[Mesa-dev] [PATCH 01/38] i965/fs: Introduce FS IR builder.
Francisco Jerez
currojerez at riseup.net
Fri Jun 5 13:43:23 PDT 2015
Jordan Justen <jordan.l.justen at intel.com> writes:
> I guess we'll be carrying forward our strained backronym of FS as fast
> scalar? :)
>
Heh, of course :).
> -Jordan
>
> On 2015-06-04 09:04:50, Francisco Jerez wrote:
>> The purpose of this change is threefold: First, it improves the
>> modularity of the compiler back-end by separating the functionality
>> required to construct an i965 IR program from the rest of the visitor
>> god-object, what in turn will reduce the coupling between other
>> components and the visitor allowing a more modular design. This patch
>> doesn't yet remove the equivalent functionality from the visitor
>> classes, that task will be undertaken by a separate series, as it
>> involves major back-end surgery.
>>
>> Second, it improves consistency between the scalar and vector
>> back-ends. The FS and VEC4 builders can both be used to generate
>> scalar code with a compatible interface or they can be used to
>> generate natural vector width code -- 1 or 4 components respectively.
>>
>> Third, the approach to IR construction is somewhat different to what
>> the visitor classes currently do. All parameters affecting code
>> generation (execution size, half control, point in the program where
>> new instructions are inserted, etc.) are encapsulated in a stand-alone
>> object rather than being quasi-global state (yes, anything defined in
>> one of the visitor classes is effectively global due to the tight
>> coupling with virtually everything else in the compiler back-end).
>> This object is lightweight and can be copied, mutated and passed
>> around, making helper IR-building functions more flexible because they
>> can now simply take a builder object as argument and will inherit its
>> IR generation properties in exactly the same way that a discrete
>> instruction would from the same builder object.
>>
>> The emit_typed_write() function from my image-load-store branch is an
>> example that illustrates the usefulness of the latter point: Due to
>> hardware limitations the function may have to split the untyped
>> surface message in 8-wide chunks. That means that the several
>> functions called to help with the construction of the message payload
>> are themselves required to set the execution width and half control
>> correctly on the instructions they emit, and to allocate all registers
>> with half the default width. With the previous approach this would
>> require the used helper functions to be aware of the parameters that
>> might differ from the default state and explicitly set the instruction
>> bits accordingly. With the new approach they would get a modified
>> builder object as argument that would influence all instructions
>> emitted by the helper function as if it were the default state.
>>
>> Another example is the fs_visitor::VARYING_PULL_CONSTANT_LOAD()
>> method. It doesn't actually emit any instructions, they are simply
>> created and inserted into an exec_list which is returned for the
>> caller to emit at some location of the program. This sort of two-step
>> emission becomes unnecessary with the builder interface because the
>> insertion point is one more of the code generation parameters which
>> are part of the builder object. The caller can simply pass
>> VARYING_PULL_CONSTANT_LOAD() a modified builder object pointing at the
>> location of the program where the effect of the constant load is
>> desired. This two-step emission (which pervades the compiler back-end
>> and is in most cases redundant) goes away: E.g. ADD() now actually
>> adds two registers rather than just creating an ADD instruction in
>> memory, emit(ADD()) is no longer necessary.
>>
>> v2: Drop scalarizing VEC4 builder.
>> v3: Take a backend_shader as constructor argument. Improve handling
>> of debug annotations and execution control flags.
>> ---
>> src/mesa/drivers/dri/i965/Makefile.sources | 1 +
>> src/mesa/drivers/dri/i965/brw_fs_builder.h | 659 +++++++++++++++++++++++++++++
>> 2 files changed, 660 insertions(+)
>> create mode 100644 src/mesa/drivers/dri/i965/brw_fs_builder.h
>>
>> diff --git a/src/mesa/drivers/dri/i965/Makefile.sources b/src/mesa/drivers/dri/i965/Makefile.sources
>> index 3f852cd..93f336e 100644
>> --- a/src/mesa/drivers/dri/i965/Makefile.sources
>> +++ b/src/mesa/drivers/dri/i965/Makefile.sources
>> @@ -42,6 +42,7 @@ i965_FILES = \
>> brw_ff_gs.c \
>> brw_ff_gs_emit.c \
>> brw_ff_gs.h \
>> + brw_fs_builder.h \
>> brw_fs_channel_expressions.cpp \
>> brw_fs_cmod_propagation.cpp \
>> brw_fs_combine_constants.cpp \
>> diff --git a/src/mesa/drivers/dri/i965/brw_fs_builder.h b/src/mesa/drivers/dri/i965/brw_fs_builder.h
>> new file mode 100644
>> index 0000000..e528180
>> --- /dev/null
>> +++ b/src/mesa/drivers/dri/i965/brw_fs_builder.h
>> @@ -0,0 +1,659 @@
>> +/* -*- c++ -*- */
>> +/*
>> + * Copyright © 2010-2015 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.
