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SPIRV-Tools/source/opt/folding_rules.cpp
Nicolas Capens 869a550d26
Don't fold unsigned divides of an constant and a negation (#4457) 
Negating an unsigned constant results in its two's complement which is
still interpreted as unsigned. For example -2u becomes 4294967294u.

Fixes https://github.com/KhronosGroup/SPIRV-Tools/issues/4456
2021-08-16 09:56:05 -04:00

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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 {
const uint32_t kExtractCompositeIdInIdx = 0;
const uint32_t kInsertObjectIdInIdx = 0;
const uint32_t kInsertCompositeIdInIdx = 1;
const uint32_t kExtInstSetIdInIdx = 0;
const uint32_t kExtInstInstructionInIdx = 1;
const uint32_t kFMixXIdInIdx = 2;
const uint32_t kFMixYIdInIdx = 3;
const uint32_t kFMixAIdInIdx = 4;
const 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 SpvOpImageSampleImplicitLod:
case SpvOpImageSampleExplicitLod:
case SpvOpImageSampleProjImplicitLod:
case SpvOpImageSampleProjExplicitLod:
case SpvOpImageFetch:
case SpvOpImageRead:
case SpvOpImageSparseSampleImplicitLod:
case SpvOpImageSparseSampleExplicitLod:
case SpvOpImageSparseSampleProjImplicitLod:
case SpvOpImageSparseSampleProjExplicitLod:
case SpvOpImageSparseFetch:
case SpvOpImageSparseRead:
return inst->NumOperands() > 4 ? 2 : -1;
case SpvOpImageSampleDrefImplicitLod:
case SpvOpImageSampleDrefExplicitLod:
case SpvOpImageSampleProjDrefImplicitLod:
case SpvOpImageSampleProjDrefExplicitLod:
case SpvOpImageGather:
case SpvOpImageDrefGather:
case SpvOpImageSparseSampleDrefImplicitLod:
case SpvOpImageSparseSampleDrefExplicitLod:
case SpvOpImageSparseSampleProjDrefImplicitLod:
case SpvOpImageSparseSampleProjDrefExplicitLod:
case SpvOpImageSparseGather:
case SpvOpImageSparseDrefGather:
return inst->NumOperands() > 5 ? 3 : -1;
case SpvOpImageWrite:
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;
}
}
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 == 32 || width == 64);
if (width == 64) {
uint64_t uval = static_cast<uint64_t>(c->GetU64());
return ExtractInts(uval);
}
return {c->GetU32()};
}
std::vector<uint32_t> GetWordsFromScalarFloatConstant(
const analysis::FloatConstant* c) {
assert(c != nullptr);
uint32_t width = c->type()->AsFloat()->width();
assert(width == 32 || width == 64);
if (width == 64) {
utils::FloatProxy<double> result(c->GetDouble());
return result.GetWords();
}
utils::FloatProxy<float> result(c->GetFloat());
return result.GetWords();
}
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) {
if (type->AsInteger() || 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 (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() == SpvOpFDiv);
analysis::ConstantManager* const_mgr = context->get_constant_mgr();
const analysis::Type* type =
context->get_type_mgr()->GetType(inst->type_id());
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(SpvOpFMul);
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() == SpvOpFNegate || inst->opcode() == SpvOpSNegate);
(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(SpvOpCopyObject);
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() == SpvOpFNegate || inst->opcode() == SpvOpSNegate);
(void)constants;
analysis::ConstantManager* const_mgr = context->get_constant_mgr();
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;
uint32_t width = ElementWidth(type);
if (width != 32 && width != 64) return false;
SpvOp opcode = op_inst->opcode();
if (opcode == SpvOpFMul || opcode == SpvOpFDiv || opcode == SpvOpIMul ||
opcode == SpvOpSDiv || opcode == SpvOpUDiv) {
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] || op_constants[1]) {
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 == SpvOpFDiv || opcode == SpvOpUDiv || opcode == SpvOpSDiv) {
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;
}
}
return false;
};
}
// 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() == SpvOpFNegate || inst->opcode() == SpvOpSNegate);
(void)constants;
analysis::ConstantManager* const_mgr = context->get_constant_mgr();
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;
uint32_t width = ElementWidth(type);
if (width != 32 && width != 64) return false;
if (op_inst->opcode() == SpvOpFAdd || op_inst->opcode() == SpvOpFSub ||
op_inst->opcode() == SpvOpIAdd || op_inst->opcode() == SpvOpISub) {
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() == SpvOpFAdd) ||
(op_inst->opcode() == SpvOpIAdd);
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) ? SpvOpFSub : SpvOpISub);
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,
SpvOp 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 SpvOpFMul:
FOLD_OP(*);
break;
case SpvOpFDiv:
if (HasZero(input2)) return 0;
FOLD_OP(/);
break;
case SpvOpFAdd:
FOLD_OP(+);
break;
case SpvOpFSub:
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,
SpvOp 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;
#define FOLD_OP(op) \
if (width == 64) { \
if (type->IsSigned()) { \
int64_t val = input1->GetS64() op input2->GetS64(); \
words = ExtractInts(static_cast<uint64_t>(val)); \
} else { \
uint64_t val = input1->GetU64() op input2->GetU64(); \
words = ExtractInts(val); \
} \
} else { \
if (type->IsSigned()) { \
int32_t val = input1->GetS32() op input2->GetS32(); \
words.push_back(static_cast<uint32_t>(val)); \
} else { \
uint32_t val = input1->GetU32() op input2->GetU32(); \
words.push_back(val); \
} \
} static_assert(true, "require extra semicalon")
switch (opcode) {
case SpvOpIMul:
FOLD_OP(*);
break;
case SpvOpSDiv:
case SpvOpUDiv:
assert(false && "Should not merge integer division");
break;
case SpvOpIAdd:
FOLD_OP(+);
break;
case SpvOpISub:
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, SpvOp 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() == SpvOpFMul || inst->opcode() == SpvOpIMul);
analysis::ConstantManager* const_mgr = context->get_constant_mgr();
const analysis::Type* type =
context->get_type_mgr()->GetType(inst->type_id());
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() == SpvOpFMul);
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 (!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() == SpvOpFDiv) {
if (op_inst->GetSingleWordInOperand(1) ==
inst->GetSingleWordInOperand(1 - i)) {
inst->SetOpcode(SpvOpCopyObject);
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() == SpvOpFDiv) {
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() == SpvOpFMul || inst->opcode() == SpvOpIMul);
analysis::ConstantManager* const_mgr = context->get_constant_mgr();
const analysis::Type* type =
context->get_type_mgr()->GetType(inst->type_id());
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() == SpvOpFNegate ||
other_inst->opcode() == SpvOpSNegate) {
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() == SpvOpFDiv);
analysis::ConstantManager* const_mgr = context->get_constant_mgr();
const analysis::Type* type =
context->get_type_mgr()->GetType(inst->type_id());
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;
SpvOp merge_op = inst->opcode();
if (other_first_is_variable) {
// Constants magnify.
merge_op = SpvOpFMul;
}
// 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);
SpvOp op = inst->opcode();
if (!first_is_variable && !other_first_is_variable) {
// Effectively div of 1/x, so change to multiply.
op = SpvOpFMul;
}
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() == SpvOpFDiv);
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 (!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() == SpvOpFMul) {
for (uint32_t i = 0; i < 2; i++) {
if (op_inst->GetSingleWordInOperand(i) ==
inst->GetSingleWordInOperand(1)) {
inst->SetOpcode(SpvOpCopyObject);
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;
bool first_is_variable = constants[0] == nullptr;
if (other_inst->opcode() == SpvOpFMul) {
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;
// This is an x / (*) case. Swap the inputs.
if (first_is_variable) std::swap(const_input1, const_input2);
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);
uint32_t op1 = merged_id;
uint32_t op2 = non_const_id;
if (first_is_variable) std::swap(op1, op2);
// Convert to multiply
if (first_is_variable) inst->SetOpcode(other_inst->opcode());
inst->SetInOperands(
{{SPV_OPERAND_TYPE_ID, {op1}}, {SPV_OPERAND_TYPE_ID, {op2}}});
return true;
}
return false;
};
}
// Fold divides of a constant and a negation.
