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https://github.com/KhronosGroup/SPIRV-Tools
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Add folding rule to generate Fma instructions (#4783)
Adding Fma instruction can speed up the code. This was requested by swiftshader, so they do not have to do this analysis themselves. It can also help reduce the code size, and the work the ICD compilers have to do.
This commit is contained in:
Steven Perron
GitHub
parent
cb96abbf7a
commit
2b2b0282af
@ -1430,6 +1430,64 @@ FoldingRule FactorAddMuls() {
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};
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}
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// Replaces |inst| inplace with an FMA instruction |(x*y)+a|.
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void ReplaceWithFma(Instruction* inst, uint32_t x, uint32_t y, uint32_t a) {
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uint32_t ext =
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inst->context()->get_feature_mgr()->GetExtInstImportId_GLSLstd450();
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if (ext == 0) {
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inst->context()->AddExtInstImport("GLSL.std.450");
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ext = inst->context()->get_feature_mgr()->GetExtInstImportId_GLSLstd450();
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assert(ext != 0 &&
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"Could not add the GLSL.std.450 extended instruction set");
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}
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std::vector<Operand> operands;
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operands.push_back({SPV_OPERAND_TYPE_ID, {ext}});
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operands.push_back({SPV_OPERAND_TYPE_LITERAL_INTEGER, {GLSLstd450Fma}});
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operands.push_back({SPV_OPERAND_TYPE_ID, {x}});
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operands.push_back({SPV_OPERAND_TYPE_ID, {y}});
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operands.push_back({SPV_OPERAND_TYPE_ID, {a}});
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inst->SetOpcode(SpvOpExtInst);
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inst->SetInOperands(std::move(operands));
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}
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// Folds a multiple and add into an Fma.
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//
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// Cases:
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// (x * y) + a = Fma x y a
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// a + (x * y) = Fma x y a
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bool MergeMulAddArithmetic(IRContext* context, Instruction* inst,
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const std::vector<const analysis::Constant*>&) {
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assert(inst->opcode() == SpvOpFAdd);
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if (!inst->IsFloatingPointFoldingAllowed()) {
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return false;
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}
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analysis::DefUseManager* def_use_mgr = context->get_def_use_mgr();
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for (int i = 0; i < 2; i++) {
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uint32_t op_id = inst->GetSingleWordInOperand(i);
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Instruction* op_inst = def_use_mgr->GetDef(op_id);
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if (op_inst->opcode() != SpvOpFMul) {
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continue;
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}
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if (!op_inst->IsFloatingPointFoldingAllowed()) {
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continue;
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}
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uint32_t x = op_inst->GetSingleWordInOperand(0);
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uint32_t y = op_inst->GetSingleWordInOperand(1);
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uint32_t a = inst->GetSingleWordInOperand((i + 1) % 2);
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ReplaceWithFma(inst, x, y, a);
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return true;
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}
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return false;
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}
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FoldingRule IntMultipleBy1() {
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return [](IRContext*, Instruction* inst,
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const std::vector<const analysis::Constant*>& constants) {
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@ -2543,6 +2601,7 @@ void FoldingRules::AddFoldingRules() {
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rules_[SpvOpFAdd].push_back(MergeAddSubArithmetic());
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rules_[SpvOpFAdd].push_back(MergeGenericAddSubArithmetic());
