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folding_rules.cpp
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// Copyright (c) 2018 Google LLC
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
#include "source/opt/folding_rules.h"
#include <limits>
#include <memory>
#include <utility>
#include "ir_builder.h"
#include "source/latest_version_glsl_std_450_header.h"
#include "source/opt/ir_context.h"
namespace spvtools {
namespace opt {
namespace {
constexpr uint32_t kExtractCompositeIdInIdx = 0;
constexpr uint32_t kInsertObjectIdInIdx = 0;
constexpr uint32_t kInsertCompositeIdInIdx = 1;
constexpr uint32_t kExtInstSetIdInIdx = 0;
constexpr uint32_t kExtInstInstructionInIdx = 1;
constexpr uint32_t kFMixXIdInIdx = 2;
constexpr uint32_t kFMixYIdInIdx = 3;
constexpr uint32_t kFMixAIdInIdx = 4;
constexpr uint32_t kStoreObjectInIdx = 1;
// Some image instructions may contain an "image operands" argument.
// Returns the operand index for the "image operands".
// Returns -1 if the instruction does not have image operands.
int32_t ImageOperandsMaskInOperandIndex(Instruction* inst) {
const auto opcode = inst->opcode();
switch (opcode) {
case spv::Op::OpImageSampleImplicitLod:
case spv::Op::OpImageSampleExplicitLod:
case spv::Op::OpImageSampleProjImplicitLod:
case spv::Op::OpImageSampleProjExplicitLod:
case spv::Op::OpImageFetch:
case spv::Op::OpImageRead:
case spv::Op::OpImageSparseSampleImplicitLod:
case spv::Op::OpImageSparseSampleExplicitLod:
case spv::Op::OpImageSparseSampleProjImplicitLod:
case spv::Op::OpImageSparseSampleProjExplicitLod:
case spv::Op::OpImageSparseFetch:
case spv::Op::OpImageSparseRead:
return inst->NumOperands() > 4 ? 2 : -1;
case spv::Op::OpImageSampleDrefImplicitLod:
case spv::Op::OpImageSampleDrefExplicitLod:
case spv::Op::OpImageSampleProjDrefImplicitLod:
case spv::Op::OpImageSampleProjDrefExplicitLod:
case spv::Op::OpImageGather:
case spv::Op::OpImageDrefGather:
case spv::Op::OpImageSparseSampleDrefImplicitLod:
case spv::Op::OpImageSparseSampleDrefExplicitLod:
case spv::Op::OpImageSparseSampleProjDrefImplicitLod:
case spv::Op::OpImageSparseSampleProjDrefExplicitLod:
case spv::Op::OpImageSparseGather:
case spv::Op::OpImageSparseDrefGather:
return inst->NumOperands() > 5 ? 3 : -1;
case spv::Op::OpImageWrite:
return inst->NumOperands() > 3 ? 3 : -1;
default:
return -1;
}
}
// Returns the element width of |type|.
uint32_t ElementWidth(const analysis::Type* type) {
if (const analysis::Vector* vec_type = type->AsVector()) {
return ElementWidth(vec_type->element_type());
} else if (const analysis::Float* float_type = type->AsFloat()) {
return float_type->width();
} else {
assert(type->AsInteger());
return type->AsInteger()->width();
}
}
// Returns true if |type| is Float or a vector of Float.
bool HasFloatingPoint(const analysis::Type* type) {
if (type->AsFloat()) {
return true;
} else if (const analysis::Vector* vec_type = type->AsVector()) {
return vec_type->element_type()->AsFloat() != nullptr;
}
return false;
}
// Returns false if |val| is NaN, infinite or subnormal.
template <typename T>
bool IsValidResult(T val) {
int classified = std::fpclassify(val);
switch (classified) {
case FP_NAN:
case FP_INFINITE:
case FP_SUBNORMAL:
return false;
default:
return true;
}
}
// Returns true if `type` is a cooperative matrix.
bool IsCooperativeMatrix(const analysis::Type* type) {
return type->kind() == analysis::Type::kCooperativeMatrixKHR ||
type->kind() == analysis::Type::kCooperativeMatrixNV;
}
const analysis::Constant* ConstInput(
const std::vector<const analysis::Constant*>& constants) {
return constants[0] ? constants[0] : constants[1];
}
Instruction* NonConstInput(IRContext* context, const analysis::Constant* c,
Instruction* inst) {
uint32_t in_op = c ? 1u : 0u;
return context->get_def_use_mgr()->GetDef(
inst->GetSingleWordInOperand(in_op));
}
std::vector<uint32_t> ExtractInts(uint64_t val) {
std::vector<uint32_t> words;
words.push_back(static_cast<uint32_t>(val));
words.push_back(static_cast<uint32_t>(val >> 32));
return words;
}
std::vector<uint32_t> GetWordsFromScalarIntConstant(
const analysis::IntConstant* c) {
assert(c != nullptr);
uint32_t width = c->type()->AsInteger()->width();
assert(width == 8 || width == 16 || width == 32 || width == 64);
if (width == 64) {
uint64_t uval = static_cast<uint64_t>(c->GetU64());
return ExtractInts(uval);
}
// Section 2.2.1 of the SPIR-V spec guarantees that all integer types
// smaller than 32-bits are automatically zero or sign extended to 32-bits.
