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| author | Vedant Kumar <vsk@apple.com> | 2018-11-19 19:54:27 +0000 |
|---|---|---|
| committer | Vedant Kumar <vsk@apple.com> | 2018-11-19 19:54:27 +0000 |
| commit | 4de31bba51b884bdfc7eb688958d9dc517da8353 (patch) | |
| tree | 8bfd8a142284649e9502ed52fe786cd312fc5922 /llvm/lib/Transforms/Utils/SimplifyCFG.cpp | |
| parent | 740122fb8cb6a38ad072d3da26f6641434f30761 (diff) | |
| download | bcm5719-llvm-4de31bba51b884bdfc7eb688958d9dc517da8353.tar.gz bcm5719-llvm-4de31bba51b884bdfc7eb688958d9dc517da8353.zip | |
[IR] Add hasNPredecessors, hasNPredecessorsOrMore to BasicBlock
Add methods to BasicBlock which make it easier to efficiently check
whether a block has N (or more) predecessors.
This can be more efficient than using pred_size(), which is a linear
time operation.
We might consider adding similar methods for successors. I haven't done
so in this patch because succ_size() is already O(1).
With this patch applied, I measured a 0.065% compile-time reduction in
user time for running `opt -O3` on the sqlite3 amalgamation (30 trials).
The change in mergeStoreIntoSuccessor alone saves 45 million linked list
iterations in a stage2 Release build of llc.
See llvm.org/PR39702 for a harder but more general way of achieving
similar results.
Differential Revision: https://reviews.llvm.org/D54686
llvm-svn: 347256
Diffstat (limited to 'llvm/lib/Transforms/Utils/SimplifyCFG.cpp')
| -rw-r--r-- | llvm/lib/Transforms/Utils/SimplifyCFG.cpp | 6 |
1 files changed, 3 insertions, 3 deletions
diff --git a/llvm/lib/Transforms/Utils/SimplifyCFG.cpp b/llvm/lib/Transforms/Utils/SimplifyCFG.cpp index af9d2eaf253..cbf9fc16c3d 100644 --- a/llvm/lib/Transforms/Utils/SimplifyCFG.cpp +++ b/llvm/lib/Transforms/Utils/SimplifyCFG.cpp @@ -693,7 +693,7 @@ Value *SimplifyCFGOpt::isValueEqualityComparison(Instruction *TI) { if (SwitchInst *SI = dyn_cast<SwitchInst>(TI)) { // Do not permit merging of large switch instructions into their // predecessors unless there is only one predecessor. - if (SI->getNumSuccessors() * pred_size(SI->getParent()) <= 128) + if (!SI->getParent()->hasNPredecessorsOrMore(128 / SI->getNumSuccessors())) CV = SI->getCondition(); } else if (BranchInst *BI = dyn_cast<BranchInst>(TI)) if (BI->isConditional() && BI->getCondition()->hasOneUse()) @@ -2890,7 +2890,7 @@ static Value *ensureValueAvailableInSuccessor(Value *V, BasicBlock *BB, if (!AlternativeV) break; - assert(pred_size(Succ) == 2); + assert(Succ->hasNPredecessors(2)); auto PredI = pred_begin(Succ); BasicBlock *OtherPredBB = *PredI == BB ? *++PredI : *PredI; if (PHI->getIncomingValueForBlock(OtherPredBB) == AlternativeV) @@ -5774,7 +5774,7 @@ bool SimplifyCFGOpt::SimplifyUncondBranch(BranchInst *BI, // backedge, so we can eliminate BB. bool NeedCanonicalLoop = Options.NeedCanonicalLoop && - (LoopHeaders && pred_size(BB) > 1 && + (LoopHeaders && BB->hasNPredecessorsOrMore(2) && (LoopHeaders->count(BB) || LoopHeaders->count(Succ))); BasicBlock::iterator I = BB->getFirstNonPHIOrDbg()->getIterator(); if (I->isTerminator() && BB != &BB->getParent()->getEntryBlock() && |