>> + */
>> +
>> +#ifndef BRW_FS_BUILDER_H
>> +#define BRW_FS_BUILDER_H
>> +
>> +#include "brw_ir_fs.h"
>> +#include "brw_shader.h"
>> +#include "brw_context.h"
>> +
>> +namespace brw {
>> + /**
>> + * Toolbox to assemble an FS IR program out of individual instructions.
>> + *
>> + * This object is meant to have an interface consistent with
>> + * brw::vec4_builder. They cannot be fully interchangeable because
>> + * brw::fs_builder generates scalar code while brw::vec4_builder generates
>> + * vector code.
>> + */
>> + class fs_builder {
>> + public:
>> + /** Type used in this IR to represent a source of an instruction. */
>> + typedef fs_reg src_reg;
>> +
>> + /** Type used in this IR to represent the destination of an instruction. */
>> + typedef fs_reg dst_reg;
>> +
>> + /** Type used in this IR to represent an instruction. */
>> + typedef fs_inst instruction;
>> +
>> + /**
>> + * Construct an fs_builder appending instructions at the end of
>> + * the instruction list of \p shader. \p dispatch_width gives
>> + * the native execution width of the program.
>> + */
>> + fs_builder(backend_shader *shader,
>> + unsigned dispatch_width) :
>> + shader(shader), block(NULL),
>> + cursor((exec_node *)&shader->instructions.tail),
>> + _dispatch_width(dispatch_width),
>> + _group(0),
>> + force_writemask_all(false),
>> + annotation()
>> + {
>> + }
>> +
>> + /**
>> + * Construct an fs_builder that inserts instructions before \p cursor in
>> + * basic block \p block, inheriting other code generation parameters
>> + * from this.
>> + */
>> + fs_builder
>> + at(bblock_t *block, exec_node *cursor) const
>> + {
>> + fs_builder bld = *this;
>> + bld.block = block;
>> + bld.cursor = cursor;
>> + return bld;
>> + }
>> +
>> + /**
>> + * Construct a builder specifying the default SIMD width and group of
>> + * channel enable signals, inheriting other code generation parameters
>> + * from this.
>> + *
>> + * \p n gives the default SIMD width, \p i gives the slot group used for
>> + * predication and control flow masking in multiples of \p n channels.
>> + */
>> + fs_builder
>> + group(unsigned n, unsigned i) const
>> + {
>> + assert(n <= dispatch_width() &&
>> + i < dispatch_width() / n);
>> + fs_builder bld = *this;
>> + bld._dispatch_width = n;
>> + bld._group += i * n;
>> + return bld;
>> + }
>> +
>> + /**
>> + * Alias for group() with width equal to eight.
>> + */
>> + fs_builder
>> + half(unsigned i) const
>> + {
>> + return group(8, i);
>> + }
>> +
>> + /**
>> + * Construct a builder with per-channel control flow execution masking
>> + * disabled if \p b is true. If control flow execution masking is
>> + * already disabled this has no effect.
>> + */
>> + fs_builder
>> + exec_all(bool b = true) const
>> + {
>> + fs_builder bld = *this;
>> + if (b)
>> + bld.force_writemask_all = true;
>> + return bld;
>> + }
>> +
>> + /**
>> + * Construct a builder with the given debug annotation info.
>> + */
>> + fs_builder
>> + annotate(const char *str, const void *ir = NULL) const
>> + {
>> + fs_builder bld = *this;
>> + bld.annotation.str = str;
>> + bld.annotation.ir = ir;
>> + return bld;
>> + }
>> +
>> + /**
>> + * Get the SIMD width in use.
>> + */
>> + unsigned
>> + dispatch_width() const
>> + {
>> + return _dispatch_width;
>> + }
>> +
>> + /**
>> + * Allocate a virtual register of natural vector size (one for this IR)
>> + * and SIMD width. \p n gives the amount of space to allocate in
>> + * dispatch_width units (which is just enough space for one logical
>> + * component in this IR).