return {c->GetU32BitValue()};
}
std::vector<uint32_t> GetWordsFromScalarFloatConstant(
const analysis::FloatConstant* c) {
assert(c != nullptr);
uint32_t width = c->type()->AsFloat()->width();
assert(width == 16 || width == 32 || width == 64);
if (width == 64) {
utils::FloatProxy<double> result(c->GetDouble());
return result.GetWords();
}
// Section 2.2.1 of the SPIR-V spec guarantees that all floating-point types
// smaller than 32-bits are automatically zero extended to 32-bits.
return {c->GetU32BitValue()};
}
std::vector<uint32_t> GetWordsFromNumericScalarOrVectorConstant(
analysis::ConstantManager* const_mgr, const analysis::Constant* c) {
if (const auto* float_constant = c->AsFloatConstant()) {
return GetWordsFromScalarFloatConstant(float_constant);
} else if (const auto* int_constant = c->AsIntConstant()) {
return GetWordsFromScalarIntConstant(int_constant);
} else if (const auto* vec_constant = c->AsVectorConstant()) {
std::vector<uint32_t> words;
for (const auto* comp : vec_constant->GetComponents()) {
auto comp_in_words =
GetWordsFromNumericScalarOrVectorConstant(const_mgr, comp);
words.insert(words.end(), comp_in_words.begin(), comp_in_words.end());
}
return words;
}
return {};
}
const analysis::Constant* ConvertWordsToNumericScalarOrVectorConstant(
analysis::ConstantManager* const_mgr, const std::vector<uint32_t>& words,
const analysis::Type* type) {
const spvtools::opt::analysis::Integer* int_type = type->AsInteger();
if (int_type && int_type->width() <= 32) {
assert(words.size() == 1);
return const_mgr->GenerateIntegerConstant(int_type, words[0]);
}
if (int_type || type->AsFloat()) return const_mgr->GetConstant(type, words);
if (const auto* vec_type = type->AsVector())
return const_mgr->GetNumericVectorConstantWithWords(vec_type, words);
return nullptr;
}
// Returns the negation of |c|. |c| must be a 32 or 64 bit floating point
// constant.
uint32_t NegateFloatingPointConstant(analysis::ConstantManager* const_mgr,
const analysis::Constant* c) {
assert(c);
assert(c->type()->AsFloat());
uint32_t width = c->type()->AsFloat()->width();
assert(width == 32 || width == 64);
std::vector<uint32_t> words;
if (width == 64) {
utils::FloatProxy<double> result(c->GetDouble() * -1.0);
words = result.GetWords();
} else {
utils::FloatProxy<float> result(c->GetFloat() * -1.0f);
words = result.GetWords();
}
const analysis::Constant* negated_const =
const_mgr->GetConstant(c->type(), std::move(words));
return const_mgr->GetDefiningInstruction(negated_const)->result_id();
}
// Negates the integer constant |c|. Returns the id of the defining instruction.
uint32_t NegateIntegerConstant(analysis::ConstantManager* const_mgr,
const analysis::Constant* c) {
assert(c);
assert(c->type()->AsInteger());
uint32_t width = c->type()->AsInteger()->width();
assert(width == 32 || width == 64);
std::vector<uint32_t> words;
if (width == 64) {
uint64_t uval = static_cast<uint64_t>(0 - c->GetU64());
words = ExtractInts(uval);
} else {
words.push_back(static_cast<uint32_t>(0 - c->GetU32()));
}
const analysis::Constant* negated_const =
const_mgr->GetConstant(c->type(), std::move(words));
return const_mgr->GetDefiningInstruction(negated_const)->result_id();
}
// Negates the vector constant |c|. Returns the id of the defining instruction.
uint32_t NegateVectorConstant(analysis::ConstantManager* const_mgr,
const analysis::Constant* c) {
assert(const_mgr && c);
assert(c->type()->AsVector());
if (c->AsNullConstant()) {
// 0.0 vs -0.0 shouldn't matter.