// Cases:
// (-x) / 2 = x / -2
// 2 / (-x) = -2 / x
FoldingRule MergeDivNegateArithmetic() {
return [](IRContext* context, Instruction* inst,
const std::vector<const analysis::Constant*>& constants) {
assert(inst->opcode() == SpvOpFDiv || inst->opcode() == SpvOpSDiv);
analysis::ConstantManager* const_mgr = context->get_constant_mgr();
const analysis::Type* type =
context->get_type_mgr()->GetType(inst->type_id());
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;
bool first_is_variable = constants[0] == nullptr;
if (other_inst->opcode() == SpvOpFNegate ||
other_inst->opcode() == SpvOpSNegate) {
uint32_t neg_id = NegateConstant(const_mgr, const_input1);
if (first_is_variable) {
inst->SetInOperands(
{{SPV_OPERAND_TYPE_ID, {other_inst->GetSingleWordInOperand(0u)}},
{SPV_OPERAND_TYPE_ID, {neg_id}}});
} else {
inst->SetInOperands(
{{SPV_OPERAND_TYPE_ID, {neg_id}},
{SPV_OPERAND_TYPE_ID, {other_inst->GetSingleWordInOperand(0u)}}});
}
return true;
}
return false;
};
}
// Folds addition of a constant and a negation.
// Cases:
// (-x) + 2 = 2 - x
// 2 + (-x) = 2 - x
FoldingRule MergeAddNegateArithmetic() {
return [](IRContext* context, Instruction* inst,
const std::vector<const analysis::Constant*>& constants) {
assert(inst->opcode() == SpvOpFAdd || inst->opcode() == SpvOpIAdd);
const analysis::Type* type =
context->get_type_mgr()->GetType(inst->type_id());
bool uses_float = HasFloatingPoint(type);
if (uses_float && !inst->IsFloatingPointFoldingAllowed()) 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() == SpvOpSNegate ||
other_inst->opcode() == SpvOpFNegate) {
inst->SetOpcode(HasFloatingPoint(type) ? SpvOpFSub : SpvOpISub);
uint32_t const_id = constants[0] ? inst->GetSingleWordInOperand(0u)
: inst->GetSingleWordInOperand(1u);
inst->SetInOperands(
{{SPV_OPERAND_TYPE_ID, {const_id}},
{SPV_OPERAND_TYPE_ID, {other_inst->GetSingleWordInOperand(0u)}}});
return true;
}
return false;
};
}
// Folds subtraction of a constant and a negation.
// Cases:
// (-x) - 2 = -2 - x
// 2 - (-x) = x + 2
FoldingRule MergeSubNegateArithmetic() {
return [](IRContext* context, Instruction* inst,
const std::vector<const analysis::Constant*>& constants) {
assert(inst->opcode() == SpvOpFSub || inst->opcode() == SpvOpISub);
analysis::ConstantManager* const_mgr = context->get_constant_mgr();
const analysis::Type* type =
context->get_type_mgr()->GetType(inst->type_id());
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() == SpvOpSNegate ||
other_inst->opcode() == SpvOpFNegate) {
uint32_t op1 = 0;
uint32_t op2 = 0;
SpvOp opcode = inst->opcode();
if (constants[0] != nullptr) {
op1 = other_inst->GetSingleWordInOperand(0u);
op2 = inst->GetSingleWordInOperand(0u);
opcode = HasFloatingPoint(type) ? SpvOpFAdd : SpvOpIAdd;
} else {
op1 = NegateConstant(const_mgr, const_input1);
op2 = other_inst->GetSingleWordInOperand(0u);
}
inst->SetOpcode(opcode);
inst->SetInOperands(
{{SPV_OPERAND_TYPE_ID, {op1}}, {SPV_OPERAND_TYPE_ID, {op2}}});
return true;
}
return false;
};
}
// Folds addition of an addition where each operation has a constant operand.
// Cases:
// (x + 2) + 2 = x + 4
// (2 + x) + 2 = x + 4
// 2 + (x + 2) = x + 4
// 2 + (2 + x) = x + 4
FoldingRule MergeAddAddArithmetic() {
return [](IRContext* context, Instruction* inst,
const std::vector<const analysis::Constant*>& constants) {
assert(inst->opcode() == SpvOpFAdd || inst->opcode() == SpvOpIAdd);
const analysis::Type* type =
context->get_type_mgr()->GetType(inst->type_id());
analysis::ConstantManager* const_mgr = context->get_constant_mgr();
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() == SpvOpFAdd ||
other_inst->opcode() == SpvOpIAdd) {
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;
Instruction* non_const_input =
NonConstInput(context, other_constants[0], other_inst);
uint32_t merged_id = PerformOperation(const_mgr, inst->opcode(),
const_input1, const_input2);
if (merged_id == 0) return false;
inst->SetInOperands(
{{SPV_OPERAND_TYPE_ID, {non_const_input->result_id()}},
{SPV_OPERAND_TYPE_ID, {merged_id}}});
return true;
}
return false;
};
}
// Folds addition of a subtraction where each operation has a constant operand.
// Cases:
// (x - 2) + 2 = x + 0
// (2 - x) + 2 = 4 - x
// 2 + (x - 2) = x + 0
// 2 + (2 - x) = 4 - x
FoldingRule MergeAddSubArithmetic() {
return [](IRContext* context, Instruction* inst,
const std::vector<const analysis::Constant*>& constants) {
assert(inst->opcode() == SpvOpFAdd || inst->opcode() == SpvOpIAdd);
const analysis::Type* type =
context->get_type_mgr()->GetType(inst->type_id());
analysis::ConstantManager* const_mgr = context->get_constant_mgr();
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() == SpvOpFSub ||
other_inst->opcode() == SpvOpISub) {
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 first_is_variable = other_constants[0] == nullptr;
SpvOp op = inst->opcode();
uint32_t op1 = 0;
uint32_t op2 = 0;
if (first_is_variable) {
// Subtract constants. Non-constant operand is first.
op1 = other_inst->GetSingleWordInOperand(0u);
op2 = PerformOperation(const_mgr, other_inst->opcode(), const_input1,
const_input2);
} else {
// Add constants. Constant operand is first. Change the opcode.
op1 = PerformOperation(const_mgr, inst->opcode(), const_input1,
const_input2);
op2 = other_inst->GetSingleWordInOperand(1u);
op = other_inst->opcode();
}
if (op1 == 0 || op2 == 0) return false;
inst->SetOpcode(op);
inst->SetInOperands(
{{SPV_OPERAND_TYPE_ID, {op1}}, {SPV_OPERAND_TYPE_ID, {op2}}});
return true;
}
return false;
};
}
// Folds subtraction of an addition where each operand has a constant operand.
// Cases:
// (x + 2) - 2 = x + 0
// (2 + x) - 2 = x + 0
// 2 - (x + 2) = 0 - x
// 2 - (2 + x) = 0 - x
FoldingRule MergeSubAddArithmetic() {
return [](IRContext* context, Instruction* inst,
const std::vector<const analysis::Constant*>& constants) {
assert(inst->opcode() == SpvOpFSub || inst->opcode() == SpvOpISub);
const analysis::Type* type =
context->get_type_mgr()->GetType(inst->type_id());
analysis::ConstantManager* const_mgr = context->get_constant_mgr();
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() == SpvOpFAdd ||
other_inst->opcode() == SpvOpIAdd) {
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;
Instruction* non_const_input =
NonConstInput(context, other_constants[0], other_inst);
// If the first operand of the sub is not a constant, swap the constants
// so the subtraction has the correct operands.
if (constants[0] == nullptr) std::swap(const_input1, const_input2);
// Subtract the constants.
uint32_t merged_id = PerformOperation(const_mgr, inst->opcode(),
const_input1, const_input2);
SpvOp op = inst->opcode();
uint32_t op1 = 0;
uint32_t op2 = 0;
if (constants[0] == nullptr) {
// Non-constant operand is first. Change the opcode.
op1 = non_const_input->result_id();
op2 = merged_id;
op = other_inst->opcode();
} else {
// Constant operand is first.
op1 = merged_id;
op2 = non_const_input->result_id();
}
if (op1 == 0 || op2 == 0) return false;
inst->SetOpcode(op);
inst->SetInOperands(
{{SPV_OPERAND_TYPE_ID, {op1}}, {SPV_OPERAND_TYPE_ID, {op2}}});
return true;
}
return false;
};
}
// Folds subtraction of a subtraction where each operand has a constant operand.