>> + */
>> + dst_reg
>> + vgrf(enum brw_reg_type type, unsigned n = 1) const
>> + {
>> + return dst_reg(GRF, shader->alloc.allocate(
>> + DIV_ROUND_UP(n * type_sz(type) * dispatch_width(),
>> + REG_SIZE)),
>> + type, dispatch_width());
>> + }
>> +
>> + /**
>> + * Create a null register of floating type.
>> + */
>> + dst_reg
>> + null_reg_f() const
>> + {
>> + return dst_reg(retype(brw_null_vec(dispatch_width()),
>> + BRW_REGISTER_TYPE_F));
>> + }
>> +
>> + /**
>> + * Create a null register of signed integer type.
>> + */
>> + dst_reg
>> + null_reg_d() const
>> + {
>> + return dst_reg(retype(brw_null_vec(dispatch_width()),
>> + BRW_REGISTER_TYPE_D));
>> + }
>> +
>> + /**
>> + * Create a null register of unsigned integer type.
>> + */
>> + dst_reg
>> + null_reg_ud() const
>> + {
>> + return dst_reg(retype(brw_null_vec(dispatch_width()),
>> + BRW_REGISTER_TYPE_UD));
>> + }
>> +
>> + /**
>> + * Get the mask of SIMD channels enabled by dispatch and not yet
>> + * disabled by discard.
>> + */
>> + src_reg
>> + sample_mask_reg() const
>> + {
>> + const bool uses_kill =
>> + (shader->stage == MESA_SHADER_FRAGMENT &&
>> + ((brw_wm_prog_data *)shader->stage_prog_data)->uses_kill);
>> + return (shader->stage != MESA_SHADER_FRAGMENT ? src_reg(0xffff) :
>> + uses_kill ? brw_flag_reg(0, 1) :
>> + retype(brw_vec1_grf(1, 7), BRW_REGISTER_TYPE_UD));
>> + }
>> +
>> + /**
>> + * Insert an instruction into the program.
>> + */
>> + instruction *
>> + emit(const instruction &inst) const
>> + {
>> + return emit(new(shader->mem_ctx) instruction(inst));
>> + }
>> +
>> + /**
>> + * Create and insert a nullary control instruction into the program.
>> + */
>> + instruction *
>> + emit(enum opcode opcode) const
>> + {
>> + return emit(instruction(opcode, dispatch_width()));
>> + }
>> +
>> + /**
>> + * Create and insert a nullary instruction into the program.
>> + */
>> + instruction *
>> + emit(enum opcode opcode, const dst_reg &dst) const
>> + {
>> + return emit(instruction(opcode, dst));
>> + }
>> +
>> + /**
>> + * Create and insert a unary instruction into the program.
>> + */
>> + instruction *
>> + emit(enum opcode opcode, const dst_reg &dst, const src_reg &src0) const
>> + {
>> + switch (opcode) {
>> + case SHADER_OPCODE_RCP:
>> + case SHADER_OPCODE_RSQ:
>> + case SHADER_OPCODE_SQRT:
>> + case SHADER_OPCODE_EXP2:
>> + case SHADER_OPCODE_LOG2:
>> + case SHADER_OPCODE_SIN:
>> + case SHADER_OPCODE_COS:
>> + return fix_math_instruction(
>> + emit(instruction(opcode, dst.width, dst,
>> + fix_math_operand(src0))));
>> +
>> + default:
>> + return emit(instruction(opcode, dst.width, dst, src0));
>> + }
>> + }
>> +
>> + /**
>> + * Create and insert a binary instruction into the program.
>> + */
>> + instruction *
>> + emit(enum opcode opcode, const dst_reg &dst, const src_reg &src0,
>> + const src_reg &src1) const
>> + {
>> + switch (opcode) {
>> + case SHADER_OPCODE_POW:
>> + case SHADER_OPCODE_INT_QUOTIENT:
>> + case SHADER_OPCODE_INT_REMAINDER:
>> + return fix_math_instruction(
>> + emit(instruction(opcode, dst.width, dst,
>> + fix_math_operand(src0),
>> + fix_math_operand(src1))));
>> +
>> + default:
>> + return emit(instruction(opcode, dst.width, dst, src0, src1));
>> +
>> + }
>> + }
>> +
>> + /**
>> + * Create and insert a ternary instruction into the program.