return const_mgr->GetDefiningInstruction(c)->result_id();
} else {
const analysis::Type* component_type =
c->AsVectorConstant()->component_type();
std::vector<uint32_t> words;
for (auto& comp : c->AsVectorConstant()->GetComponents()) {
if (component_type->AsFloat()) {
words.push_back(NegateFloatingPointConstant(const_mgr, comp));
} else {
assert(component_type->AsInteger());
words.push_back(NegateIntegerConstant(const_mgr, comp));
}
}
const analysis::Constant* negated_const =
const_mgr->GetConstant(c->type(), std::move(words));
return const_mgr->GetDefiningInstruction(negated_const)->result_id();
}
}
// Negates |c|. Returns the id of the defining instruction.
uint32_t NegateConstant(analysis::ConstantManager* const_mgr,
const analysis::Constant* c) {
if (c->type()->AsVector()) {
return NegateVectorConstant(const_mgr, c);
} else if (c->type()->AsFloat()) {
return NegateFloatingPointConstant(const_mgr, c);
} else {
assert(c->type()->AsInteger());
return NegateIntegerConstant(const_mgr, c);
}
}
// Takes the reciprocal of |c|. |c|'s type must be Float or a vector of Float.
// Returns 0 if the reciprocal is NaN, infinite or subnormal.
uint32_t Reciprocal(analysis::ConstantManager* const_mgr,
const analysis::Constant* c) {
assert(const_mgr && c);
assert(c->type()->AsFloat());
uint32_t width = c->type()->AsFloat()->width();
assert(width == 32 || width == 64);
std::vector<uint32_t> words;
if (c->IsZero()) {
return 0;
}
if (width == 64) {
spvtools::utils::FloatProxy<double> result(1.0 / c->GetDouble());
if (!IsValidResult(result.getAsFloat())) return 0;
words = result.GetWords();
} else {
spvtools::utils::FloatProxy<float> result(1.0f / c->GetFloat());
if (!IsValidResult(result.getAsFloat())) return 0;
words = result.GetWords();
}
const analysis::Constant* negated_const =
const_mgr->GetConstant(c->type(), std::move(words));
return const_mgr->GetDefiningInstruction(negated_const)->result_id();
}
// Replaces fdiv where second operand is constant with fmul.
FoldingRule ReciprocalFDiv() {
return [](IRContext* context, Instruction* inst,
const std::vector<const analysis::Constant*>& constants) {
assert(inst->opcode() == spv::Op::OpFDiv);
analysis::ConstantManager* const_mgr = context->get_constant_mgr();
const analysis::Type* type =
context->get_type_mgr()->GetType(inst->type_id());
if (IsCooperativeMatrix(type)) {
return false;
}
if (!inst->IsFloatingPointFoldingAllowed()) return false;
uint32_t width = ElementWidth(type);
if (width != 32 && width != 64) return false;
if (constants[1] != nullptr) {
uint32_t id = 0;
if (const analysis::VectorConstant* vector_const =
constants[1]->AsVectorConstant()) {
std::vector<uint32_t> neg_ids;
for (auto& comp : vector_const->GetComponents()) {
id = Reciprocal(const_mgr, comp);
if (id == 0) return false;
neg_ids.push_back(id);
}
const analysis::Constant* negated_const =
const_mgr->GetConstant(constants[1]->type(), std::move(neg_ids));
id = const_mgr->GetDefiningInstruction(negated_const)->result_id();
} else if (constants[1]->AsFloatConstant()) {
id = Reciprocal(const_mgr, constants[1]);
if (id == 0) return false;
} else {
// Don't fold a null constant.
return false;
}
inst->SetOpcode(spv::Op::OpFMul);
inst->SetInOperands(
{{SPV_OPERAND_TYPE_ID, {inst->GetSingleWordInOperand(0u)}},
{SPV_OPERAND_TYPE_ID, {id}}});
return true;
}
return false;
};
}
// Elides consecutive negate instructions.
FoldingRule MergeNegateArithmetic() {
return [](IRContext* context, Instruction* inst,
const std::vector<const analysis::Constant*>& constants) {
assert(inst->opcode() == spv::Op::OpFNegate ||
inst->opcode() == spv::Op::OpSNegate);
(void)constants;
const analysis::Type* type =
context->get_type_mgr()->GetType(inst->type_id());
if (HasFloatingPoint(type) && !inst->IsFloatingPointFoldingAllowed())
return false;
Instruction* op_inst =
context->get_def_use_mgr()->GetDef(inst->GetSingleWordInOperand(0u));
if (HasFloatingPoint(type) && !op_inst->IsFloatingPointFoldingAllowed())
return false;
if (op_inst->opcode() == inst->opcode()) {
// Elide negates.
inst->SetOpcode(spv::Op::OpCopyObject);
inst->SetInOperands(
{{SPV_OPERAND_TYPE_ID, {op_inst->GetSingleWordInOperand(0u)}}});
return true;
}
return false;
};
}
// Merges negate into a mul or div operation if that operation contains a
// constant operand.