// Cases:
// (x - 2) - 2 = x - 4
// (2 - x) - 2 = 0 - x
// 2 - (x - 2) = 4 - x
// 2 - (2 - x) = x + 0
FoldingRule MergeSubSubArithmetic() {
return [](IRContext* context, Instruction* inst,
const std::vector<const analysis::Constant*>& constants) {
assert(inst->opcode() == SpvOpFSub || inst->opcode() == SpvOpISub);
const analysis::Type* type =
context->get_type_mgr()->GetType(inst->type_id());
analysis::ConstantManager* const_mgr = context->get_constant_mgr();
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() == SpvOpFSub ||
other_inst->opcode() == SpvOpISub) {
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;
Instruction* non_const_input =
NonConstInput(context, other_constants[0], other_inst);
// Merge the constants.
uint32_t merged_id = 0;
SpvOp merge_op = inst->opcode();
if (other_constants[0] == nullptr) {
merge_op = uses_float ? SpvOpFAdd : SpvOpIAdd;
} else if (constants[0] == nullptr) {
std::swap(const_input1, const_input2);
}
merged_id =
PerformOperation(const_mgr, merge_op, const_input1, const_input2);
if (merged_id == 0) return false;
SpvOp op = inst->opcode();
if (constants[0] != nullptr && other_constants[0] != nullptr) {
// Change the operation.
op = uses_float ? SpvOpFAdd : SpvOpIAdd;
}
uint32_t op1 = 0;
uint32_t op2 = 0;
if ((constants[0] == nullptr) ^ (other_constants[0] == nullptr)) {
op1 = merged_id;
op2 = non_const_input->result_id();
} else {
op1 = non_const_input->result_id();
op2 = merged_id;
}
inst->SetOpcode(op);
inst->SetInOperands(
{{SPV_OPERAND_TYPE_ID, {op1}}, {SPV_OPERAND_TYPE_ID, {op2}}});
return true;
}
return false;
};
}
// Helper function for MergeGenericAddSubArithmetic. If |addend| and
// subtrahend of |sub| is the same, merge to copy of minuend of |sub|.
bool MergeGenericAddendSub(uint32_t addend, uint32_t sub, Instruction* inst) {
IRContext* context = inst->context();
analysis::DefUseManager* def_use_mgr = context->get_def_use_mgr();
Instruction* sub_inst = def_use_mgr->GetDef(sub);
if (sub_inst->opcode() != SpvOpFSub && sub_inst->opcode() != SpvOpISub)
return false;
if (sub_inst->opcode() == SpvOpFSub &&
!sub_inst->IsFloatingPointFoldingAllowed())
return false;
if (addend != sub_inst->GetSingleWordInOperand(1)) return false;
inst->SetOpcode(SpvOpCopyObject);
inst->SetInOperands(
{{SPV_OPERAND_TYPE_ID, {sub_inst->GetSingleWordInOperand(0)}}});
context->UpdateDefUse(inst);
return true;
}
// Folds addition of a subtraction where the subtrahend is equal to the
// other addend. Return a copy of the minuend. Accepts generic (const and
// non-const) operands.
// Cases:
// (a - b) + b = a
// b + (a - b) = a
FoldingRule MergeGenericAddSubArithmetic() {
return [](IRContext* context, Instruction* inst,
const std::vector<const analysis::Constant*>&) {
assert(inst->opcode() == SpvOpFAdd || inst->opcode() == SpvOpIAdd);
const analysis::Type* type =
context->get_type_mgr()->GetType(inst->type_id());
bool uses_float = HasFloatingPoint(type);
if (uses_float && !inst->IsFloatingPointFoldingAllowed()) return false;
uint32_t width = ElementWidth(type);
if (width != 32 && width != 64) return false;
uint32_t add_op0 = inst->GetSingleWordInOperand(0);
uint32_t add_op1 = inst->GetSingleWordInOperand(1);
if (MergeGenericAddendSub(add_op0, add_op1, inst)) return true;
return MergeGenericAddendSub(add_op1, add_op0, inst);
};
}
// Helper function for FactorAddMuls. If |factor0_0| is the same as |factor1_0|,
// generate |factor0_0| * (|factor0_1| + |factor1_1|).
bool FactorAddMulsOpnds(uint32_t factor0_0, uint32_t factor0_1,
uint32_t factor1_0, uint32_t factor1_1,
Instruction* inst) {
IRContext* context = inst->context();
if (factor0_0 != factor1_0) return false;
InstructionBuilder ir_builder(
context, inst,
IRContext::kAnalysisDefUse | IRContext::kAnalysisInstrToBlockMapping);
Instruction* new_add_inst = ir_builder.AddBinaryOp(
inst->type_id(), inst->opcode(), factor0_1, factor1_1);
inst->SetOpcode(inst->opcode() == SpvOpFAdd ? SpvOpFMul : SpvOpIMul);
inst->SetInOperands({{SPV_OPERAND_TYPE_ID, {factor0_0}},
{SPV_OPERAND_TYPE_ID, {new_add_inst->result_id()}}});
context->UpdateDefUse(inst);
return true;
}
// Perform the following factoring identity, handling all operand order
// combinations: (a * b) + (a * c) = a * (b + c)
FoldingRule FactorAddMuls() {
return [](IRContext* context, Instruction* inst,
const std::vector<const analysis::Constant*>&) {
assert(inst->opcode() == SpvOpFAdd || inst->opcode() == SpvOpIAdd);
const analysis::Type* type =
context->get_type_mgr()->GetType(inst->type_id());
bool uses_float = HasFloatingPoint(type);
if (uses_float && !inst->IsFloatingPointFoldingAllowed()) return false;
analysis::DefUseManager* def_use_mgr = context->get_def_use_mgr();
uint32_t add_op0 = inst->GetSingleWordInOperand(0);
Instruction* add_op0_inst = def_use_mgr->GetDef(add_op0);
if (add_op0_inst->opcode() != SpvOpFMul &&
add_op0_inst->opcode() != SpvOpIMul)
return false;
uint32_t add_op1 = inst->GetSingleWordInOperand(1);
Instruction* add_op1_inst = def_use_mgr->GetDef(add_op1);
if (add_op1_inst->opcode() != SpvOpFMul &&
add_op1_inst->opcode() != SpvOpIMul)
return false;
// Only perform this optimization if both of the muls only have one use.
// Otherwise this is a deoptimization in size and performance.
if (def_use_mgr->NumUses(add_op0_inst) > 1) return false;
if (def_use_mgr->NumUses(add_op1_inst) > 1) return false;
if (add_op0_inst->opcode() == SpvOpFMul &&
(!add_op0_inst->IsFloatingPointFoldingAllowed() ||
!add_op1_inst->IsFloatingPointFoldingAllowed()))
return false;
for (int i = 0; i < 2; i++) {
for (int j = 0; j < 2; j++) {
// Check if operand i in add_op0_inst matches operand j in add_op1_inst.
if (FactorAddMulsOpnds(add_op0_inst->GetSingleWordInOperand(i),
add_op0_inst->GetSingleWordInOperand(1 - i),
add_op1_inst->GetSingleWordInOperand(j),
add_op1_inst->GetSingleWordInOperand(1 - j),
inst))
return true;
}
}
return false;
};
}
FoldingRule IntMultipleBy1() {
return [](IRContext*, Instruction* inst,
const std::vector<const analysis::Constant*>& constants) {
assert(inst->opcode() == SpvOpIMul && "Wrong opcode. Should be OpIMul.");
for (uint32_t i = 0; i < 2; i++) {
if (constants[i] == nullptr) {
continue;
}
const analysis::IntConstant* int_constant = constants[i]->AsIntConstant();
if (int_constant) {
uint32_t width = ElementWidth(int_constant->type());
if (width != 32 && width != 64) return false;
bool is_one = (width == 32) ? int_constant->GetU32BitValue() == 1u
: int_constant->GetU64BitValue() == 1ull;
if (is_one) {
inst->SetOpcode(SpvOpCopyObject);
inst->SetInOperands(
{{SPV_OPERAND_TYPE_ID, {inst->GetSingleWordInOperand(1 - i)}}});
return true;
}
}
}
return false;
};
}
FoldingRule CompositeConstructFeedingExtract() {
return [](IRContext* context, Instruction* inst,
const std::vector<const analysis::Constant*>&) {
// If the input to an OpCompositeExtract is an OpCompositeConstruct,
// then we can simply use the appropriate element in the construction.
assert(inst->opcode() == SpvOpCompositeExtract &&
"Wrong opcode. Should be OpCompositeExtract.");
analysis::DefUseManager* def_use_mgr = context->get_def_use_mgr();
analysis::TypeManager* type_mgr = context->get_type_mgr();
// If there are no index operands, then this rule cannot do anything.