>> + */
>> + instruction *
>> + emit(enum opcode opcode, const dst_reg &dst, const src_reg &src0,
>> + const src_reg &src1, const src_reg &src2) const
>> + {
>> + switch (opcode) {
>> + case BRW_OPCODE_BFE:
>> + case BRW_OPCODE_BFI2:
>> + case BRW_OPCODE_MAD:
>> + case BRW_OPCODE_LRP:
>> + return emit(instruction(opcode, dst.width, dst,
>> + fix_3src_operand(src0),
>> + fix_3src_operand(src1),
>> + fix_3src_operand(src2)));
>> +
>> + default:
>> + return emit(instruction(opcode, dst.width, dst, src0, src1, src2));
>> + }
>> + }
>> +
>> + /**
>> + * Insert a preallocated instruction into the program.
>> + */
>> + instruction *
>> + emit(instruction *inst) const
>> + {
>> + assert(inst->exec_size == dispatch_width() ||
>> + force_writemask_all);
>> + assert(_group == 0 || _group == 8);
>> +
>> + inst->force_sechalf = (_group == 8);
>> + inst->force_writemask_all = force_writemask_all;
>> + inst->annotation = annotation.str;
>> + inst->ir = annotation.ir;
>> +
>> + if (block)
>> + static_cast<instruction *>(cursor)->insert_before(block, inst);
>> + else
>> + cursor->insert_before(inst);
>> +
>> + return inst;
>> + }
>> +
>> + /**
>> + * Select \p src0 if the comparison of both sources with the given
>> + * conditional mod evaluates to true, otherwise select \p src1.
>> + *
>> + * Generally useful to get the minimum or maximum of two values.
>> + */
>> + void
>> + emit_minmax(const dst_reg &dst, const src_reg &src0,
>> + const src_reg &src1, brw_conditional_mod mod) const
>> + {
>> + if (shader->devinfo->gen >= 6) {
>> + set_condmod(mod, SEL(dst, fix_unsigned_negate(src0),
>> + fix_unsigned_negate(src1)));
>> + } else {
>> + CMP(null_reg_d(), src0, src1, mod);
>> + set_predicate(BRW_PREDICATE_NORMAL,
>> + SEL(dst, src0, src1));
>> + }
>> + }
>> +
>> + /**
>> + * Copy any live channel from \p src to the first channel of \p dst.
>> + */
>> + void
>> + emit_uniformize(const dst_reg &dst, const src_reg &src) const
>> + {
>> + const fs_builder ubld = exec_all();
>> + const dst_reg chan_index = vgrf(BRW_REGISTER_TYPE_UD);
>> +
>> + ubld.emit(SHADER_OPCODE_FIND_LIVE_CHANNEL, component(chan_index, 0));
>> + ubld.emit(SHADER_OPCODE_BROADCAST, component(dst, 0),
>> + src, component(chan_index, 0));
>> + }
>> +
>> + /**
>> + * Assorted arithmetic ops.
>> + * @{
>> + */
>> +#define ALU1(op) \
>> + instruction * \
>> + op(const dst_reg &dst, const src_reg &src0) const \
>> + { \
>> + return emit(BRW_OPCODE_##op, dst, src0); \
>> + }
>> +
>> +#define ALU2(op) \
>> + instruction * \
>> + op(const dst_reg &dst, const src_reg &src0, const src_reg &src1) const \
>> + { \
>> + return emit(BRW_OPCODE_##op, dst, src0, src1); \
>> + }
>> +
>> +#define ALU2_ACC(op) \
>> + instruction * \
>> + op(const dst_reg &dst, const src_reg &src0, const src_reg &src1) const \
>> + { \
>> + instruction *inst = emit(BRW_OPCODE_##op, dst, src0, src1); \
>> + inst->writes_accumulator = true; \
>> + return inst; \
>> + }
>> +
>> +#define ALU3(op) \
>> + instruction * \
>> + op(const dst_reg &dst, const src_reg &src0, const src_reg &src1, \
>> + const src_reg &src2) const \
>> + { \
>> + return emit(BRW_OPCODE_##op, dst, src0, src1, src2); \
>> + }
>> +
>> + ALU2(ADD)
>> + ALU2_ACC(ADDC)
>> + ALU2(AND)
>> + ALU2(ASR)
>> + ALU2(AVG)
>> + ALU3(BFE)
>> + ALU2(BFI1)
>> + ALU3(BFI2)
>> + ALU1(BFREV)
>> + ALU1(CBIT)
>> + ALU2(CMPN)
>> + ALU3(CSEL)
>> + ALU2(DP2)
>> + ALU2(DP3)
>> + ALU2(DP4)
>> + ALU2(DPH)
>> + ALU1(F16TO32)
>> + ALU1(F32TO16)
>> + ALU1(FBH)
>> + ALU1(FBL)
>> + ALU1(FRC)
>> + ALU2(LINE)
>> + ALU1(LZD)
>> + ALU2(MAC)
>> + ALU2_ACC(MACH)
>> + ALU3(MAD)
>> + ALU1(MOV)
>> + ALU2(MUL)
>> + ALU1(NOT)
>> + ALU2(OR)
>> + ALU2(PLN)
>> + ALU1(RNDD)
>> + ALU1(RNDE)
>> + ALU1(RNDU)
>> + ALU1(RNDZ)
>> + ALU2(SAD2)
>> + ALU2_ACC(SADA2)
>> + ALU2(SEL)
>> + ALU2(SHL)
>> + ALU2(SHR)
>> + ALU2_ACC(SUBB)
>> + ALU2(XOR)
>> +
>> +#undef ALU3
>> +#undef ALU2_ACC
>> +#undef ALU2
>> +#undef ALU1
>> + /** @} */
>> +
>> + /**
>> + * CMP: Sets the low bit of the destination channels with the result
>> + * of the comparison, while the upper bits are undefined, and updates
>> + * the flag register with the packed 16 bits of the result.