// Cases:
// -(x * 2) = x * -2
// -(2 * x) = x * -2
// -(x / 2) = x / -2
// -(2 / x) = -2 / x
FoldingRule MergeNegateMulDivArithmetic() {
return [](IRContext* context, Instruction* inst,
const std::vector<const analysis::Constant*>& constants) {
assert(inst->opcode() == spv::Op::OpFNegate ||
inst->opcode() == spv::Op::OpSNegate);
(void)constants;
analysis::ConstantManager* const_mgr = context->get_constant_mgr();
const analysis::Type* type =
context->get_type_mgr()->GetType(inst->type_id());
if (IsCooperativeMatrix(type)) {
return false;
}
if (HasFloatingPoint(type) && !inst->IsFloatingPointFoldingAllowed())
return false;
Instruction* op_inst =
context->get_def_use_mgr()->GetDef(inst->GetSingleWordInOperand(0u));
if (HasFloatingPoint(type) && !op_inst->IsFloatingPointFoldingAllowed())
return false;
uint32_t width = ElementWidth(type);
if (width != 32 && width != 64) return false;
spv::Op opcode = op_inst->opcode();
if (opcode != spv::Op::OpFMul && opcode != spv::Op::OpFDiv &&
opcode != spv::Op::OpIMul && opcode != spv::Op::OpSDiv) {
return false;
}
std::vector<const analysis::Constant*> op_constants =
const_mgr->GetOperandConstants(op_inst);
// Merge negate into mul or div if one operand is constant.
if (op_constants[0] == nullptr && op_constants[1] == nullptr) {
return false;
}
bool zero_is_variable = op_constants[0] == nullptr;
const analysis::Constant* c = ConstInput(op_constants);
uint32_t neg_id = NegateConstant(const_mgr, c);
uint32_t non_const_id = zero_is_variable
? op_inst->GetSingleWordInOperand(0u)
: op_inst->GetSingleWordInOperand(1u);
// Change this instruction to a mul/div.
inst->SetOpcode(op_inst->opcode());
if (opcode == spv::Op::OpFDiv || opcode == spv::Op::OpUDiv ||
opcode == spv::Op::OpSDiv) {
uint32_t op0 = zero_is_variable ? non_const_id : neg_id;
uint32_t op1 = zero_is_variable ? neg_id : non_const_id;
inst->SetInOperands(
{{SPV_OPERAND_TYPE_ID, {op0}}, {SPV_OPERAND_TYPE_ID, {op1}}});
} else {
inst->SetInOperands({{SPV_OPERAND_TYPE_ID, {non_const_id}},
{SPV_OPERAND_TYPE_ID, {neg_id}}});
}
return true;
};
}
// Merges negate into a add or sub operation if that operation contains a
// constant operand.
// Cases:
// -(x + 2) = -2 - x
// -(2 + x) = -2 - x
// -(x - 2) = 2 - x
// -(2 - x) = x - 2
FoldingRule MergeNegateAddSubArithmetic() {
return [](IRContext* context, Instruction* inst,
const std::vector<const analysis::Constant*>& constants) {
assert(inst->opcode() == spv::Op::OpFNegate ||
inst->opcode() == spv::Op::OpSNegate);
(void)constants;
analysis::ConstantManager* const_mgr = context->get_constant_mgr();
const analysis::Type* type =
context->get_type_mgr()->GetType(inst->type_id());
if (IsCooperativeMatrix(type)) {
return false;
}
if (HasFloatingPoint(type) && !inst->IsFloatingPointFoldingAllowed())
return false;
Instruction* op_inst =
context->get_def_use_mgr()->GetDef(inst->GetSingleWordInOperand(0u));
if (HasFloatingPoint(type) && !op_inst->IsFloatingPointFoldingAllowed())
return false;
uint32_t width = ElementWidth(type);
if (width != 32 && width != 64) return false;
if (op_inst->opcode() == spv::Op::OpFAdd ||
op_inst->opcode() == spv::Op::OpFSub ||
op_inst->opcode() == spv::Op::OpIAdd ||
op_inst->opcode() == spv::Op::OpISub) {
std::vector<const analysis::Constant*> op_constants =
const_mgr->GetOperandConstants(op_inst);
if (op_constants[0] || op_constants[1]) {
bool zero_is_variable = op_constants[0] == nullptr;
bool is_add = (op_inst->opcode() == spv::Op::OpFAdd) ||
(op_inst->opcode() == spv::Op::OpIAdd);
bool swap_operands = !is_add || zero_is_variable;
bool negate_const = is_add;
const analysis::Constant* c = ConstInput(op_constants);
uint32_t const_id = 0;
if (negate_const) {
const_id = NegateConstant(const_mgr, c);
} else {
const_id = zero_is_variable ? op_inst->GetSingleWordInOperand(1u)
: op_inst->GetSingleWordInOperand(0u);
}
// Swap operands if necessary and make the instruction a subtraction.