if (inst->NumInOperands() <= 1) {
return false;
}
uint32_t cid = inst->GetSingleWordInOperand(kExtractCompositeIdInIdx);
Instruction* cinst = def_use_mgr->GetDef(cid);
if (cinst->opcode() != SpvOpCompositeConstruct) {
return false;
}
std::vector<Operand> operands;
analysis::Type* composite_type = type_mgr->GetType(cinst->type_id());
if (composite_type->AsVector() == nullptr) {
// Get the element being extracted from the OpCompositeConstruct
// Since it is not a vector, it is simple to extract the single element.
uint32_t element_index = inst->GetSingleWordInOperand(1);
uint32_t element_id = cinst->GetSingleWordInOperand(element_index);
operands.push_back({SPV_OPERAND_TYPE_ID, {element_id}});
// Add the remaining indices for extraction.
for (uint32_t i = 2; i < inst->NumInOperands(); ++i) {
operands.push_back({SPV_OPERAND_TYPE_LITERAL_INTEGER,
{inst->GetSingleWordInOperand(i)}});
}
} else {
// With vectors we have to handle the case where it is concatenating
// vectors.
assert(inst->NumInOperands() == 2 &&
"Expecting a vector of scalar values.");
uint32_t element_index = inst->GetSingleWordInOperand(1);
for (uint32_t construct_index = 0;
construct_index < cinst->NumInOperands(); ++construct_index) {
uint32_t element_id = cinst->GetSingleWordInOperand(construct_index);
Instruction* element_def = def_use_mgr->GetDef(element_id);
analysis::Vector* element_type =
type_mgr->GetType(element_def->type_id())->AsVector();
if (element_type) {
uint32_t vector_size = element_type->element_count();
if (vector_size <= element_index) {
// The element we want comes after this vector.
element_index -= vector_size;
} else {
// We want an element of this vector.
operands.push_back({SPV_OPERAND_TYPE_ID, {element_id}});
operands.push_back(
{SPV_OPERAND_TYPE_LITERAL_INTEGER, {element_index}});
break;
}
} else {
if (element_index == 0) {
// This is a scalar, and we this is the element we are extracting.
operands.push_back({SPV_OPERAND_TYPE_ID, {element_id}});
break;
} else {
// Skip over this scalar value.
--element_index;
}
}
}
}
// If there were no extra indices, then we have the final object. No need
// to extract even more.
if (operands.size() == 1) {
inst->SetOpcode(SpvOpCopyObject);
}
inst->SetInOperands(std::move(operands));
return true;
};
}
// If the OpCompositeConstruct is simply putting back together elements that
// where extracted from the same source, we can simply reuse the source.
//
// This is a common code pattern because of the way that scalar replacement
// works.
bool CompositeExtractFeedingConstruct(
IRContext* context, Instruction* inst,
const std::vector<const analysis::Constant*>&) {
assert(inst->opcode() == SpvOpCompositeConstruct &&
"Wrong opcode. Should be OpCompositeConstruct.");
analysis::DefUseManager* def_use_mgr = context->get_def_use_mgr();
uint32_t original_id = 0;
if (inst->NumInOperands() == 0) {
// The struct being constructed has no members.
return false;
}
// Check each element to make sure they are:
// - extractions
// - extracting the same position they are inserting
// - all extract from the same id.
for (uint32_t i = 0; i < inst->NumInOperands(); ++i) {
const uint32_t element_id = inst->GetSingleWordInOperand(i);
Instruction* element_inst = def_use_mgr->GetDef(element_id);
if (element_inst->opcode() != SpvOpCompositeExtract) {
return false;
}
if (element_inst->NumInOperands() != 2) {
return false;
}
if (element_inst->GetSingleWordInOperand(1) != i) {
return false;
}
if (i == 0) {
original_id =
element_inst->GetSingleWordInOperand(kExtractCompositeIdInIdx);
} else if (original_id !=
element_inst->GetSingleWordInOperand(kExtractCompositeIdInIdx)) {
return false;
}
}
// The last check it to see that the object being extracted from is the
// correct type.
Instruction* original_inst = def_use_mgr->GetDef(original_id);
if (original_inst->type_id() != inst->type_id()) {
return false;
}
// Simplify by using the original object.
inst->SetOpcode(SpvOpCopyObject);
inst->SetInOperands({{SPV_OPERAND_TYPE_ID, {original_id}}});
return true;
}
FoldingRule InsertFeedingExtract() {
return [](IRContext* context, Instruction* inst,
const std::vector<const analysis::Constant*>&) {
assert(inst->opcode() == SpvOpCompositeExtract &&
"Wrong opcode. Should be OpCompositeExtract.");
analysis::DefUseManager* def_use_mgr = context->get_def_use_mgr();
uint32_t cid = inst->GetSingleWordInOperand(kExtractCompositeIdInIdx);
Instruction* cinst = def_use_mgr->GetDef(cid);
if (cinst->opcode() != SpvOpCompositeInsert) {
return false;
}
// Find the first position where the list of insert and extract indicies
// differ, if at all.
uint32_t i;
for (i = 1; i < inst->NumInOperands(); ++i) {
if (i + 1 >= cinst->NumInOperands()) {
break;
}
if (inst->GetSingleWordInOperand(i) !=
cinst->GetSingleWordInOperand(i + 1)) {
break;
}
}
// We are extracting the element that was inserted.
if (i == inst->NumInOperands() && i + 1 == cinst->NumInOperands()) {
inst->SetOpcode(SpvOpCopyObject);
inst->SetInOperands(
{{SPV_OPERAND_TYPE_ID,
{cinst->GetSingleWordInOperand(kInsertObjectIdInIdx)}}});
return true;
}
// Extracting the value that was inserted along with values for the base
// composite. Cannot do anything.
if (i == inst->NumInOperands()) {
return false;
}
// Extracting an element of the value that was inserted. Extract from
// that value directly.
if (i + 1 == cinst->NumInOperands()) {
std::vector<Operand> operands;
operands.push_back(
{SPV_OPERAND_TYPE_ID,
{cinst->GetSingleWordInOperand(kInsertObjectIdInIdx)}});
for (; i < inst->NumInOperands(); ++i) {
operands.push_back({SPV_OPERAND_TYPE_LITERAL_INTEGER,
{inst->GetSingleWordInOperand(i)}});
}
inst->SetInOperands(std::move(operands));
return true;
}
// Extracting a value that is disjoint from the element being inserted.
// Rewrite the extract to use the composite input to the insert.
std::vector<Operand> operands;
operands.push_back(
{SPV_OPERAND_TYPE_ID,
{cinst->GetSingleWordInOperand(kInsertCompositeIdInIdx)}});
for (i = 1; i < inst->NumInOperands(); ++i) {
operands.push_back({SPV_OPERAND_TYPE_LITERAL_INTEGER,
{inst->GetSingleWordInOperand(i)}});
}
inst->SetInOperands(std::move(operands));
return true;
};
}
// When a VectorShuffle is feeding an Extract, we can extract from one of the
// operands of the VectorShuffle. We just need to adjust the index in the
// extract instruction.
FoldingRule VectorShuffleFeedingExtract() {
return [](IRContext* context, Instruction* inst,
const std::vector<const analysis::Constant*>&) {
assert(inst->opcode() == SpvOpCompositeExtract &&
"Wrong opcode. Should be OpCompositeExtract.");
analysis::DefUseManager* def_use_mgr = context->get_def_use_mgr();
analysis::TypeManager* type_mgr = context->get_type_mgr();
uint32_t cid = inst->GetSingleWordInOperand(kExtractCompositeIdInIdx);
Instruction* cinst = def_use_mgr->GetDef(cid);
if (cinst->opcode() != SpvOpVectorShuffle) {
return false;
}
// Find the size of the first vector operand of the VectorShuffle
Instruction* first_input =
def_use_mgr->GetDef(cinst->GetSingleWordInOperand(0));
analysis::Type* first_input_type =
type_mgr->GetType(first_input->type_id());
assert(first_input_type->AsVector() &&
"Input to vector shuffle should be vectors.");
uint32_t first_input_size = first_input_type->AsVector()->element_count();
// Get index of the element the vector shuffle is placing in the position
// being extracted.
uint32_t new_index =
cinst->GetSingleWordInOperand(2 + inst->GetSingleWordInOperand(1));
// Extracting an undefined value so fold this extract into an undef.
const uint32_t undef_literal_value = 0xffffffff;
if (new_index == undef_literal_value) {
inst->SetOpcode(SpvOpUndef);
inst->SetInOperands({});
return true;
}
// Get the id of the of the vector the elemtent comes from, and update the
// index if needed.
uint32_t new_vector = 0;
if (new_index < first_input_size) {
new_vector = cinst->GetSingleWordInOperand(0);
} else {
new_vector = cinst->GetSingleWordInOperand(1);
new_index -= first_input_size;
}
// Update the extract instruction.
inst->SetInOperand(kExtractCompositeIdInIdx, {new_vector});
inst->SetInOperand(1, {new_index});
return true;
};
}
// When an FMix with is feeding an Extract that extracts an element whose
// corresponding |a| in the FMix is 0 or 1, we can extract from one of the
// operands of the FMix.