>> + */
>> + instruction *
>> + CMP(const dst_reg &dst, const src_reg &src0, const src_reg &src1,
>> + brw_conditional_mod condition) const
>> + {
>> + /* Take the instruction:
>> + *
>> + * CMP null<d> src0<f> src1<f>
>> + *
>> + * Original gen4 does type conversion to the destination type
>> + * before comparison, producing garbage results for floating
>> + * point comparisons.
>> + *
>> + * The destination type doesn't matter on newer generations,
>> + * so we set the type to match src0 so we can compact the
>> + * instruction.
>> + */
>> + return set_condmod(condition,
>> + emit(BRW_OPCODE_CMP, retype(dst, src0.type),
>> + fix_unsigned_negate(src0),
>> + fix_unsigned_negate(src1)));
>> + }
>> +
>> + /**
>> + * Gen4 predicated IF.
>> + */
>> + instruction *
>> + IF(brw_predicate predicate) const
>> + {
>> + instruction *inst = emit(BRW_OPCODE_IF);
>> + return set_predicate(predicate, inst);
>> + }
>> +
>> + /**
>> + * Gen6 IF with embedded comparison.
>> + */
>> + instruction *
>> + IF(const src_reg &src0, const src_reg &src1,
>> + brw_conditional_mod condition) const
>> + {
>> + assert(shader->devinfo->gen == 6);
>> + return set_condmod(condition,
>> + emit(BRW_OPCODE_IF,
>> + null_reg_d(),
>> + fix_unsigned_negate(src0),
>> + fix_unsigned_negate(src1)));
>> + }
>> +
>> + /**
>> + * Emit a linear interpolation instruction.
>> + */
>> + instruction *
>> + LRP(const dst_reg &dst, const src_reg &x, const src_reg &y,
>> + const src_reg &a) const
>> + {
>> + if (shader->devinfo->gen >= 6) {
>> + /* The LRP instruction actually does op1 * op0 + op2 * (1 - op0), so
>> + * we need to reorder the operands.
>> + */
>> + return emit(BRW_OPCODE_LRP, dst, a, y, x);
>> +
>> + } else {
>> + /* We can't use the LRP instruction. Emit x*(1-a) + y*a. */
>> + const dst_reg y_times_a = vgrf(dst.type);
>> + const dst_reg one_minus_a = vgrf(dst.type);
>> + const dst_reg x_times_one_minus_a = vgrf(dst.type);
>> +
>> + MUL(y_times_a, y, a);
>> + ADD(one_minus_a, negate(a), src_reg(1.0f));
>> + MUL(x_times_one_minus_a, x, src_reg(one_minus_a));
>> + return ADD(dst, src_reg(x_times_one_minus_a), src_reg(y_times_a));
>> + }
>> + }
>> +
>> + /**
>> + * Collect a number of registers in a contiguous range of registers.
