From df3b99381f1c211071cc1daf0cc297666877bbcb Mon Sep 17 00:00:00 2001 From: Evan Cheng Date: Wed, 27 Aug 2008 20:33:50 +0000 Subject: Refactor isSafeToReMat out of 2addr pass. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@55430 91177308-0d34-0410-b5e6-96231b3b80d8 --- lib/CodeGen/MachineInstr.cpp | 25 +++++++++++++++++++++++++ 1 file changed, 25 insertions(+) (limited to 'lib/CodeGen/MachineInstr.cpp') diff --git a/lib/CodeGen/MachineInstr.cpp b/lib/CodeGen/MachineInstr.cpp index 27e3f66325..966d172bc6 100644 --- a/lib/CodeGen/MachineInstr.cpp +++ b/lib/CodeGen/MachineInstr.cpp @@ -711,6 +711,31 @@ bool MachineInstr::isSafeToMove(const TargetInstrInfo *TII, bool &SawStore) { return true; } +/// isSafeToReMat - Return true if it's safe to rematerialize the specified +/// instruction which defined the specified register instead of copying it. +bool MachineInstr::isSafeToReMat(const TargetInstrInfo *TII, unsigned DstReg) { + if (!TID->isAsCheapAsAMove()) + return false; + bool SawStore = false; + if (!isSafeToMove(TII, SawStore)) + return false; + for (unsigned i = 0, e = getNumOperands(); i != e; ++i) { + MachineOperand &MO = getOperand(i); + if (!MO.isRegister()) + continue; + // FIXME: For now, do not remat any instruction with register operands. + // Later on, we can loosen the restriction is the register operands have + // not been modified between the def and use. Note, this is different from + // MachineSink because the code in no longer in two-address form (at least + // partially). + if (MO.isUse()) + return false; + else if (!MO.isDead() && MO.getReg() != DstReg) + return false; + } + return true; +} + void MachineInstr::dump() const { cerr << " " << *this; } -- cgit v1.2.3