| /* |
| * Copyright © 2010 Intel Corporation |
| * Copyright © 2018 Broadcom |
| * |
| * 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. |
| */ |
| |
| #include "nir.h" |
| #include "nir_builder.h" |
| |
| /** nir_lower_alu.c |
| * |
| * NIR's home for miscellaneous ALU operation lowering implementations. |
| * |
| * Most NIR ALU lowering occurs in nir_opt_algebraic.py, since it's generally |
| * easy to write them there. However, if terms appear multiple times in the |
| * lowered code, it can get very verbose and cause a lot of work for CSE, so |
| * it may end up being easier to write out in C code. |
| * |
| * The shader must be in SSA for this pass. |
| */ |
| |
| static bool |
| lower_alu_instr(nir_builder *b, nir_alu_instr *instr, UNUSED void *cb_data) |
| { |
| nir_def *lowered = NULL; |
| |
| b->cursor = nir_before_instr(&instr->instr); |
| b->exact = instr->exact; |
| b->fp_fast_math = instr->fp_fast_math; |
| |
| switch (instr->op) { |
| case nir_op_bitfield_reverse: |
| if (b->shader->options->lower_bitfield_reverse) { |
| /* For more details, see: |
| * |
| * http://graphics.stanford.edu/~seander/bithacks.html#ReverseParallel |
| */ |
| nir_def *c1 = nir_imm_int(b, 1); |
| nir_def *c2 = nir_imm_int(b, 2); |
| nir_def *c4 = nir_imm_int(b, 4); |
| nir_def *c8 = nir_imm_int(b, 8); |
| nir_def *c16 = nir_imm_int(b, 16); |
| nir_def *c33333333 = nir_imm_int(b, 0x33333333); |
| nir_def *c55555555 = nir_imm_int(b, 0x55555555); |
| nir_def *c0f0f0f0f = nir_imm_int(b, 0x0f0f0f0f); |
| nir_def *c00ff00ff = nir_imm_int(b, 0x00ff00ff); |
| |
| lowered = nir_ssa_for_alu_src(b, instr, 0); |
| |
| /* Swap odd and even bits. */ |
| lowered = nir_ior(b, |
| nir_iand(b, nir_ushr(b, lowered, c1), c55555555), |
| nir_ishl(b, nir_iand(b, lowered, c55555555), c1)); |
| |
| /* Swap consecutive pairs. */ |
| lowered = nir_ior(b, |
| nir_iand(b, nir_ushr(b, lowered, c2), c33333333), |
| nir_ishl(b, nir_iand(b, lowered, c33333333), c2)); |
| |
| /* Swap nibbles. */ |
| lowered = nir_ior(b, |
| nir_iand(b, nir_ushr(b, lowered, c4), c0f0f0f0f), |
| nir_ishl(b, nir_iand(b, lowered, c0f0f0f0f), c4)); |
| |
| /* Swap bytes. */ |
| lowered = nir_ior(b, |
| nir_iand(b, nir_ushr(b, lowered, c8), c00ff00ff), |
| nir_ishl(b, nir_iand(b, lowered, c00ff00ff), c8)); |
| |
| lowered = nir_ior(b, |
| nir_ushr(b, lowered, c16), |
| nir_ishl(b, lowered, c16)); |
| } |
| break; |
| |
| case nir_op_bit_count: |
| if (b->shader->options->lower_bit_count) { |
| /* For more details, see: |
| * |
| * http://graphics.stanford.edu/~seander/bithacks.html#CountBitsSetParallel |
| */ |
| |
| lowered = nir_ssa_for_alu_src(b, instr, 0); |
| unsigned bit_size = lowered->bit_size; |
| |
| nir_def *c1 = nir_imm_int(b, 1); |
| nir_def *c2 = nir_imm_int(b, 2); |
| nir_def *c4 = nir_imm_int(b, 4); |
| nir_def *cshift = nir_imm_int(b, bit_size - 8); |
| nir_def *c33333333 = nir_imm_intN_t(b, 0x33333333, bit_size); |
| nir_def *c55555555 = nir_imm_intN_t(b, 0x55555555, bit_size); |
| nir_def *c0f0f0f0f = nir_imm_intN_t(b, 0x0f0f0f0f, bit_size); |
| nir_def *c01010101 = nir_imm_intN_t(b, 0x01010101, bit_size); |
| |
| |
| lowered = nir_isub(b, lowered, |
| nir_iand(b, nir_ushr(b, lowered, c1), c55555555)); |
| |
| lowered = nir_iadd(b, |
| nir_iand(b, lowered, c33333333), |
| nir_iand(b, nir_ushr(b, lowered, c2), c33333333)); |
| |
| lowered = nir_ushr(b, |
| nir_imul(b, |
| nir_iand(b, |
| nir_iadd(b, |
| lowered, |
| nir_ushr(b, lowered, c4)), |
| c0f0f0f0f), |
| c01010101), |
| cshift); |
| |
| lowered = nir_u2u32(b, lowered); |
| } |
| break; |
| |
| case nir_op_imul_high: |
| case nir_op_umul_high: |
| if (b->shader->options->lower_mul_high) { |
| nir_def *src0 = nir_ssa_for_alu_src(b, instr, 0); |
| nir_def *src1 = nir_ssa_for_alu_src(b, instr, 1); |
| if (src0->bit_size < 32) { |
| /* Just do the math in 32-bit space and shift the result */ |