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rules_[SpvOpFAdd].push_back(FactorAddMuls());
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rules_[SpvOpFAdd].push_back(MergeMulAddArithmetic);
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rules_[SpvOpFDiv].push_back(RedundantFDiv());
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rules_[SpvOpFDiv].push_back(ReciprocalFDiv());
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@ -7108,6 +7108,214 @@ INSTANTIATE_TEST_SUITE_P(VectorShuffleMatchingTest, MatchingInstructionFoldingTe
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3, true)
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));
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INSTANTIATE_TEST_SUITE_P(FmaGenerationMatchingTest, MatchingInstructionFoldingTest,
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::testing::Values(
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// Test case 0: (x * y) + a = Fma(x, y, a)
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InstructionFoldingCase<bool>(
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Header() +
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"; CHECK: [[ext:%\\w+]] = OpExtInstImport \"GLSL.std.450\"\n" +
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"; CHECK: OpFunction\n" +
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"; CHECK: [[x:%\\w+]] = OpVariable {{%\\w+}} Function\n" +
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"; CHECK: [[y:%\\w+]] = OpVariable {{%\\w+}} Function\n" +
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"; CHECK: [[a:%\\w+]] = OpVariable {{%\\w+}} Function\n" +
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"; CHECK: [[lx:%\\w+]] = OpLoad {{%\\w+}} [[x]]\n" +
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"; CHECK: [[ly:%\\w+]] = OpLoad {{%\\w+}} [[y]]\n" +
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"; CHECK: [[la:%\\w+]] = OpLoad {{%\\w+}} [[a]]\n" +
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"; CHECK: [[fma:%\\w+]] = OpExtInst {{%\\w+}} [[ext]] Fma [[lx]] [[ly]] [[la]]\n" +
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"; CHECK: OpStore {{%\\w+}} [[fma]]\n" +
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"%main = OpFunction %void None %void_func\n" +
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"%main_lab = OpLabel\n" +
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"%x = OpVariable %_ptr_float Function\n" +
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"%y = OpVariable %_ptr_float Function\n" +
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"%a = OpVariable %_ptr_float Function\n" +
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"%lx = OpLoad %float %x\n" +
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"%ly = OpLoad %float %y\n" +
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"%mul = OpFMul %float %lx %ly\n" +
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"%la = OpLoad %float %a\n" +
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"%3 = OpFAdd %float %mul %la\n" +
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"OpStore %a %3\n" +
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"OpReturn\n" +
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"OpFunctionEnd",
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3, true),
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// Test case 1: a + (x * y) = Fma(x, y, a)
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InstructionFoldingCase<bool>(
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Header() +
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"; CHECK: [[ext:%\\w+]] = OpExtInstImport \"GLSL.std.450\"\n" +
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"; CHECK: OpFunction\n" +
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"; CHECK: [[x:%\\w+]] = OpVariable {{%\\w+}} Function\n" +
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"; CHECK: [[y:%\\w+]] = OpVariable {{%\\w+}} Function\n" +
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"; CHECK: [[a:%\\w+]] = OpVariable {{%\\w+}} Function\n" +
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"; CHECK: [[lx:%\\w+]] = OpLoad {{%\\w+}} [[x]]\n" +
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"; CHECK: [[ly:%\\w+]] = OpLoad {{%\\w+}} [[y]]\n" +
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"; CHECK: [[la:%\\w+]] = OpLoad {{%\\w+}} [[a]]\n" +
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"; CHECK: [[fma:%\\w+]] = OpExtInst {{%\\w+}} [[ext]] Fma [[lx]] [[ly]] [[la]]\n" +
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"; CHECK: OpStore {{%\\w+}} [[fma]]\n" +
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"%main = OpFunction %void None %void_func\n" +
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"%main_lab = OpLabel\n" +
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"%x = OpVariable %_ptr_float Function\n" +
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"%y = OpVariable %_ptr_float Function\n" +
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"%a = OpVariable %_ptr_float Function\n" +
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"%lx = OpLoad %float %x\n" +
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"%ly = OpLoad %float %y\n" +
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"%mul = OpFMul %float %lx %ly\n" +
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"%la = OpLoad %float %a\n" +
