> BranchFolding.cpp updated: 1.65 -> 1.66 > --- > Log message: > > Throttle tail merging; handling blocks with large numbers of > predecessors > is too slow.
Thanks Dale, Please make this a hidden command line option like loop-unswitch- threshold. -Chris > > --- > Diffs of the changes: (+6 -2) > > BranchFolding.cpp | 8 ++++++-- > 1 files changed, 6 insertions(+), 2 deletions(-) > > > Index: llvm/lib/CodeGen/BranchFolding.cpp > diff -u llvm/lib/CodeGen/BranchFolding.cpp:1.65 llvm/lib/CodeGen/ > BranchFolding.cpp:1.66 > --- llvm/lib/CodeGen/BranchFolding.cpp:1.65 Mon Jun 4 18:52:54 2007 > +++ llvm/lib/CodeGen/BranchFolding.cpp Thu Jun 7 19:34:27 2007 > @@ -564,6 +564,9 @@ > return MadeChange; > } > > +// Throttle for huge numbers of predecessors (compile speed problems) > +#define THRESHOLD 100 > + > bool BranchFolder::TailMergeBlocks(MachineFunction &MF) { > > if (!EnableTailMerge) return false; > @@ -577,7 +580,8 @@ > MergePotentials.push_back(std::make_pair(HashEndOfMBB(I, > 2U), I)); > } > // See if we can do any tail merging on those. > - MadeChange |= TryMergeBlocks(NULL, NULL); > + if (MergePotentials.size() < THRESHOLD) > + MadeChange |= TryMergeBlocks(NULL, NULL); > > // Look at blocks (IBB) with multiple predecessors (PBB). > // We change each predecessor to a canonical form, by > @@ -599,7 +603,7 @@ > // transformations.) > > for (MachineFunction::iterator I = MF.begin(), E = MF.end(); I ! > = E; ++I) { > - if (!I->succ_empty() && I->pred_size() >= 2) { > + if (!I->succ_empty() && I->pred_size() >= 2 && I->pred_size() > < THRESHOLD) { > MachineBasicBlock *IBB = I; > MachineBasicBlock *PredBB = prior(I); > MergePotentials.clear(); > > > > _______________________________________________ > llvm-commits mailing list > llvm-commits@cs.uiuc.edu > http://lists.cs.uiuc.edu/mailman/listinfo/llvm-commits _______________________________________________ llvm-commits mailing list llvm-commits@cs.uiuc.edu http://lists.cs.uiuc.edu/mailman/listinfo/llvm-commits