| nir_alu_type base_type = nir_op_infos[instr->op].output_type; |
| |
| nir_def *src0_32 = nir_type_convert(b, src0, base_type, base_type | 32, nir_rounding_mode_undef); |
| nir_def *src1_32 = nir_type_convert(b, src1, base_type, base_type | 32, nir_rounding_mode_undef); |
| nir_def *dest_32 = nir_imul(b, src0_32, src1_32); |
| nir_def *dest_shifted = nir_ishr_imm(b, dest_32, src0->bit_size); |
| lowered = nir_type_convert(b, dest_shifted, base_type, base_type | src0->bit_size, nir_rounding_mode_undef); |
| } else { |
| nir_def *cshift = nir_imm_int(b, src0->bit_size / 2); |
| nir_def *cmask = nir_imm_intN_t(b, (1ull << (src0->bit_size / 2)) - 1, src0->bit_size); |
| nir_def *different_signs = NULL; |
| if (instr->op == nir_op_imul_high) { |
| nir_def *c0 = nir_imm_intN_t(b, 0, src0->bit_size); |
| different_signs = nir_ixor(b, |
| nir_ilt(b, src0, c0), |
| nir_ilt(b, src1, c0)); |
| src0 = nir_iabs(b, src0); |
| src1 = nir_iabs(b, src1); |
| } |
| |
| /* ABCD |
| * * EFGH |
| * ====== |
| * (GH * CD) + (GH * AB) << 16 + (EF * CD) << 16 + (EF * AB) << 32 |
| * |
| * Start by splitting into the 4 multiplies. |
| */ |
| nir_def *src0l = nir_iand(b, src0, cmask); |
| nir_def *src1l = nir_iand(b, src1, cmask); |
| nir_def *src0h = nir_ushr(b, src0, cshift); |
| nir_def *src1h = nir_ushr(b, src1, cshift); |
| |
| nir_def *lo = nir_imul(b, src0l, src1l); |
| nir_def *m1 = nir_imul(b, src0l, src1h); |
| nir_def *m2 = nir_imul(b, src0h, src1l); |
| nir_def *hi = nir_imul(b, src0h, src1h); |
| |
| nir_def *tmp; |
| |
| tmp = nir_ishl(b, m1, cshift); |
| hi = nir_iadd(b, hi, nir_uadd_carry(b, lo, tmp)); |
| lo = nir_iadd(b, lo, tmp); |
| hi = nir_iadd(b, hi, nir_ushr(b, m1, cshift)); |
| |
| tmp = nir_ishl(b, m2, cshift); |
| hi = nir_iadd(b, hi, nir_uadd_carry(b, lo, tmp)); |
| lo = nir_iadd(b, lo, tmp); |
| hi = nir_iadd(b, hi, nir_ushr(b, m2, cshift)); |
| |
| if (instr->op == nir_op_imul_high) { |
| /* For channels where different_signs is set we have to perform a |
| * 64-bit negation. This is *not* the same as just negating the |
| * high 32-bits. Consider -3 * 2. The high 32-bits is 0, but the |
| * desired result is -1, not -0! Recall -x == ~x + 1. |
| */ |
| nir_def *c1 = nir_imm_intN_t(b, 1, src0->bit_size); |
| hi = nir_bcsel(b, different_signs, |
| nir_iadd(b, |
| nir_inot(b, hi), |
| nir_uadd_carry(b, nir_inot(b, lo), c1)), |
| hi); |
| } |
| |
| lowered = hi; |
| } |
| } |
| break; |
| |
| case nir_op_fmin: |
| case nir_op_fmax: { |
| if (!b->shader->options->lower_fminmax_signed_zero || |
| !nir_alu_instr_is_signed_zero_preserve(instr)) |
| break; |
| |
| nir_def *s0 = nir_ssa_for_alu_src(b, instr, 0); |
| nir_def *s1 = nir_ssa_for_alu_src(b, instr, 1); |
| |
| bool max = instr->op == nir_op_fmax; |
| nir_def *iminmax = max ? nir_imax(b, s0, s1) : nir_imin(b, s0, s1); |
| |
| /* Lower the fmin/fmax to a no_signed_zero fmin/fmax. This ensures that |
| * nir_lower_alu is idempotent, and allows the backend to implement |
| * soundly the no_signed_zero subset of fmin/fmax. |
| */ |
| b->fp_fast_math &= ~FLOAT_CONTROLS_SIGNED_ZERO_PRESERVE; |
| nir_def *fminmax = max ? nir_fmax(b, s0, s1) : nir_fmin(b, s0, s1); |
| b->fp_fast_math = instr->fp_fast_math; |
| |
| lowered = nir_bcsel(b, nir_feq(b, s0, s1), iminmax, fminmax); |
| break; |
| } |
| |
| default: |
| break; |
| } |
| |
| if (lowered) { |
| nir_def_replace(&instr->def, lowered); |
| return true; |
| } else { |
| return false; |
| } |
| } |
| |
| bool |
| nir_lower_alu(nir_shader *shader) |
| { |
| if (!shader->options->lower_bitfield_reverse && |
| !shader->options->lower_bit_count && |
| !shader->options->lower_mul_high && |
| !shader->options->lower_fminmax_signed_zero) |
| return false; |
| |
| return nir_shader_alu_pass(shader, lower_alu_instr, |
| nir_metadata_control_flow, NULL); |
| } |