FoldingRule FMixFeedingExtract() {
return [](IRContext* context, Instruction* inst,
const std::vector<const analysis::Constant*>&) {
assert(inst->opcode() == SpvOpCompositeExtract &&
"Wrong opcode. Should be OpCompositeExtract.");
analysis::DefUseManager* def_use_mgr = context->get_def_use_mgr();
analysis::ConstantManager* const_mgr = context->get_constant_mgr();
uint32_t composite_id =
inst->GetSingleWordInOperand(kExtractCompositeIdInIdx);
Instruction* composite_inst = def_use_mgr->GetDef(composite_id);
if (composite_inst->opcode() != SpvOpExtInst) {
return false;
}
uint32_t inst_set_id =
context->get_feature_mgr()->GetExtInstImportId_GLSLstd450();
if (composite_inst->GetSingleWordInOperand(kExtInstSetIdInIdx) !=
inst_set_id ||
composite_inst->GetSingleWordInOperand(kExtInstInstructionInIdx) !=
GLSLstd450FMix) {
return false;
}
// Get the |a| for the FMix instruction.
uint32_t a_id = composite_inst->GetSingleWordInOperand(kFMixAIdInIdx);
std::unique_ptr<Instruction> a(inst->Clone(context));
a->SetInOperand(kExtractCompositeIdInIdx, {a_id});
context->get_instruction_folder().FoldInstruction(a.get());
if (a->opcode() != SpvOpCopyObject) {
return false;
}
const analysis::Constant* a_const =
const_mgr->FindDeclaredConstant(a->GetSingleWordInOperand(0));
if (!a_const) {
return false;
}
bool use_x = false;
assert(a_const->type()->AsFloat());
double element_value = a_const->GetValueAsDouble();
if (element_value == 0.0) {
use_x = true;
} else if (element_value == 1.0) {
use_x = false;
} else {
return false;
}
// Get the id of the of the vector the element comes from.
uint32_t new_vector = 0;
if (use_x) {
new_vector = composite_inst->GetSingleWordInOperand(kFMixXIdInIdx);
} else {
new_vector = composite_inst->GetSingleWordInOperand(kFMixYIdInIdx);
}
// Update the extract instruction.
inst->SetInOperand(kExtractCompositeIdInIdx, {new_vector});
return true;
};
}
FoldingRule RedundantPhi() {
// An OpPhi instruction where all values are the same or the result of the phi
// itself, can be replaced by the value itself.
return [](IRContext*, Instruction* inst,
const std::vector<const analysis::Constant*>&) {
assert(inst->opcode() == SpvOpPhi && "Wrong opcode. Should be OpPhi.");
uint32_t incoming_value = 0;
for (uint32_t i = 0; i < inst->NumInOperands(); i += 2) {
uint32_t op_id = inst->GetSingleWordInOperand(i);
if (op_id == inst->result_id()) {
continue;
}
if (incoming_value == 0) {
incoming_value = op_id;
} else if (op_id != incoming_value) {
// Found two possible value. Can't simplify.
return false;
}
}
if (incoming_value == 0) {
// Code looks invalid. Don't do anything.
return false;
}
// We have a single incoming value. Simplify using that value.
inst->SetOpcode(SpvOpCopyObject);
inst->SetInOperands({{SPV_OPERAND_TYPE_ID, {incoming_value}}});
return true;
};
}
FoldingRule BitCastScalarOrVector() {
return [](IRContext* context, Instruction* inst,
const std::vector<const analysis::Constant*>& constants) {
assert(inst->opcode() == SpvOpBitcast && constants.size() == 1);
if (constants[0] == nullptr) return false;
const analysis::Type* type =
context->get_type_mgr()->GetType(inst->type_id());
if (HasFloatingPoint(type) && !inst->IsFloatingPointFoldingAllowed())
return false;
analysis::ConstantManager* const_mgr = context->get_constant_mgr();
std::vector<uint32_t> words =
GetWordsFromNumericScalarOrVectorConstant(const_mgr, constants[0]);
if (words.size() == 0) return false;
const analysis::Constant* bitcasted_constant =
ConvertWordsToNumericScalarOrVectorConstant(const_mgr, words, type);
if (!bitcasted_constant) return false;
auto new_feeder_id =
const_mgr->GetDefiningInstruction(bitcasted_constant, inst->type_id())
->result_id();
inst->SetOpcode(SpvOpCopyObject);
inst->SetInOperands({{SPV_OPERAND_TYPE_ID, {new_feeder_id}}});
return true;
};
}
FoldingRule RedundantSelect() {
// An OpSelect instruction where both values are the same or the condition is
// constant can be replaced by one of the values
return [](IRContext*, Instruction* inst,
const std::vector<const analysis::Constant*>& constants) {
assert(inst->opcode() == SpvOpSelect &&
"Wrong opcode. Should be OpSelect.");
assert(inst->NumInOperands() == 3);
assert(constants.size() == 3);
uint32_t true_id = inst->GetSingleWordInOperand(1);
uint32_t false_id = inst->GetSingleWordInOperand(2);
if (true_id == false_id) {
// Both results are the same, condition doesn't matter
inst->SetOpcode(SpvOpCopyObject);
inst->SetInOperands({{SPV_OPERAND_TYPE_ID, {true_id}}});
return true;
} else if (constants[0]) {
const analysis::Type* type = constants[0]->type();
if (type->AsBool()) {
// Scalar constant value, select the corresponding value.
inst->SetOpcode(SpvOpCopyObject);
if (constants[0]->AsNullConstant() ||
!constants[0]->AsBoolConstant()->value()) {
inst->SetInOperands({{SPV_OPERAND_TYPE_ID, {false_id}}});
} else {
inst->SetInOperands({{SPV_OPERAND_TYPE_ID, {true_id}}});
}
return true;
} else {
assert(type->AsVector());
if (constants[0]->AsNullConstant()) {
// All values come from false id.
inst->SetOpcode(SpvOpCopyObject);
inst->SetInOperands({{SPV_OPERAND_TYPE_ID, {false_id}}});
return true;
} else {
// Convert to a vector shuffle.
std::vector<Operand> ops;
ops.push_back({SPV_OPERAND_TYPE_ID, {true_id}});
ops.push_back({SPV_OPERAND_TYPE_ID, {false_id}});
const analysis::VectorConstant* vector_const =
constants[0]->AsVectorConstant();
uint32_t size =
static_cast<uint32_t>(vector_const->GetComponents().size());
for (uint32_t i = 0; i != size; ++i) {
const analysis::Constant* component =
vector_const->GetComponents()[i];
if (component->AsNullConstant() ||
!component->AsBoolConstant()->value()) {
// Selecting from the false vector which is the second input
// vector to the shuffle. Offset the index by |size|.
ops.push_back({SPV_OPERAND_TYPE_LITERAL_INTEGER, {i + size}});
} else {
// Selecting from true vector which is the first input vector to
// the shuffle.