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"%3 = OpFAdd %float %la %mul\n" +
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"OpStore %a %3\n" +
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"OpReturn\n" +
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"OpFunctionEnd",
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3, true),
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// Test case 2: (x * y) + a = Fma(x, y, a) with vectors
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InstructionFoldingCase<bool>(
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Header() +
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"; CHECK: [[ext:%\\w+]] = OpExtInstImport \"GLSL.std.450\"\n" +
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"; CHECK: OpFunction\n" +
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"; CHECK: [[x:%\\w+]] = OpVariable {{%\\w+}} Function\n" +
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"; CHECK: [[y:%\\w+]] = OpVariable {{%\\w+}} Function\n" +
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"; CHECK: [[a:%\\w+]] = OpVariable {{%\\w+}} Function\n" +
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"; CHECK: [[lx:%\\w+]] = OpLoad {{%\\w+}} [[x]]\n" +
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"; CHECK: [[ly:%\\w+]] = OpLoad {{%\\w+}} [[y]]\n" +
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"; CHECK: [[la:%\\w+]] = OpLoad {{%\\w+}} [[a]]\n" +
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"; CHECK: [[fma:%\\w+]] = OpExtInst {{%\\w+}} [[ext]] Fma [[lx]] [[ly]] [[la]]\n" +
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"; CHECK: OpStore {{%\\w+}} [[fma]]\n" +
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"%main = OpFunction %void None %void_func\n" +
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"%main_lab = OpLabel\n" +
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"%x = OpVariable %_ptr_v4float Function\n" +
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"%y = OpVariable %_ptr_v4float Function\n" +
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"%a = OpVariable %_ptr_v4float Function\n" +
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"%lx = OpLoad %v4float %x\n" +
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"%ly = OpLoad %v4float %y\n" +
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"%mul = OpFMul %v4float %lx %ly\n" +
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"%la = OpLoad %v4float %a\n" +
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"%3 = OpFAdd %v4float %mul %la\n" +
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"OpStore %a %3\n" +
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"OpReturn\n" +
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"OpFunctionEnd",
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3, true),
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// Test case 3: a + (x * y) = Fma(x, y, a) with vectors
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InstructionFoldingCase<bool>(
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Header() +
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"; CHECK: [[ext:%\\w+]] = OpExtInstImport \"GLSL.std.450\"\n" +
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"; CHECK: OpFunction\n" +
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"; CHECK: [[x:%\\w+]] = OpVariable {{%\\w+}} Function\n" +
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"; CHECK: [[y:%\\w+]] = OpVariable {{%\\w+}} Function\n" +
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"; CHECK: [[a:%\\w+]] = OpVariable {{%\\w+}} Function\n" +
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"; CHECK: [[lx:%\\w+]] = OpLoad {{%\\w+}} [[x]]\n" +
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"; CHECK: [[ly:%\\w+]] = OpLoad {{%\\w+}} [[y]]\n" +
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"; CHECK: [[la:%\\w+]] = OpLoad {{%\\w+}} [[a]]\n" +
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"; CHECK: [[fma:%\\w+]] = OpExtInst {{%\\w+}} [[ext]] Fma [[lx]] [[ly]] [[la]]\n" +
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"; CHECK: OpStore {{%\\w+}} [[fma]]\n" +
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"%main = OpFunction %void None %void_func\n" +
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"%main_lab = OpLabel\n" +
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"%x = OpVariable %_ptr_float Function\n" +
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"%y = OpVariable %_ptr_float Function\n" +
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"%a = OpVariable %_ptr_float Function\n" +
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"%lx = OpLoad %float %x\n" +
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"%ly = OpLoad %float %y\n" +
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"%mul = OpFMul %float %lx %ly\n" +
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"%la = OpLoad %float %a\n" +
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"%3 = OpFAdd %float %la %mul\n" +
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"OpStore %a %3\n" +
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"OpReturn\n" +
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"OpFunctionEnd",
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3, true),
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// Test 5: that the OpExtInstImport instruction is generated if it is missing.