>> + */
>> + instruction *
>> + LOAD_PAYLOAD(const dst_reg &dst, const src_reg *src,
>> + unsigned sources, unsigned header_size) const
>> + {
>> + assert(dst.width % 8 == 0);
>> + instruction *inst = emit(instruction(SHADER_OPCODE_LOAD_PAYLOAD,
>> + dst.width, dst, src, sources));
>> + inst->header_size = header_size;
>> +
>> + for (unsigned i = 0; i < header_size; i++)
>> + assert(src[i].file != GRF ||
>> + src[i].width * type_sz(src[i].type) == 32);
>> + inst->regs_written = header_size;
>> +
>> + for (unsigned i = header_size; i < sources; ++i)
>> + assert(src[i].file != GRF ||
>> + src[i].width == dst.width);
>> + inst->regs_written += (sources - header_size) * (dst.width / 8);
>> +
>> + return inst;
>> + }
>> +
>> + backend_shader *shader;
>> +
>> + private:
>> + /**
>> + * Workaround for negation of UD registers. See comment in
>> + * fs_generator::generate_code() for more details.
>> + */
>> + src_reg
>> + fix_unsigned_negate(const src_reg &src) const
>> + {
>> + if (src.type == BRW_REGISTER_TYPE_UD &&
>> + src.negate) {
>> + dst_reg temp = vgrf(BRW_REGISTER_TYPE_UD);
>> + MOV(temp, src);
>> + return src_reg(temp);
>> + } else {
>> + return src;
>> + }
>> + }
>> +
>> + /**
>> + * Workaround for source register modes not supported by the ternary
>> + * instruction encoding.
>> + */
>> + src_reg
>> + fix_3src_operand(const src_reg &src) const
>> + {
>> + if (src.file == GRF || src.file == UNIFORM || src.stride > 1) {
>> + return src;
>> + } else {
>> + dst_reg expanded = vgrf(src.type);
>> + MOV(expanded, src);
>> + return expanded;
>> + }
>> + }
>> +
>> + /**
>> + * Workaround for source register modes not supported by the math
>> + * instruction.
>> + */
>> + src_reg
>> + fix_math_operand(const src_reg &src) const
>> + {
>> + /* Can't do hstride == 0 args on gen6 math, so expand it out. We
>> + * might be able to do better by doing execsize = 1 math and then
>> + * expanding that result out, but we would need to be careful with
>> + * masking.
>> + *
>> + * Gen6 hardware ignores source modifiers (negate and abs) on math
>> + * instructions, so we also move to a temp to set those up.
>> + *
>> + * Gen7 relaxes most of the above restrictions, but still can't use IMM
>> + * operands to math
>> + */
>> + if ((shader->devinfo->gen == 6 &&
>> + (src.file == IMM || src.file == UNIFORM ||
>> + src.abs || src.negate)) ||
>> + (shader->devinfo->gen == 7 && src.file == IMM)) {
>> + const dst_reg tmp = vgrf(src.type);
>> + MOV(tmp, src);
>> + return tmp;
>> + } else {
>> + return src;
>> + }
>> + }
>> +
>> + /**
>> + * Workaround other weirdness of the math instruction.
>> + */
>> + instruction *
>> + fix_math_instruction(instruction *instr) const
>> + {
>> + if (shader->devinfo->gen < 6) {
>> + instr->base_mrf = 2;
>> + instr->mlen = instr->sources * dispatch_width() / 8;
>> +
>> + if (instr->sources > 1) {
>> + /* From the Ironlake PRM, Volume 4, Part 1, Section 6.1.13
>> + * "Message Payload":
>> + *
>> + * "Operand0[7]. For the INT DIV functions, this operand is the
>> + * denominator."
>> + * ...
>> + * "Operand1[7]. For the INT DIV functions, this operand is the
>> + * numerator."
>> + */
>> + const bool is_int_div = instr->opcode != SHADER_OPCODE_POW;
>> + const fs_reg src0 = is_int_div ? instr->src[1] : instr->src[0];
>> + const fs_reg src1 = is_int_div ? instr->src[0] : instr->src[1];
>> +
>> + instr->resize_sources(1);
>> + instr->src[0] = src0;
>> +
>> + at(block, instr).MOV(fs_reg(MRF, instr->base_mrf + 1, src1.type,
>> + dispatch_width()), src1);
>> + }
>> + }
>> +
>> + return instr;
>> + }
>> +
>> + bblock_t *block;
>> + exec_node *cursor;
>> +
>> + unsigned _dispatch_width;
>> + unsigned _group;
>> + bool force_writemask_all;
>> +
>> + /** Debug annotation info. */
>> + struct {
>> + const char *str;
>> + const void *ir;
>> + } annotation;
>> + };
>> +}
>> +
>> +#endif
>> --
>> 2.3.5
>>
>> _______________________________________________
>> mesa-dev mailing list
>> mesa-dev at lists.freedesktop.org
>> http://lists.freedesktop.org/mailman/listinfo/mesa-dev
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