ops.push_back({SPV_OPERAND_TYPE_LITERAL_INTEGER, {i}});
}
}
inst->SetOpcode(SpvOpVectorShuffle);
inst->SetInOperands(std::move(ops));
return true;
}
}
}
return false;
};
}
enum class FloatConstantKind { Unknown, Zero, One };
FloatConstantKind getFloatConstantKind(const analysis::Constant* constant) {
if (constant == nullptr) {
return FloatConstantKind::Unknown;
}
assert(HasFloatingPoint(constant->type()) && "Unexpected constant type");
if (constant->AsNullConstant()) {
return FloatConstantKind::Zero;
} else if (const analysis::VectorConstant* vc =
constant->AsVectorConstant()) {
const std::vector<const analysis::Constant*>& components =
vc->GetComponents();
assert(!components.empty());
FloatConstantKind kind = getFloatConstantKind(components[0]);
for (size_t i = 1; i < components.size(); ++i) {
if (getFloatConstantKind(components[i]) != kind) {
return FloatConstantKind::Unknown;
}
}
return kind;
} else if (const analysis::FloatConstant* fc = constant->AsFloatConstant()) {
if (fc->IsZero()) return FloatConstantKind::Zero;
uint32_t width = fc->type()->AsFloat()->width();
if (width != 32 && width != 64) return FloatConstantKind::Unknown;
double value = (width == 64) ? fc->GetDoubleValue() : fc->GetFloatValue();
if (value == 0.0) {
return FloatConstantKind::Zero;
} else if (value == 1.0) {
return FloatConstantKind::One;
} else {
return FloatConstantKind::Unknown;
}
} else {
return FloatConstantKind::Unknown;
}
}
FoldingRule RedundantFAdd() {
return [](IRContext*, Instruction* inst,
const std::vector<const analysis::Constant*>& constants) {
assert(inst->opcode() == SpvOpFAdd && "Wrong opcode. Should be OpFAdd.");
assert(constants.size() == 2);
if (!inst->IsFloatingPointFoldingAllowed()) {
return false;
}
FloatConstantKind kind0 = getFloatConstantKind(constants[0]);
FloatConstantKind kind1 = getFloatConstantKind(constants[1]);
if (kind0 == FloatConstantKind::Zero || kind1 == FloatConstantKind::Zero) {
inst->SetOpcode(SpvOpCopyObject);
inst->SetInOperands({{SPV_OPERAND_TYPE_ID,
{inst->GetSingleWordInOperand(
kind0 == FloatConstantKind::Zero ? 1 : 0)}}});
return true;
}
return false;
};
}
FoldingRule RedundantFSub() {
return [](IRContext*, Instruction* inst,
const std::vector<const analysis::Constant*>& constants) {
assert(inst->opcode() == SpvOpFSub && "Wrong opcode. Should be OpFSub.");
assert(constants.size() == 2);
if (!inst->IsFloatingPointFoldingAllowed()) {
return false;
}
FloatConstantKind kind0 = getFloatConstantKind(constants[0]);
FloatConstantKind kind1 = getFloatConstantKind(constants[1]);
if (kind0 == FloatConstantKind::Zero) {
inst->SetOpcode(SpvOpFNegate);
inst->SetInOperands(
{{SPV_OPERAND_TYPE_ID, {inst->GetSingleWordInOperand(1)}}});
return true;
}
if (kind1 == FloatConstantKind::Zero) {
inst->SetOpcode(SpvOpCopyObject);
inst->SetInOperands(
{{SPV_OPERAND_TYPE_ID, {inst->GetSingleWordInOperand(0)}}});
return true;
}
return false;
};
}
FoldingRule RedundantFMul() {
return [](IRContext*, Instruction* inst,
const std::vector<const analysis::Constant*>& constants) {
assert(inst->opcode() == SpvOpFMul && "Wrong opcode. Should be OpFMul.");
assert(constants.size() == 2);
if (!inst->IsFloatingPointFoldingAllowed()) {
return false;
}
FloatConstantKind kind0 = getFloatConstantKind(constants[0]);
FloatConstantKind kind1 = getFloatConstantKind(constants[1]);
if (kind0 == FloatConstantKind::Zero || kind1 == FloatConstantKind::Zero) {
inst->SetOpcode(SpvOpCopyObject);
inst->SetInOperands({{SPV_OPERAND_TYPE_ID,
{inst->GetSingleWordInOperand(
kind0 == FloatConstantKind::Zero ? 0 : 1)}}});
return true;
}
if (kind0 == FloatConstantKind::One || kind1 == FloatConstantKind::One) {
inst->SetOpcode(SpvOpCopyObject);
inst->SetInOperands({{SPV_OPERAND_TYPE_ID,
{inst->GetSingleWordInOperand(
kind0 == FloatConstantKind::One ? 1 : 0)}}});
return true;
}
return false;
};
}
FoldingRule RedundantFDiv() {
return [](IRContext*, Instruction* inst,
const std::vector<const analysis::Constant*>& constants) {
assert(inst->opcode() == SpvOpFDiv && "Wrong opcode. Should be OpFDiv.");
assert(constants.size() == 2);
if (!inst->IsFloatingPointFoldingAllowed()) {
return false;
}
FloatConstantKind kind0 = getFloatConstantKind(constants[0]);
FloatConstantKind kind1 = getFloatConstantKind(constants[1]);
if (kind0 == FloatConstantKind::Zero) {
inst->SetOpcode(SpvOpCopyObject);
inst->SetInOperands(
{{SPV_OPERAND_TYPE_ID, {inst->GetSingleWordInOperand(0)}}});
return true;
}
if (kind1 == FloatConstantKind::One) {
inst->SetOpcode(SpvOpCopyObject);
inst->SetInOperands(
{{SPV_OPERAND_TYPE_ID, {inst->GetSingleWordInOperand(0)}}});
return true;
}
return false;
};
}
FoldingRule RedundantFMix() {
return [](IRContext* context, Instruction* inst,
const std::vector<const analysis::Constant*>& constants) {
assert(inst->opcode() == SpvOpExtInst &&
"Wrong opcode. Should be OpExtInst.");
if (!inst->IsFloatingPointFoldingAllowed()) {
return false;
}
uint32_t instSetId =
context->get_feature_mgr()->GetExtInstImportId_GLSLstd450();
if (inst->GetSingleWordInOperand(kExtInstSetIdInIdx) == instSetId &&
inst->GetSingleWordInOperand(kExtInstInstructionInIdx) ==
GLSLstd450FMix) {
assert(constants.size() == 5);
FloatConstantKind kind4 = getFloatConstantKind(constants[4]);
if (kind4 == FloatConstantKind::Zero || kind4 == FloatConstantKind::One) {
inst->SetOpcode(SpvOpCopyObject);
inst->SetInOperands(
{{SPV_OPERAND_TYPE_ID,
{inst->GetSingleWordInOperand(kind4 == FloatConstantKind::Zero
? kFMixXIdInIdx
: kFMixYIdInIdx)}}});
return true;
}
}
return false;
};
}
// This rule handles addition of zero for integers.
FoldingRule RedundantIAdd() {
return [](IRContext* context, Instruction* inst,
const std::vector<const analysis::Constant*>& constants) {
assert(inst->opcode() == SpvOpIAdd && "Wrong opcode. Should be OpIAdd.");
uint32_t operand = std::numeric_limits<uint32_t>::max();
const analysis::Type* operand_type = nullptr;
if (constants[0] && constants[0]->IsZero()) {
operand = inst->GetSingleWordInOperand(1);
operand_type = constants[0]->type();
} else if (constants[1] && constants[1]->IsZero()) {
operand = inst->GetSingleWordInOperand(0);
operand_type = constants[1]->type();
}
if (operand != std::numeric_limits<uint32_t>::max()) {
const analysis::Type* inst_type =
context->get_type_mgr()->GetType(inst->type_id());
if (inst_type->IsSame(operand_type)) {
inst->SetOpcode(SpvOpCopyObject);
} else {
inst->SetOpcode(SpvOpBitcast);
}
inst->SetInOperands({{SPV_OPERAND_TYPE_ID, {operand}}});
return true;
}
return false;
};
}
// This rule look for a dot with a constant vector containing a single 1 and
// the rest 0s. This is the same as doing an extract.
FoldingRule DotProductDoingExtract() {
return [](IRContext* context, Instruction* inst,
const std::vector<const analysis::Constant*>& constants) {
assert(inst->opcode() == SpvOpDot && "Wrong opcode. Should be OpDot.");
analysis::ConstantManager* const_mgr = context->get_constant_mgr();
if (!inst->IsFloatingPointFoldingAllowed()) {
return false;
}
for (int i = 0; i < 2; ++i) {
if (!constants[i]) {
continue;
}
const analysis::Vector* vector_type = constants[i]->type()->AsVector();
assert(vector_type && "Inputs to OpDot must be vectors.");
const analysis::Float* element_type =
vector_type->element_type()->AsFloat();
assert(element_type && "Inputs to OpDot must be vectors of floats.");
uint32_t element_width = element_type->width();
if (element_width != 32 && element_width != 64) {
return false;
}
std::vector<const analysis::Constant*> components;
components = constants[i]->GetVectorComponents(const_mgr);
const uint32_t kNotFound = std::numeric_limits<uint32_t>::max();
uint32_t component_with_one = kNotFound;
bool all_others_zero = true;
for (uint32_t j = 0; j < components.size(); ++j) {
const analysis::Constant* element = components[j];
double value =
(element_width == 32 ? element->GetFloat() : element->GetDouble());
if (value == 0.0) {
continue;
} else if (value == 1.0) {
if (component_with_one == kNotFound) {
component_with_one = j;
} else {
component_with_one = kNotFound;
break;
}
} else {
all_others_zero = false;
break;
}
}
if (!all_others_zero || component_with_one == kNotFound) {
continue;
}
std::vector<Operand> operands;
operands.push_back(
{SPV_OPERAND_TYPE_ID, {inst->GetSingleWordInOperand(1u - i)}});
operands.push_back(
{SPV_OPERAND_TYPE_LITERAL_INTEGER, {component_with_one}});
inst->SetOpcode(SpvOpCompositeExtract);
inst->SetInOperands(std::move(operands));
return true;
}
return false;
};
}
// If we are storing an undef, then we can remove the store.
