diff options
| -rw-r--r-- | include/llvm/Target/TargetInstrInfo.h | 10 | ||||
| -rw-r--r-- | lib/CodeGen/TargetInstrInfoImpl.cpp | 22 |
2 files changed, 31 insertions, 1 deletions
diff --git a/include/llvm/Target/TargetInstrInfo.h b/include/llvm/Target/TargetInstrInfo.h index f9b361f..7526087 100644 --- a/include/llvm/Target/TargetInstrInfo.h +++ b/include/llvm/Target/TargetInstrInfo.h @@ -149,6 +149,14 @@ public: /// virtual MachineInstr *commuteInstruction(MachineInstr *MI) const = 0; + /// CommuteChangesDestination - Return true if commuting the specified + /// instruction will also changes the destination operand. Also return the + /// current operand index of the would be new destination register by + /// reference. This can happen when the commutable instruction is also a + /// two-address instruction. + virtual bool CommuteChangesDestination(MachineInstr *MI, + unsigned &OpIdx) const = 0; + /// AnalyzeBranch - Analyze the branching code at the end of MBB, returning /// true if it cannot be understood (e.g. it's a switch dispatch or isn't /// implemented for a target). Upon success, this returns false and returns @@ -384,6 +392,8 @@ protected: : TargetInstrInfo(desc, NumOpcodes) {} public: virtual MachineInstr *commuteInstruction(MachineInstr *MI) const; + virtual bool CommuteChangesDestination(MachineInstr *MI, + unsigned &OpIdx) const; virtual bool PredicateInstruction(MachineInstr *MI, const std::vector<MachineOperand> &Pred) const; diff --git a/lib/CodeGen/TargetInstrInfoImpl.cpp b/lib/CodeGen/TargetInstrInfoImpl.cpp index 4f6c123..ceec82b 100644 --- a/lib/CodeGen/TargetInstrInfoImpl.cpp +++ b/lib/CodeGen/TargetInstrInfoImpl.cpp @@ -39,8 +39,28 @@ MachineInstr *TargetInstrInfoImpl::commuteInstruction(MachineInstr *MI) const { return MI; } +/// CommuteChangesDestination - Return true if commuting the specified +/// instruction will also changes the destination operand. Also return the +/// current operand index of the would be new destination register by +/// reference. This can happen when the commutable instruction is also a +/// two-address instruction. +bool TargetInstrInfoImpl::CommuteChangesDestination(MachineInstr *MI, + unsigned &OpIdx) const{ + assert(MI->getOperand(1).isRegister() && MI->getOperand(2).isRegister() && + "This only knows how to commute register operands so far"); + if (MI->getOperand(0).getReg() == MI->getOperand(1).getReg()) { + // Must be two address instruction! + assert(MI->getDesc().getOperandConstraint(0, TOI::TIED_TO) && + "Expecting a two-address instruction!"); + OpIdx = 2; + return true; + } + return false; +} + + bool TargetInstrInfoImpl::PredicateInstruction(MachineInstr *MI, - const std::vector<MachineOperand> &Pred) const { + const std::vector<MachineOperand> &Pred) const { bool MadeChange = false; const TargetInstrDesc &TID = MI->getDesc(); if (!TID.isPredicable()) |