diff options
Diffstat (limited to 'llvm/lib/CodeGen/BranchFolding.cpp')
| -rw-r--r-- | llvm/lib/CodeGen/BranchFolding.cpp | 35 |
1 files changed, 1 insertions, 34 deletions
diff --git a/llvm/lib/CodeGen/BranchFolding.cpp b/llvm/lib/CodeGen/BranchFolding.cpp index 665424805db..fb8d98f228e 100644 --- a/llvm/lib/CodeGen/BranchFolding.cpp +++ b/llvm/lib/CodeGen/BranchFolding.cpp @@ -125,8 +125,6 @@ BranchFolder::BranchFolder(bool defaultEnableTailMerge, bool CommonHoist, } } -/// RemoveDeadBlock - Remove the specified dead machine basic block from the -/// function, updating the CFG. void BranchFolder::RemoveDeadBlock(MachineBasicBlock *MBB) { assert(MBB->pred_empty() && "MBB must be dead!"); DEBUG(dbgs() << "\nRemoving MBB: " << *MBB); @@ -146,9 +144,6 @@ void BranchFolder::RemoveDeadBlock(MachineBasicBlock *MBB) { MLI->removeBlock(MBB); } -/// OptimizeFunction - Perhaps branch folding, tail merging and other -/// CFG optimizations on the given function. Block placement changes the layout -/// and may create new tail merging opportunities. bool BranchFolder::OptimizeFunction(MachineFunction &MF, const TargetInstrInfo *tii, const TargetRegisterInfo *tri, @@ -350,8 +345,6 @@ static unsigned ComputeCommonTailLength(MachineBasicBlock *MBB1, return TailLen; } -/// ReplaceTailWithBranchTo - Delete the instruction OldInst and everything -/// after it, replacing it with an unconditional branch to NewDest. void BranchFolder::ReplaceTailWithBranchTo(MachineBasicBlock::iterator OldInst, MachineBasicBlock *NewDest) { TII->ReplaceTailWithBranchTo(OldInst, NewDest); @@ -364,9 +357,6 @@ void BranchFolder::ReplaceTailWithBranchTo(MachineBasicBlock::iterator OldInst, ++NumTailMerge; } -/// SplitMBBAt - Given a machine basic block and an iterator into it, split the -/// MBB so that the part before the iterator falls into the part starting at the -/// iterator. This returns the new MBB. MachineBasicBlock *BranchFolder::SplitMBBAt(MachineBasicBlock &CurMBB, MachineBasicBlock::iterator BBI1, const BasicBlock *BB) { @@ -635,16 +625,6 @@ ProfitableToMerge(MachineBasicBlock *MBB1, MachineBasicBlock *MBB2, (I1 == MBB1->begin() || I2 == MBB2->begin()); } -/// ComputeSameTails - Look through all the blocks in MergePotentials that have -/// hash CurHash (guaranteed to match the last element). Build the vector -/// SameTails of all those that have the (same) largest number of instructions -/// in common of any pair of these blocks. SameTails entries contain an -/// iterator into MergePotentials (from which the MachineBasicBlock can be -/// found) and a MachineBasicBlock::iterator into that MBB indicating the -/// instruction where the matching code sequence begins. -/// Order of elements in SameTails is the reverse of the order in which -/// those blocks appear in MergePotentials (where they are not necessarily -/// consecutive). unsigned BranchFolder::ComputeSameTails(unsigned CurHash, unsigned MinCommonTailLength, MachineBasicBlock *SuccBB, @@ -681,8 +661,6 @@ unsigned BranchFolder::ComputeSameTails(unsigned CurHash, return maxCommonTailLength; } -/// RemoveBlocksWithHash - Remove all blocks with hash CurHash from -/// MergePotentials, restoring branches at ends of blocks as appropriate. void BranchFolder::RemoveBlocksWithHash(unsigned CurHash, MachineBasicBlock *SuccBB, MachineBasicBlock *PredBB) { @@ -702,8 +680,6 @@ void BranchFolder::RemoveBlocksWithHash(unsigned CurHash, MergePotentials.erase(CurMPIter, MergePotentials.end()); } -/// CreateCommonTailOnlyBlock - None of the blocks to be tail-merged consist -/// only of the common tail. Create a block that does by splitting one. bool BranchFolder::CreateCommonTailOnlyBlock(MachineBasicBlock *&PredBB, MachineBasicBlock *SuccBB, unsigned maxCommonTailLength, @@ -754,8 +730,6 @@ bool BranchFolder::CreateCommonTailOnlyBlock(MachineBasicBlock *&PredBB, return true; } -/// MergeCommonTailDebugLocs - Create merged DebugLocs of identical instructions -/// across SameTails and assign it to the instruction in common tail. void BranchFolder::MergeCommonTailDebugLocs(unsigned commonTailIndex) { MachineBasicBlock *MBB = SameTails[commonTailIndex].getBlock(); @@ -945,7 +919,7 @@ bool BranchFolder::TryTailMergeBlocks(MachineBasicBlock *SuccBB, // Recompute common tail MBB's edge weights and block frequency. setCommonTailEdgeWeights(*MBB); - // Merge debug locations across identical instructions for common tail + // Merge debug locations across identical instructions for common tail. MergeCommonTailDebugLocs(commonTailIndex); // MBB is common tail. Adjust all other BB's to jump to this one. @@ -1261,8 +1235,6 @@ static DebugLoc getBranchDebugLoc(MachineBasicBlock &MBB) { return DebugLoc(); } -/// OptimizeBlock - Analyze and optimize control flow related to the specified -/// block. This is never called on the entry block. bool BranchFolder::OptimizeBlock(MachineBasicBlock *MBB) { bool MadeChange = false; MachineFunction &MF = *MBB->getParent(); @@ -1703,8 +1675,6 @@ ReoptimizeBlock: // Hoist Common Code //===----------------------------------------------------------------------===// -/// HoistCommonCode - Hoist common instruction sequences at the start of basic -/// blocks to their common predecessor. bool BranchFolder::HoistCommonCode(MachineFunction &MF) { bool MadeChange = false; for (MachineFunction::iterator I = MF.begin(), E = MF.end(); I != E; ) { @@ -1838,9 +1808,6 @@ MachineBasicBlock::iterator findHoistingInsertPosAndDeps(MachineBasicBlock *MBB, return PI; } -/// HoistCommonCodeInSuccs - If the successors of MBB has common instruction -/// sequence at the start of the function, move the instructions before MBB -/// terminator if it's legal. bool BranchFolder::HoistCommonCodeInSuccs(MachineBasicBlock *MBB) { MachineBasicBlock *TBB = nullptr, *FBB = nullptr; SmallVector<MachineOperand, 4> Cond; |