//
// TODO: We can do something similar for OpImageWrite, but checking for volatile
// is complicated. Waiting to see if it is needed.
FoldingRule StoringUndef() {
return [](IRContext* context, Instruction* inst,
const std::vector<const analysis::Constant*>&) {
assert(inst->opcode() == SpvOpStore && "Wrong opcode. Should be OpStore.");
analysis::DefUseManager* def_use_mgr = context->get_def_use_mgr();
// If this is a volatile store, the store cannot be removed.
if (inst->NumInOperands() == 3) {
if (inst->GetSingleWordInOperand(2) & SpvMemoryAccessVolatileMask) {
return false;
}
}
uint32_t object_id = inst->GetSingleWordInOperand(kStoreObjectInIdx);
Instruction* object_inst = def_use_mgr->GetDef(object_id);
if (object_inst->opcode() == SpvOpUndef) {
inst->ToNop();
return true;
}
return false;
};
}
FoldingRule VectorShuffleFeedingShuffle() {
return [](IRContext* context, Instruction* inst,
const std::vector<const analysis::Constant*>&) {
assert(inst->opcode() == SpvOpVectorShuffle &&
"Wrong opcode. Should be OpVectorShuffle.");
analysis::DefUseManager* def_use_mgr = context->get_def_use_mgr();
analysis::TypeManager* type_mgr = context->get_type_mgr();
Instruction* feeding_shuffle_inst =
def_use_mgr->GetDef(inst->GetSingleWordInOperand(0));
analysis::Vector* op0_type =
type_mgr->GetType(feeding_shuffle_inst->type_id())->AsVector();
uint32_t op0_length = op0_type->element_count();
bool feeder_is_op0 = true;
if (feeding_shuffle_inst->opcode() != SpvOpVectorShuffle) {
feeding_shuffle_inst =
def_use_mgr->GetDef(inst->GetSingleWordInOperand(1));
feeder_is_op0 = false;
}
if (feeding_shuffle_inst->opcode() != SpvOpVectorShuffle) {
return false;
}
Instruction* feeder2 =
def_use_mgr->GetDef(feeding_shuffle_inst->GetSingleWordInOperand(0));
analysis::Vector* feeder_op0_type =
type_mgr->GetType(feeder2->type_id())->AsVector();
uint32_t feeder_op0_length = feeder_op0_type->element_count();
uint32_t new_feeder_id = 0;
std::vector<Operand> new_operands;
new_operands.resize(
2, {SPV_OPERAND_TYPE_ID, {0}}); // Place holders for vector operands.
const uint32_t undef_literal = 0xffffffff;
for (uint32_t op = 2; op < inst->NumInOperands(); ++op) {
uint32_t component_index = inst->GetSingleWordInOperand(op);
// Do not interpret the undefined value literal as coming from operand 1.
if (component_index != undef_literal &&
feeder_is_op0 == (component_index < op0_length)) {
// This component comes from the feeding_shuffle_inst. Update
// |component_index| to be the index into the operand of the feeder.
// Adjust component_index to get the index into the operands of the
// feeding_shuffle_inst.
if (component_index >= op0_length) {
component_index -= op0_length;
}
component_index =
feeding_shuffle_inst->GetSingleWordInOperand(component_index + 2);
// Check if we are using a component from the first or second operand of
// the feeding instruction.
if (component_index < feeder_op0_length) {
if (new_feeder_id == 0) {
// First time through, save the id of the operand the element comes
// from.
new_feeder_id = feeding_shuffle_inst->GetSingleWordInOperand(0);
} else if (new_feeder_id !=
feeding_shuffle_inst->GetSingleWordInOperand(0)) {
// We need both elements of the feeding_shuffle_inst, so we cannot
// fold.
return false;
}
} else {
if (new_feeder_id == 0) {
// First time through, save the id of the operand the element comes
// from.
new_feeder_id = feeding_shuffle_inst->GetSingleWordInOperand(1);
} else if (new_feeder_id !=
feeding_shuffle_inst->GetSingleWordInOperand(1)) {
// We need both elements of the feeding_shuffle_inst, so we cannot
// fold.
return false;
}
component_index -= feeder_op0_length;
}
if (!feeder_is_op0) {
component_index += op0_length;
}
}
new_operands.push_back(
{SPV_OPERAND_TYPE_LITERAL_INTEGER, {component_index}});
}
if (new_feeder_id == 0) {
analysis::ConstantManager* const_mgr = context->get_constant_mgr();
const analysis::Type* type =
type_mgr->GetType(feeding_shuffle_inst->type_id());
const analysis::Constant* null_const = const_mgr->GetConstant(type, {});
new_feeder_id =
const_mgr->GetDefiningInstruction(null_const, 0)->result_id();
}
if (feeder_is_op0) {
// If the size of the first vector operand changed then the indices
// referring to the second operand need to be adjusted.
Instruction* new_feeder_inst = def_use_mgr->GetDef(new_feeder_id);
analysis::Type* new_feeder_type =
type_mgr->GetType(new_feeder_inst->type_id());
uint32_t new_op0_size = new_feeder_type->AsVector()->element_count();
int32_t adjustment = op0_length - new_op0_size;
if (adjustment != 0) {
for (uint32_t i = 2; i < new_operands.size(); i++) {
if (inst->GetSingleWordInOperand(i) >= op0_length) {
new_operands[i].words[0] -= adjustment;
}
}
}
new_operands[0].words[0] = new_feeder_id;
new_operands[1] = inst->GetInOperand(1);
} else {
new_operands[1].words[0] = new_feeder_id;
new_operands[0] = inst->GetInOperand(0);
}
inst->SetInOperands(std::move(new_operands));
return true;
};
}
// Removes duplicate ids from the interface list of an OpEntryPoint
// instruction.
FoldingRule RemoveRedundantOperands() {
return [](IRContext*, Instruction* inst,
const std::vector<const analysis::Constant*>&) {
assert(inst->opcode() == SpvOpEntryPoint &&
"Wrong opcode. Should be OpEntryPoint.");
bool has_redundant_operand = false;
std::unordered_set<uint32_t> seen_operands;
std::vector<Operand> new_operands;
new_operands.emplace_back(inst->GetOperand(0));
new_operands.emplace_back(inst->GetOperand(1));
new_operands.emplace_back(inst->GetOperand(2));
for (uint32_t i = 3; i < inst->NumOperands(); ++i) {
if (seen_operands.insert(inst->GetSingleWordOperand(i)).second) {
new_operands.emplace_back(inst->GetOperand(i));
} else {
has_redundant_operand = true;
}
}
if (!has_redundant_operand) {
return false;
}
inst->SetInOperands(std::move(new_operands));
return true;
};
}
// If an image instruction's operand is a constant, updates the image operand
// flag from Offset to ConstOffset.
