diff options
Diffstat (limited to 'lib/CodeGen')
| -rw-r--r-- | lib/CodeGen/LiveIntervalAnalysis.cpp | 54 |
1 files changed, 32 insertions, 22 deletions
diff --git a/lib/CodeGen/LiveIntervalAnalysis.cpp b/lib/CodeGen/LiveIntervalAnalysis.cpp index f902f4be96..2b22faf1cc 100644 --- a/lib/CodeGen/LiveIntervalAnalysis.cpp +++ b/lib/CodeGen/LiveIntervalAnalysis.cpp @@ -644,20 +644,27 @@ bool LiveIntervals::isReMaterializable(const LiveInterval &li, bool LiveIntervals::tryFoldMemoryOperand(MachineInstr* &MI, VirtRegMap &vrm, MachineInstr *DefMI, unsigned InstrIdx, unsigned OpIdx, - unsigned NumUses, + SmallVector<unsigned, 2> &UseOps, bool isSS, int Slot, unsigned Reg) { // FIXME: fold subreg use if (MI->getOperand(OpIdx).getSubReg()) return false; - // FIXME: It may be possible to fold load when there are multiple uses. - // e.g. On x86, TEST32rr r, r -> CMP32rm [mem], 0 - if (NumUses > 1) - return false; + MachineInstr *fmi = NULL; + + if (UseOps.size() < 2) + fmi = isSS ? mri_->foldMemoryOperand(MI, OpIdx, Slot) + : mri_->foldMemoryOperand(MI, OpIdx, DefMI); + else { + if (OpIdx != UseOps[0]) + // Must be two-address instruction + one more use. Not going to fold. + return false; + // It may be possible to fold load when there are multiple uses. + // e.g. On x86, TEST32rr r, r -> CMP32rm [mem], 0 + fmi = isSS ? mri_->foldMemoryOperand(MI, UseOps, Slot) + : mri_->foldMemoryOperand(MI, UseOps, DefMI); + } - MachineInstr *fmi = isSS - ? mri_->foldMemoryOperand(MI, OpIdx, Slot) - : mri_->foldMemoryOperand(MI, OpIdx, DefMI); if (fmi) { // Attempt to fold the memory reference into the instruction. If // we can do this, we don't need to insert spill code. @@ -768,7 +775,9 @@ rewriteInstructionForSpills(const LiveInterval &li, bool TrySplit, HasUse = mop.isUse(); HasDef = mop.isDef(); - unsigned NumUses = HasUse; + SmallVector<unsigned, 2> UseOps; + if (HasUse) + UseOps.push_back(i); std::vector<unsigned> UpdateOps; for (unsigned j = i+1, e = MI->getNumOperands(); j != e; ++j) { if (!MI->getOperand(j).isRegister()) @@ -779,7 +788,7 @@ rewriteInstructionForSpills(const LiveInterval &li, bool TrySplit, if (RegJ == RegI) { UpdateOps.push_back(j); if (MI->getOperand(j).isUse()) - ++NumUses; + UseOps.push_back(j); HasUse |= MI->getOperand(j).isUse(); HasDef |= MI->getOperand(j).isDef(); } @@ -787,7 +796,7 @@ rewriteInstructionForSpills(const LiveInterval &li, bool TrySplit, if (TryFold && tryFoldMemoryOperand(MI, vrm, ReMatDefMI, index, i, - NumUses, FoldSS, FoldSlot, Reg)) { + UseOps, FoldSS, FoldSlot, Reg)) { // Folding the load/store can completely change the instruction in // unpredictable ways, rescan it from the beginning. HasUse = false; @@ -1207,6 +1216,7 @@ addIntervalsForSpills(const LiveInterval &li, if (!TrySplit) return NewLIs; + SmallVector<unsigned, 2> UseOps; if (NeedStackSlot) { int Id = SpillMBBs.find_first(); while (Id != -1) { @@ -1217,7 +1227,7 @@ addIntervalsForSpills(const LiveInterval &li, bool isReMat = vrm.isReMaterialized(VReg); MachineInstr *MI = getInstructionFromIndex(index); int OpIdx = -1; - unsigned NumUses = 0; + UseOps.clear(); if (spills[i].canFold) { for (unsigned j = 0, ee = MI->getNumOperands(); j != ee; ++j) { MachineOperand &MO = MI->getOperand(j); @@ -1230,20 +1240,20 @@ addIntervalsForSpills(const LiveInterval &li, // Can't fold if it's two-address code and the use isn't the // first and only use. if (isReMat || - (NumUses == 0 && !alsoFoldARestore(Id, index, VReg, RestoreMBBs, - RestoreIdxes))) { + (UseOps.empty() && !alsoFoldARestore(Id, index, VReg, + RestoreMBBs, RestoreIdxes))) { OpIdx = -1; break; } - ++NumUses; + UseOps.push_back(j); } } // Fold the store into the def if possible. bool Folded = false; if (OpIdx != -1) { - if (tryFoldMemoryOperand(MI, vrm, NULL, index, OpIdx, NumUses, + if (tryFoldMemoryOperand(MI, vrm, NULL, index, OpIdx, UseOps, true, Slot, VReg)) { - if (NumUses) + if (!UseOps.empty()) // Folded a two-address instruction, do not issue a load. eraseRestoreInfo(Id, index, VReg, RestoreMBBs, RestoreIdxes); Folded = true; @@ -1267,8 +1277,8 @@ addIntervalsForSpills(const LiveInterval &li, continue; unsigned VReg = restores[i].vreg; MachineInstr *MI = getInstructionFromIndex(index); - unsigned NumUses = 0; int OpIdx = -1; + UseOps.clear(); if (restores[i].canFold) { for (unsigned j = 0, ee = MI->getNumOperands(); j != ee; ++j) { MachineOperand &MO = MI->getOperand(j); @@ -1280,10 +1290,10 @@ addIntervalsForSpills(const LiveInterval &li, OpIdx = -1; break; } - if (NumUses == 0) + if (UseOps.empty()) // Use the first use index. OpIdx = (int)j; - ++NumUses; + UseOps.push_back(j); } } @@ -1298,9 +1308,9 @@ addIntervalsForSpills(const LiveInterval &li, if (isLoadSS || (ReMatDefMI->getInstrDescriptor()->Flags & M_LOAD_FLAG)) Folded = tryFoldMemoryOperand(MI, vrm, ReMatDefMI, index, OpIdx, - NumUses, isLoadSS, LdSlot, VReg); + UseOps, isLoadSS, LdSlot, VReg); } else - Folded = tryFoldMemoryOperand(MI, vrm, NULL, index, OpIdx, NumUses, + Folded = tryFoldMemoryOperand(MI, vrm, NULL, index, OpIdx, UseOps, true, Slot, VReg); } // If folding is not possible / failed, then tell the spiller to issue a |