diff options
Diffstat (limited to 'llvm/lib/CodeGen/TailDuplicator.cpp')
| -rw-r--r-- | llvm/lib/CodeGen/TailDuplicator.cpp | 29 |
1 files changed, 0 insertions, 29 deletions
diff --git a/llvm/lib/CodeGen/TailDuplicator.cpp b/llvm/lib/CodeGen/TailDuplicator.cpp index 943bd18c6c8b..54fc6ee45d00 100644 --- a/llvm/lib/CodeGen/TailDuplicator.cpp +++ b/llvm/lib/CodeGen/TailDuplicator.cpp @@ -70,12 +70,6 @@ static cl::opt<unsigned> TailDupIndirectBranchSize( "end with indirect branches."), cl::init(20), cl::Hidden); -static cl::opt<unsigned> TailDupJmpTableLoopSize( - "tail-dup-jmptable-loop-size", - cl::desc("Maximum loop latches to consider tail duplication that are " - "successors of loop header."), - cl::init(128), cl::Hidden); - static cl::opt<bool> TailDupVerify("tail-dup-verify", cl::desc("Verify sanity of PHI instructions during taildup"), @@ -569,29 +563,6 @@ bool TailDuplicator::shouldTailDuplicate(bool IsSimple, if (TailBB.isSuccessor(&TailBB)) return false; - // When doing tail-duplication with jumptable loops like: - // 1 -> 2 <-> 3 | - // \ <-> 4 | - // \ <-> 5 | - // \ <-> ... | - // \---> rest | - // quadratic number of edges and much more loops are added to CFG. This - // may cause compile time regression when jumptable is quiet large. - // So set the limit on jumptable cases. - auto isLargeJumpTableLoop = [](const MachineBasicBlock &TailBB) { - const SmallPtrSet<const MachineBasicBlock *, 8> Preds(TailBB.pred_begin(), - TailBB.pred_end()); - // Check the basic block has large number of successors, all of them only - // have one successor which is the basic block itself. - return llvm::count_if( - TailBB.successors(), [&](const MachineBasicBlock *SuccBB) { - return Preds.count(SuccBB) && SuccBB->succ_size() == 1; - }) > TailDupJmpTableLoopSize; - }; - - if (isLargeJumpTableLoop(TailBB)) - return false; - // Set the limit on the cost to duplicate. When optimizing for size, // duplicate only one, because one branch instruction can be eliminated to // compensate for the duplication. |