uint32_t op0 =
zero_is_variable ? op_inst->GetSingleWordInOperand(0u) : const_id;
uint32_t op1 =
zero_is_variable ? const_id : op_inst->GetSingleWordInOperand(1u);
if (swap_operands) std::swap(op0, op1);
inst->SetOpcode(HasFloatingPoint(type) ? spv::Op::OpFSub
: spv::Op::OpISub);
inst->SetInOperands(
{{SPV_OPERAND_TYPE_ID, {op0}}, {SPV_OPERAND_TYPE_ID, {op1}}});
return true;
}
}
return false;
};
}
// Returns true if |c| has a zero element.
bool HasZero(const analysis::Constant* c) {
if (c->AsNullConstant()) {
return true;
}
if (const analysis::VectorConstant* vec_const = c->AsVectorConstant()) {
for (auto& comp : vec_const->GetComponents())
if (HasZero(comp)) return true;
} else {
assert(c->AsScalarConstant());
return c->AsScalarConstant()->IsZero();
}
return false;
}
// Performs |input1| |opcode| |input2| and returns the merged constant result
// id. Returns 0 if the result is not a valid value. The input types must be
// Float.
uint32_t PerformFloatingPointOperation(analysis::ConstantManager* const_mgr,
spv::Op opcode,
const analysis::Constant* input1,
const analysis::Constant* input2) {
const analysis::Type* type = input1->type();
assert(type->AsFloat());
uint32_t width = type->AsFloat()->width();
assert(width == 32 || width == 64);
std::vector<uint32_t> words;
#define FOLD_OP(op) \
if (width == 64) { \
utils::FloatProxy<double> val = \
input1->GetDouble() op input2->GetDouble(); \
double dval = val.getAsFloat(); \
if (!IsValidResult(dval)) return 0; \
words = val.GetWords(); \
} else { \
utils::FloatProxy<float> val = input1->GetFloat() op input2->GetFloat(); \
float fval = val.getAsFloat(); \
if (!IsValidResult(fval)) return 0; \
words = val.GetWords(); \
} \
static_assert(true, "require extra semicolon")
switch (opcode) {
case spv::Op::OpFMul:
FOLD_OP(*);
break;
case spv::Op::OpFDiv:
if (HasZero(input2)) return 0;
FOLD_OP(/);
break;
case spv::Op::OpFAdd:
FOLD_OP(+);
break;
case spv::Op::OpFSub:
FOLD_OP(-);
break;
default:
assert(false && "Unexpected operation");
break;
}
#undef FOLD_OP
const analysis::Constant* merged_const = const_mgr->GetConstant(type, words);
return const_mgr->GetDefiningInstruction(merged_const)->result_id();
}
// Performs |input1| |opcode| |input2| and returns the merged constant result
// id. Returns 0 if the result is not a valid value. The input types must be
// Integers.
uint32_t PerformIntegerOperation(analysis::ConstantManager* const_mgr,
spv::Op opcode,
const analysis::Constant* input1,
const analysis::Constant* input2) {
assert(input1->type()->AsInteger());
const analysis::Integer* type = input1->type()->AsInteger();
uint32_t width = type->AsInteger()->width();
assert(width == 32 || width == 64);
std::vector<uint32_t> words;
// Regardless of the sign of the constant, folding is performed on an unsigned
// interpretation of the constant data. This avoids signed integer overflow
// while folding, and works because sign is irrelevant for the IAdd, ISub and
// IMul instructions.
