cpp')
| -rw-r--r-- | src/compiler/glsl/lower_instructions.cpp | 1061 |
1 files changed, 1061 insertions, 0 deletions
diff --git a/src/compiler/glsl/lower_instructions.cpp b/src/compiler/glsl/lower_instructions.cpp new file mode 100644 index 00000000000..1875149b7a6 --- /dev/null +++ b/src/compiler/glsl/lower_instructions.cpp @@ -0,0 +1,1061 @@ +/* + * 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 + * - 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. + * + * 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 "compiler/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 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::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, vec_elem); + ir_constant *exp_width = new(ir) ir_constant(8, 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])); + + /* 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; + + 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(20u); + ir_constant *exp_width = new(ir) ir_constant(11u); + 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)); + + 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_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; +} |