FoldingRule UpdateImageOperands() {
return [](IRContext*, Instruction* inst,
const std::vector<const analysis::Constant*>& constants) {
const auto opcode = inst->opcode();
(void)opcode;
assert((opcode == SpvOpImageSampleImplicitLod ||
opcode == SpvOpImageSampleExplicitLod ||
opcode == SpvOpImageSampleDrefImplicitLod ||
opcode == SpvOpImageSampleDrefExplicitLod ||
opcode == SpvOpImageSampleProjImplicitLod ||
opcode == SpvOpImageSampleProjExplicitLod ||
opcode == SpvOpImageSampleProjDrefImplicitLod ||
opcode == SpvOpImageSampleProjDrefExplicitLod ||
opcode == SpvOpImageFetch || opcode == SpvOpImageGather ||
opcode == SpvOpImageDrefGather || opcode == SpvOpImageRead ||
opcode == SpvOpImageWrite ||
opcode == SpvOpImageSparseSampleImplicitLod ||
opcode == SpvOpImageSparseSampleExplicitLod ||
opcode == SpvOpImageSparseSampleDrefImplicitLod ||
opcode == SpvOpImageSparseSampleDrefExplicitLod ||
opcode == SpvOpImageSparseSampleProjImplicitLod ||
opcode == SpvOpImageSparseSampleProjExplicitLod ||
opcode == SpvOpImageSparseSampleProjDrefImplicitLod ||
opcode == SpvOpImageSparseSampleProjDrefExplicitLod ||
opcode == SpvOpImageSparseFetch ||
opcode == SpvOpImageSparseGather ||
opcode == SpvOpImageSparseDrefGather ||
opcode == SpvOpImageSparseRead) &&
"Wrong opcode. Should be an image instruction.");
int32_t operand_index = ImageOperandsMaskInOperandIndex(inst);
if (operand_index >= 0) {
auto image_operands = inst->GetSingleWordInOperand(operand_index);
if (image_operands & SpvImageOperandsOffsetMask) {
uint32_t offset_operand_index = operand_index + 1;
if (image_operands & SpvImageOperandsBiasMask) offset_operand_index++;
if (image_operands & SpvImageOperandsLodMask) offset_operand_index++;
if (image_operands & SpvImageOperandsGradMask)
offset_operand_index += 2;
assert(((image_operands & SpvImageOperandsConstOffsetMask) == 0) &&
"Offset and ConstOffset may not be used together");
if (offset_operand_index < inst->NumOperands()) {
if (constants[offset_operand_index]) {
image_operands = image_operands | SpvImageOperandsConstOffsetMask;
image_operands = image_operands & ~SpvImageOperandsOffsetMask;
inst->SetInOperand(operand_index, {image_operands});
return true;
}
}
}
}
return false;
};
}
} // namespace
void FoldingRules::AddFoldingRules() {
// Add all folding rules to the list for the opcodes to which they apply.
// Note that the order in which rules are added to the list matters. If a rule
// applies to the instruction, the rest of the rules will not be attempted.
// Take that into consideration.
rules_[SpvOpBitcast].push_back(BitCastScalarOrVector());
rules_[SpvOpCompositeConstruct].push_back(CompositeExtractFeedingConstruct);
rules_[SpvOpCompositeExtract].push_back(InsertFeedingExtract());
rules_[SpvOpCompositeExtract].push_back(CompositeConstructFeedingExtract());
rules_[SpvOpCompositeExtract].push_back(VectorShuffleFeedingExtract());
rules_[SpvOpCompositeExtract].push_back(FMixFeedingExtract());
rules_[SpvOpDot].push_back(DotProductDoingExtract());
rules_[SpvOpEntryPoint].push_back(RemoveRedundantOperands());
rules_[SpvOpFAdd].push_back(RedundantFAdd());
rules_[SpvOpFAdd].push_back(MergeAddNegateArithmetic());
rules_[SpvOpFAdd].push_back(MergeAddAddArithmetic());
rules_[SpvOpFAdd].push_back(MergeAddSubArithmetic());
rules_[SpvOpFAdd].push_back(MergeGenericAddSubArithmetic());
rules_[SpvOpFAdd].push_back(FactorAddMuls());
rules_[SpvOpFDiv].push_back(RedundantFDiv());
rules_[SpvOpFDiv].push_back(ReciprocalFDiv());
rules_[SpvOpFDiv].push_back(MergeDivDivArithmetic());
rules_[SpvOpFDiv].push_back(MergeDivMulArithmetic());
rules_[SpvOpFDiv].push_back(MergeDivNegateArithmetic());
rules_[SpvOpFMul].push_back(RedundantFMul());
rules_[SpvOpFMul].push_back(MergeMulMulArithmetic());
rules_[SpvOpFMul].push_back(MergeMulDivArithmetic());
rules_[SpvOpFMul].push_back(MergeMulNegateArithmetic());
rules_[SpvOpFNegate].push_back(MergeNegateArithmetic());
rules_[SpvOpFNegate].push_back(MergeNegateAddSubArithmetic());
rules_[SpvOpFNegate].push_back(MergeNegateMulDivArithmetic());
rules_[SpvOpFSub].push_back(RedundantFSub());
rules_[SpvOpFSub].push_back(MergeSubNegateArithmetic());
rules_[SpvOpFSub].push_back(MergeSubAddArithmetic());
rules_[SpvOpFSub].push_back(MergeSubSubArithmetic());
rules_[SpvOpIAdd].push_back(RedundantIAdd());
rules_[SpvOpIAdd].push_back(MergeAddNegateArithmetic());
rules_[SpvOpIAdd].push_back(MergeAddAddArithmetic());
rules_[SpvOpIAdd].push_back(MergeAddSubArithmetic());
rules_[SpvOpIAdd].push_back(MergeGenericAddSubArithmetic());
rules_[SpvOpIAdd].push_back(FactorAddMuls());
rules_[SpvOpIMul].push_back(IntMultipleBy1());
rules_[SpvOpIMul].push_back(MergeMulMulArithmetic());
rules_[SpvOpIMul].push_back(MergeMulNegateArithmetic());
rules_[SpvOpISub].push_back(MergeSubNegateArithmetic());
rules_[SpvOpISub].push_back(MergeSubAddArithmetic());
rules_[SpvOpISub].push_back(MergeSubSubArithmetic());
rules_[SpvOpPhi].push_back(RedundantPhi());
rules_[SpvOpSDiv].push_back(MergeDivNegateArithmetic());
rules_[SpvOpSNegate].push_back(MergeNegateArithmetic());
rules_[SpvOpSNegate].push_back(MergeNegateMulDivArithmetic());
rules_[SpvOpSNegate].push_back(MergeNegateAddSubArithmetic());
rules_[SpvOpSelect].push_back(RedundantSelect());
rules_[SpvOpStore].push_back(StoringUndef());
rules_[SpvOpVectorShuffle].push_back(VectorShuffleFeedingShuffle());
rules_[SpvOpImageSampleImplicitLod].push_back(UpdateImageOperands());
rules_[SpvOpImageSampleExplicitLod].push_back(UpdateImageOperands());
rules_[SpvOpImageSampleDrefImplicitLod].push_back(UpdateImageOperands());
rules_[SpvOpImageSampleDrefExplicitLod].push_back(UpdateImageOperands());
rules_[SpvOpImageSampleProjImplicitLod].push_back(UpdateImageOperands());
rules_[SpvOpImageSampleProjExplicitLod].push_back(UpdateImageOperands());
rules_[SpvOpImageSampleProjDrefImplicitLod].push_back(UpdateImageOperands());
rules_[SpvOpImageSampleProjDrefExplicitLod].push_back(UpdateImageOperands());
rules_[SpvOpImageFetch].push_back(UpdateImageOperands());
rules_[SpvOpImageGather].push_back(UpdateImageOperands());
rules_[SpvOpImageDrefGather].push_back(UpdateImageOperands());
rules_[SpvOpImageRead].push_back(UpdateImageOperands());
rules_[SpvOpImageWrite].push_back(UpdateImageOperands());
rules_[SpvOpImageSparseSampleImplicitLod].push_back(UpdateImageOperands());
rules_[SpvOpImageSparseSampleExplicitLod].push_back(UpdateImageOperands());
rules_[SpvOpImageSparseSampleDrefImplicitLod].push_back(
UpdateImageOperands());
rules_[SpvOpImageSparseSampleDrefExplicitLod].push_back(
UpdateImageOperands());
rules_[SpvOpImageSparseSampleProjImplicitLod].push_back(
UpdateImageOperands());
rules_[SpvOpImageSparseSampleProjExplicitLod].push_back(
UpdateImageOperands());
rules_[SpvOpImageSparseSampleProjDrefImplicitLod].push_back(
UpdateImageOperands());
rules_[SpvOpImageSparseSampleProjDrefExplicitLod].push_back(
UpdateImageOperands());
rules_[SpvOpImageSparseFetch].push_back(UpdateImageOperands());
rules_[SpvOpImageSparseGather].push_back(UpdateImageOperands());
rules_[SpvOpImageSparseDrefGather].push_back(UpdateImageOperands());
rules_[SpvOpImageSparseRead].push_back(UpdateImageOperands());
FeatureManager* feature_manager = context_->get_feature_mgr();
// Add rules for GLSLstd450
uint32_t ext_inst_glslstd450_id =
feature_manager->GetExtInstImportId_GLSLstd450();
if (ext_inst_glslstd450_id != 0) {
ext_rules_[{ext_inst_glslstd450_id, GLSLstd450FMix}].push_back(
RedundantFMix());
}
}
} // namespace opt
} // namespace spvtools
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