#define FOLD_OP(op) \
if (width == 64) { \
uint64_t val = input1->GetU64() op input2->GetU64(); \
words = ExtractInts(val); \
} else { \
uint32_t val = input1->GetU32() op input2->GetU32(); \
words.push_back(val); \
} \
static_assert(true, "require extra semicolon")
switch (opcode) {
case spv::Op::OpIMul:
FOLD_OP(*);
break;
case spv::Op::OpSDiv:
case spv::Op::OpUDiv:
assert(false && "Should not merge integer division");
break;
case spv::Op::OpIAdd:
FOLD_OP(+);
break;
case spv::Op::OpISub:
FOLD_OP(-);
break;
default:
assert(false && "Unexpected operation");
break;
}
#undef FOLD_OP
const analysis::Constant* merged_const = const_mgr->GetConstant(type, words);
return const_mgr->GetDefiningInstruction(merged_const)->result_id();
}
// Performs |input1| |opcode| |input2| and returns the merged constant result
// id. Returns 0 if the result is not a valid value. The input types must be
// Integers, Floats or Vectors of such.
uint32_t PerformOperation(analysis::ConstantManager* const_mgr, spv::Op opcode,
const analysis::Constant* input1,
const analysis::Constant* input2) {
assert(input1 && input2);
const analysis::Type* type = input1->type();
std::vector<uint32_t> words;
if (const analysis::Vector* vector_type = type->AsVector()) {
const analysis::Type* ele_type = vector_type->element_type();
for (uint32_t i = 0; i != vector_type->element_count(); ++i) {
uint32_t id = 0;
const analysis::Constant* input1_comp = nullptr;
if (const analysis::VectorConstant* input1_vector =
input1->AsVectorConstant()) {
input1_comp = input1_vector->GetComponents()[i];
} else {
assert(input1->AsNullConstant());
input1_comp = const_mgr->GetConstant(ele_type, {});
}
const analysis::Constant* input2_comp = nullptr;
if (const analysis::VectorConstant* input2_vector =
input2->AsVectorConstant()) {
input2_comp = input2_vector->GetComponents()[i];
} else {
assert(input2->AsNullConstant());
input2_comp = const_mgr->GetConstant(ele_type, {});
}
if (ele_type->AsFloat()) {
id = PerformFloatingPointOperation(const_mgr, opcode, input1_comp,
input2_comp);
} else {
assert(ele_type->AsInteger());
id = PerformIntegerOperation(const_mgr, opcode, input1_comp,
input2_comp);
}
if (id == 0) return 0;
words.push_back(id);
}
const analysis::Constant* merged_const =
const_mgr->GetConstant(type, words);
return const_mgr->GetDefiningInstruction(merged_const)->result_id();
} else if (type->AsFloat()) {
return PerformFloatingPointOperation(const_mgr, opcode, input1, input2);
} else {
assert(type->AsInteger());
return PerformIntegerOperation(const_mgr, opcode, input1, input2);
}
}
// Merges consecutive multiplies where each contains one constant operand.
// Cases:
// 2 * (x * 2) = x * 4
// 2 * (2 * x) = x * 4
// (x * 2) * 2 = x * 4
// (2 * x) * 2 = x * 4
FoldingRule MergeMulMulArithmetic() {
return [](IRContext* context, Instruction* inst,
const std::vector<const analysis::Constant*>& constants) {
assert(inst->opcode() == spv::Op::OpFMul ||
inst->opcode() == spv::Op::OpIMul);
analysis::ConstantManager* const_mgr = context->get_constant_mgr();
const analysis::Type* type =
context->get_type_mgr()->GetType(inst->type_id());
if (IsCooperativeMatrix(type)) {
return false;
}
if (HasFloatingPoint(type) && !inst->IsFloatingPointFoldingAllowed())
return false;
uint32_t width = ElementWidth(type);
if (width != 32 && width != 64) return false;
// Determine the constant input and the variable input in |inst|.
const analysis::Constant* const_input1 = ConstInput(constants);
if (!const_input1) return false;
Instruction* other_inst = NonConstInput(context, constants[0], inst);
if (HasFloatingPoint(type) && !other_inst->IsFloatingPointFoldingAllowed())
return false;
if (other_inst->opcode() == inst->opcode()) {
std::vector<const analysis::Constant*> other_constants =
const_mgr->GetOperandConstants(other_inst);
const analysis::Constant* const_input2 = ConstInput(other_constants);
if (!const_input2) return false;
bool other_first_is_variable = other_constants[0] == nullptr;
uint32_t merged_id = PerformOperation(const_mgr, inst->opcode(),
const_input1, const_input2);
if (merged_id == 0) return false;
uint32_t non_const_id = other_first_is_variable
? other_inst->GetSingleWordInOperand(0u)
: other_inst->GetSingleWordInOperand(1u);
inst->SetInOperands({{SPV_OPERAND_TYPE_ID, {non_const_id}},
{SPV_OPERAND_TYPE_ID, {merged_id}}});
return true;
}
return false;
};
}
// Merges divides into subsequent multiplies if each instruction contains one
// constant operand. Does not support integer operations.
