diff options
| -rw-r--r-- | backend/lib/Target/RISCV/RISCVCodeGen.cpp | 18 | ||||
| -rw-r--r-- | backend/unittests/Target/RISCVCodeGenTest.cpp | 23 |
2 files changed, 38 insertions, 3 deletions
diff --git a/backend/lib/Target/RISCV/RISCVCodeGen.cpp b/backend/lib/Target/RISCV/RISCVCodeGen.cpp index 2f7eca9..e790edf 100644 --- a/backend/lib/Target/RISCV/RISCVCodeGen.cpp +++ b/backend/lib/Target/RISCV/RISCVCodeGen.cpp @@ -128,6 +128,7 @@ extendIntegerImmediate(const IntegerImmediate &Value, std::uint32_t DestinationW "RISC-V constant extension requires virtual-register operands"); } const Register SourceRegister = *Source; + const Register DestinationRegister = *Destination; const MachineOperand *SourceDefinition = Function.registerInfo().getUniqueVRegDef(SourceRegister); const MachineInstr *SourceDef = SourceDefinition == nullptr ? nullptr : SourceDefinition->parent(); if (SourceDef == nullptr || SourceDef->opcode() != opcode(GenericOpcode::G_CONSTANT)) @@ -150,6 +151,23 @@ extendIntegerImmediate(const IntegerImmediate &Value, std::uint32_t DestinationW if (!Extended) return std::unexpected(Extended.error()); + if (Function.registerInfo().hasOneUse(SourceRegister)) { + MachineInstr *Def = const_cast<MachineInstr *>(SourceDef); + if (auto Replaced = Def->operandAt(0)->setRegister(DestinationRegister); !Replaced) + return std::unexpected(Replaced.error()); + auto Erased = Def->eraseOperand(1); + if (!Erased) + return std::unexpected(Erased.error()); + auto Added = Def->addOperand(MachineOperand::integerImmediate(std::move(*Extended))); + if (!Added) + return std::unexpected(Added.error()); + MachineBasicBlock *Parent = Instruction.parent(); + if (Parent == nullptr) + return makeUnexpected(ErrorCode::VerificationError, + "RISC-V constant extension is detached during folding"); + return Parent->removeInstruction(Instruction); + } + auto SetOpcode = Instruction.setOpcode(opcode(GenericOpcode::G_CONSTANT)); if (!SetOpcode) return std::unexpected(SetOpcode.error()); diff --git a/backend/unittests/Target/RISCVCodeGenTest.cpp b/backend/unittests/Target/RISCVCodeGenTest.cpp index 9665373..40f84f2 100644 --- a/backend/unittests/Target/RISCVCodeGenTest.cpp +++ b/backend/unittests/Target/RISCVCodeGenTest.cpp @@ -1090,11 +1090,16 @@ void testIntegerCompareReusesConstantExtension(TestContext &Context) { return; auto Constant = Builder.buildInstr(rcc::opcode(rcc::GenericOpcode::G_CONSTANT)); if (!Constant || !Constant->addDef(*Right) || - !Constant->addIntegerImmediate(std::move(*Immediate)) || !Constant->build()) + !Constant->addIntegerImmediate(std::move(*Immediate))) + return; + auto BuiltConstant = Constant->build(); + if (!BuiltConstant) return; auto Extension = Builder.buildInstr(rcc::opcode(rcc::GenericOpcode::G_ANYEXT)); - if (!Extension || !Extension->addDef(*WideRight) || !Extension->addUse(*Right) || - !Extension->build()) + if (!Extension || !Extension->addDef(*WideRight) || !Extension->addUse(*Right)) + return; + auto BuiltExtension = Extension->build(); + if (!BuiltExtension) return; auto Action = rcc::riscv::legalizerInfo().classify(*Compare, *Function, *Target); @@ -1107,6 +1112,18 @@ void testIntegerCompareReusesConstantExtension(TestContext &Context) { "RV64 integer comparison legalization must reuse an existing constant extension"); Context.expect(Function->registerInfo().verifyDefUseChains().has_value(), "integer comparison extension reuse must preserve exact def-use chains"); + + auto ExtensionAction = rcc::riscv::legalizerInfo().classify(**BuiltExtension, *Function, *Target); + auto Folded = ExtensionAction ? rcc::riscv::legalizerInfo().lower(**BuiltExtension, *Function, + *Target, *ExtensionAction) + : rcc::Expected<void>(std::unexpected(ExtensionAction.error())); + const rcc::Register *FoldedResult = (*BuiltConstant)->operandAt(0)->getIf<rcc::Register>(); + Context.expect(ExtensionAction && *ExtensionAction == rcc::LegalizationAction::Custom && Folded && + (*BuiltExtension)->parent() == nullptr && FoldedResult != nullptr && + *FoldedResult == *WideRight && + Function->firstBlock()->firstInstruction() == *BuiltConstant && + Function->registerInfo().verifyDefUseChains(), + "single-use constant extension folding must preserve the source layout position"); } void testAtomicSelection(TestContext &Context) { |