X-Git-Url: https://git.libre-soc.org/?a=blobdiff_plain;f=src%2Fglsl%2Flower_instructions.cpp;h=684285350d05a685270b3da79eb9a2d836c76602;hb=153b8b35257fb5d68735b5e43e48b0cdb8b15170;hp=d460ba1a97abd2d3fe00f368c2ef5eba4f0e7d55;hpb=63684a9ae7a66f68df1f2c68cd9358e5622122a3;p=mesa.git diff --git a/src/glsl/lower_instructions.cpp b/src/glsl/lower_instructions.cpp index d460ba1a97a..684285350d0 100644 --- a/src/glsl/lower_instructions.cpp +++ b/src/glsl/lower_instructions.cpp @@ -32,9 +32,16 @@ * 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_FRACT + * - LDEXP_TO_ARITH + * - BITFIELD_INSERT_TO_BFM_BFI + * - CARRY_TO_ARITH + * - BORROW_TO_ARITH + * - SAT_TO_CLAMP * * SUB_TO_ADD_NEG: * --------------- @@ -46,35 +53,74 @@ * want to recognize add(op0, neg(op1)) or the other way around to * produce a subtract anyway. * - * DIV_TO_MUL_RCP: - * --------------- - * Breaks an ir_unop_div expression down to op0 * (rcp(op1)). + * 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_FRACT: * ------------- - * Breaks an ir_unop_mod expression down to (op1 * fract(op0 / op1)) + * Breaks an ir_binop_mod expression down to (op1 * fract(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. + * + * LDEXP_TO_ARITH: + * ------------- + * Converts ir_binop_ldexp to arithmetic and bit operations. + * + * 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) + * */ -#include "main/core.h" /* for M_E */ +#include "main/core.h" /* for M_LOG2E */ #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) @@ -89,11 +135,20 @@ private: 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_fract(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 carry_to_arith(ir_expression *); + void borrow_to_arith(ir_expression *); + void sat_to_clamp(ir_expression *); }; +} /* anonymous namespace */ + /** * Determine if a particular type of lowering should occur */ @@ -120,51 +175,67 @@ lower_instructions_visitor::sub_to_add_neg(ir_expression *ir) void lower_instructions_visitor::div_to_mul_rcp(ir_expression *ir) { - if (!ir->operands[1]->type->is_integer()) { - /* 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], - NULL); - - /* op0 / op1 -> op0 * (1.0 / op1) */ - ir->operation = ir_binop_mul; - ir->operands[1] = expr; - } else { - /* 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; + assert(ir->operands[1]->type->is_float()); + + /* 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); - 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); - 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); - 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); - 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); - 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); + 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; - ir->operands[1] = NULL; + } else { + ir->operation = ir_unop_i2u; + ir->operands[0] = new(ir) ir_expression(ir_unop_f2i, op0); } + ir->operands[1] = NULL; this->progress = true; } @@ -172,7 +243,7 @@ lower_instructions_visitor::div_to_mul_rcp(ir_expression *ir) void lower_instructions_visitor::exp_to_exp2(ir_expression *ir) { - ir_constant *log2_e = new(ir) ir_constant(log2f(M_E)); + 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, @@ -180,13 +251,27 @@ lower_instructions_visitor::exp_to_exp2(ir_expression *ir) 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(1.0f / log2f(M_E)); + ir->operands[1] = new(ir) ir_constant(float(1.0 / M_LOG2E)); this->progress = true; } @@ -225,6 +310,204 @@ lower_instructions_visitor::mod_to_fract(ir_expression *ir) 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 and 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 . */ + 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::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; +} + ir_visitor_status lower_instructions_visitor::visit_leave(ir_expression *ir) { @@ -235,7 +518,9 @@ lower_instructions_visitor::visit_leave(ir_expression *ir) break; case ir_binop_div: - if (lowering(DIV_TO_MUL_RCP)) + 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() && lowering(DIV_TO_MUL_RCP)) div_to_mul_rcp(ir); break; @@ -250,10 +535,40 @@ lower_instructions_visitor::visit_leave(ir_expression *ir) break; case ir_binop_mod: - if (lowering(MOD_TO_FRACT)) + if (lowering(MOD_TO_FRACT) && ir->type->is_float()) mod_to_fract(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)) + ldexp_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; + default: return visit_continue; }