// Cases:
// 2 * (x / 2) = x * 1
// 2 * (2 / x) = 4 / x
// (x / 2) * 2 = x * 1
// (2 / x) * 2 = 4 / x
// (y / x) * x = y
// x * (y / x) = y
FoldingRule MergeMulDivArithmetic() {
return [](IRContext* context, Instruction* inst,
const std::vector<const analysis::Constant*>& constants) {
assert(inst->opcode() == spv::Op::OpFMul);
analysis::ConstantManager* const_mgr = context->get_constant_mgr();
analysis::DefUseManager* def_use_mgr = context->get_def_use_mgr();
const analysis::Type* type =
context->get_type_mgr()->GetType(inst->type_id());
if (IsCooperativeMatrix(type)) {
return false;
}
if (!inst->IsFloatingPointFoldingAllowed()) return false;
uint32_t width = ElementWidth(type);
if (width != 32 && width != 64) return false;
for (uint32_t i = 0; i < 2; i++) {
uint32_t op_id = inst->GetSingleWordInOperand(i);
Instruction* op_inst = def_use_mgr->GetDef(op_id);
if (op_inst->opcode() == spv::Op::OpFDiv) {
if (op_inst->GetSingleWordInOperand(1) ==
inst->GetSingleWordInOperand(1 - i)) {
inst->SetOpcode(spv::Op::OpCopyObject);
inst->SetInOperands(
{{SPV_OPERAND_TYPE_ID, {op_inst->GetSingleWordInOperand(0)}}});
return true;
}
}
}
const analysis::Constant* const_input1 = ConstInput(constants);
if (!const_input1) return false;
Instruction* other_inst = NonConstInput(context, constants[0], inst);
if (!other_inst->IsFloatingPointFoldingAllowed()) return false;
if (other_inst->opcode() == spv::Op::OpFDiv) {
std::vector<const analysis::Constant*> other_constants =
const_mgr->GetOperandConstants(other_inst);
const analysis::Constant* const_input2 = ConstInput(other_constants);
if (!const_input2 || HasZero(const_input2)) return false;
bool other_first_is_variable = other_constants[0] == nullptr;
// If the variable value is the second operand of the divide, multiply
// the constants together. Otherwise divide the constants.
uint32_t merged_id = PerformOperation(
const_mgr,
other_first_is_variable ? other_inst->opcode() : inst->opcode(),
const_input1, const_input2);
if (merged_id == 0) return false;
uint32_t non_const_id = other_first_is_variable
? other_inst->GetSingleWordInOperand(0u)
: other_inst->GetSingleWordInOperand(1u);
// If the variable value is on the second operand of the div, then this
// operation is a div. Otherwise it should be a multiply.
inst->SetOpcode(other_first_is_variable ? inst->opcode()
: other_inst->opcode());
if (other_first_is_variable) {
inst->SetInOperands({{SPV_OPERAND_TYPE_ID, {non_const_id}},
{SPV_OPERAND_TYPE_ID, {merged_id}}});
} else {
inst->SetInOperands({{SPV_OPERAND_TYPE_ID, {merged_id}},
{SPV_OPERAND_TYPE_ID, {non_const_id}}});
}
return true;
}
return false;
};
}
// Merges multiply of constant and negation.
// Cases:
// (-x) * 2 = x * -2
// 2 * (-x) = x * -2
FoldingRule MergeMulNegateArithmetic() {
return [](IRContext* context, Instruction* inst,
const std::vector<const analysis::Constant*>& constants) {
assert(inst->opcode() == spv::Op::OpFMul ||
inst->opcode() == spv::Op::OpIMul);
analysis::ConstantManager* const_mgr = context->get_constant_mgr();
const analysis::Type* type =
context->get_type_mgr()->GetType(inst->type_id());
if (IsCooperativeMatrix(type)) {
return false;
}
bool uses_float = HasFloatingPoint(type);
if (uses_float && !inst->IsFloatingPointFoldingAllowed()) return false;
uint32_t width = ElementWidth(type);
if (width != 32 && width != 64) return false;
const analysis::Constant* const_input1 = ConstInput(constants);
if (!const_input1) return false;
Instruction* other_inst = NonConstInput(context, constants[0], inst);
if (uses_float && !other_inst->IsFloatingPointFoldingAllowed())
return false;
if (other_inst->opcode() == spv::Op::OpFNegate ||
other_inst->opcode() == spv::Op::OpSNegate) {
uint32_t neg_id = NegateConstant(const_mgr, const_input1);
inst->SetInOperands(
{{SPV_OPERAND_TYPE_ID, {other_inst->GetSingleWordInOperand(0u)}},
{SPV_OPERAND_TYPE_ID, {neg_id}}});
return true;
}
return false;
};
}
// Merges consecutive divides if each instruction contains one constant operand.