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InstructionFoldingCase<bool>(
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std::string() +
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"; CHECK: [[ext:%\\w+]] = OpExtInstImport \"GLSL.std.450\"\n" +
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"; CHECK: OpFunction\n" +
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"; CHECK: [[x:%\\w+]] = OpVariable {{%\\w+}} Function\n" +
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"; CHECK: [[y:%\\w+]] = OpVariable {{%\\w+}} Function\n" +
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"; CHECK: [[a:%\\w+]] = OpVariable {{%\\w+}} Function\n" +
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"; CHECK: [[lx:%\\w+]] = OpLoad {{%\\w+}} [[x]]\n" +
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"; CHECK: [[ly:%\\w+]] = OpLoad {{%\\w+}} [[y]]\n" +
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"; CHECK: [[la:%\\w+]] = OpLoad {{%\\w+}} [[a]]\n" +
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"; CHECK: [[fma:%\\w+]] = OpExtInst {{%\\w+}} [[ext]] Fma [[lx]] [[ly]] [[la]]\n" +
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"; CHECK: OpStore {{%\\w+}} [[fma]]\n" +
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"OpCapability Shader\n" +
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"OpMemoryModel Logical GLSL450\n" +
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"OpEntryPoint Fragment %main \"main\"\n" +
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"OpExecutionMode %main OriginUpperLeft\n" +
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"OpSource GLSL 140\n" +
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"OpName %main \"main\"\n" +
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"%void = OpTypeVoid\n" +
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"%void_func = OpTypeFunction %void\n" +
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"%bool = OpTypeBool\n" +
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"%float = OpTypeFloat 32\n" +
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"%_ptr_float = OpTypePointer Function %float\n" +
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"%main = OpFunction %void None %void_func\n" +
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"%main_lab = OpLabel\n" +
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"%x = OpVariable %_ptr_float Function\n" +
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"%y = OpVariable %_ptr_float Function\n" +
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"%a = OpVariable %_ptr_float Function\n" +
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"%lx = OpLoad %float %x\n" +
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"%ly = OpLoad %float %y\n" +
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"%mul = OpFMul %float %lx %ly\n" +
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"%la = OpLoad %float %a\n" +
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"%3 = OpFAdd %float %mul %la\n" +
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"OpStore %a %3\n" +
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"OpReturn\n" +
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"OpFunctionEnd",
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3, true),
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// Test 5: Don't fold if the multiple is marked no contract.
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InstructionFoldingCase<bool>(
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std::string() +
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"OpCapability Shader\n" +
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"OpMemoryModel Logical GLSL450\n" +
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"OpEntryPoint Fragment %main \"main\"\n" +
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"OpExecutionMode %main OriginUpperLeft\n" +
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"OpSource GLSL 140\n" +
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"OpName %main \"main\"\n" +
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"OpDecorate %mul NoContraction\n" +
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"%void = OpTypeVoid\n" +
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"%void_func = OpTypeFunction %void\n" +
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"%bool = OpTypeBool\n" +
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"%float = OpTypeFloat 32\n" +
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"%_ptr_float = OpTypePointer Function %float\n" +
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"%main = OpFunction %void None %void_func\n" +
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"%main_lab = OpLabel\n" +
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"%x = OpVariable %_ptr_float Function\n" +
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"%y = OpVariable %_ptr_float Function\n" +
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"%a = OpVariable %_ptr_float Function\n" +
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"%lx = OpLoad %float %x\n" +
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"%ly = OpLoad %float %y\n" +
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"%mul = OpFMul %float %lx %ly\n" +
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"%la = OpLoad %float %a\n" +
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"%3 = OpFAdd %float %mul %la\n" +
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"OpStore %a %3\n" +
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"OpReturn\n" +
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"OpFunctionEnd",
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3, false),
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// Test 6: Don't fold if the add is marked no contract.
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InstructionFoldingCase<bool>(
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std::string() +
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"OpCapability Shader\n" +
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"OpMemoryModel Logical GLSL450\n" +
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"OpEntryPoint Fragment %main \"main\"\n" +
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"OpExecutionMode %main OriginUpperLeft\n" +
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"OpSource GLSL 140\n" +
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"OpName %main \"main\"\n" +
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"OpDecorate %3 NoContraction\n" +
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"%void = OpTypeVoid\n" +
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"%void_func = OpTypeFunction %void\n" +
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"%bool = OpTypeBool\n" +
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"%float = OpTypeFloat 32\n" +
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"%_ptr_float = OpTypePointer Function %float\n" +
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"%main = OpFunction %void None %void_func\n" +
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"%main_lab = OpLabel\n" +
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"%x = OpVariable %_ptr_float Function\n" +
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"%y = OpVariable %_ptr_float Function\n" +
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"%a = OpVariable %_ptr_float Function\n" +
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"%lx = OpLoad %float %x\n" +
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"%ly = OpLoad %float %y\n" +
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"%mul = OpFMul %float %lx %ly\n" +
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"%la = OpLoad %float %a\n" +
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"%3 = OpFAdd %float %mul %la\n" +
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"OpStore %a %3\n" +
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"OpReturn\n" +
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"OpFunctionEnd",
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3, false)
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));
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using MatchingInstructionWithNoResultFoldingTest =
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::testing::TestWithParam<InstructionFoldingCase<bool>>;
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