// Does not support integer division.
// Cases:
// 2 / (x / 2) = 4 / x
// 4 / (2 / x) = 2 * x
// (4 / x) / 2 = 2 / x
// (x / 2) / 2 = x / 4
FoldingRule MergeDivDivArithmetic() {
return [](IRContext* context, Instruction* inst,
const std::vector<const analysis::Constant*>& constants) {
assert(inst->opcode() == spv::Op::OpFDiv);
analysis::ConstantManager* const_mgr = context->get_constant_mgr();
const analysis::Type* type =
context->get_type_mgr()->GetType(inst->type_id());
if (IsCooperativeMatrix(type)) {
return false;
}
if (!inst->IsFloatingPointFoldingAllowed()) return false;
uint32_t width = ElementWidth(type);
if (width != 32 && width != 64) return false;
const analysis::Constant* const_input1 = ConstInput(constants);
if (!const_input1 || HasZero(const_input1)) return false;
Instruction* other_inst = NonConstInput(context, constants[0], inst);
if (!other_inst->IsFloatingPointFoldingAllowed()) return false;
bool first_is_variable = constants[0] == nullptr;
if (other_inst->opcode() == inst->opcode()) {
std::vector<const analysis::Constant*> other_constants =
const_mgr->GetOperandConstants(other_inst);
const analysis::Constant* const_input2 = ConstInput(other_constants);
if (!const_input2 || HasZero(const_input2)) return false;
bool other_first_is_variable = other_constants[0] == nullptr;
spv::Op merge_op = inst->opcode();
if (other_first_is_variable) {
// Constants magnify.
merge_op = spv::Op::OpFMul;
}
// This is an x / (*) case. Swap the inputs. Doesn't harm multiply
// because it is commutative.
if (first_is_variable) std::swap(const_input1, const_input2);
uint32_t merged_id =
PerformOperation(const_mgr, merge_op, const_input1, const_input2);
if (merged_id == 0) return false;
uint32_t non_const_id = other_first_is_variable
? other_inst->GetSingleWordInOperand(0u)
: other_inst->GetSingleWordInOperand(1u);
spv::Op op = inst->opcode();
if (!first_is_variable && !other_first_is_variable) {
// Effectively div of 1/x, so change to multiply.
op = spv::Op::OpFMul;
}
uint32_t op1 = merged_id;
uint32_t op2 = non_const_id;
if (first_is_variable && other_first_is_variable) std::swap(op1, op2);
inst->SetOpcode(op);
inst->SetInOperands(
{{SPV_OPERAND_TYPE_ID, {op1}}, {SPV_OPERAND_TYPE_ID, {op2}}});
return true;
}
return false;
};
}
// Fold multiplies succeeded by divides where each instruction contains a
// constant operand. Does not support integer divide.
// Cases:
// 4 / (x * 2) = 2 / x
// 4 / (2 * x) = 2 / x
// (x * 4) / 2 = x * 2
// (4 * x) / 2 = x * 2
// (x * y) / x = y
// (y * x) / x = y
FoldingRule MergeDivMulArithmetic() {
return [](IRContext* context, Instruction* inst,
const std::vector<const analysis::Constant*>& constants) {
assert(inst->opcode() == spv::Op::OpFDiv);
analysis::DefUseManager* def_use_mgr = context->get_def_use_mgr();
analysis::ConstantManager* const_mgr = context->get_constant_mgr();
const analysis::Type* type =
context->get_type_mgr()->GetType(inst->type_id());
if (IsCooperativeMatrix(type)) {
return false;
}
if (!inst->IsFloatingPointFoldingAllowed()) return false;
uint32_t width = ElementWidth(type);
if (width != 32 && width != 64) return false;
uint32_t op_id = inst->GetSingleWordInOperand(0);
Instruction* op_inst = def_use_mgr->GetDef(op_id);
if (op_inst->opcode() == spv::Op::OpFMul) {
for (uint32_t i = 0; i < 2; i++) {
if (op_inst->GetSingleWordInOperand(i) ==
inst->GetSingleWordInOperand(1)) {
inst->SetOpcode(spv::Op::OpCopyObject);
inst->SetInOperands({{SPV_OPERAND_TYPE_ID,
{op_inst->GetSingleWordInOperand(1 - i)}}});
return true;
}
}
}
const analysis::Constant* const_input1 = ConstInput(constants);
if (!const_input1 || HasZero(const_input1)) return false;
Instruction* other_inst = NonConstInput(context, constants[0], inst);
if (!other_inst->IsFloatingPointFoldingAllowed()) return false;