diff options
Diffstat (limited to 'llvm/lib/Analysis')
| -rw-r--r-- | llvm/lib/Analysis/Lint.cpp | 5 | ||||
| -rw-r--r-- | llvm/lib/Analysis/Loads.cpp | 12 |
2 files changed, 15 insertions, 2 deletions
diff --git a/llvm/lib/Analysis/Lint.cpp b/llvm/lib/Analysis/Lint.cpp index 0f5599e8204..15acc783f07 100644 --- a/llvm/lib/Analysis/Lint.cpp +++ b/llvm/lib/Analysis/Lint.cpp @@ -829,8 +829,9 @@ Value *Lint::findValueImpl(Value *V, bool OffsetOk, for (;;) { if (!VisitedBlocks.insert(BB).second) break; - if (Value *U = FindAvailableLoadedValue(L->getPointerOperand(), - BB, BBI, 6, AA)) + if (Value *U = + FindAvailableLoadedValue(L->getPointerOperand(), + BB, BBI, DefMaxInstsToScan, AA)) return findValueImpl(U, OffsetOk, Visited); if (BBI != BB->begin()) break; BB = BB->getUniquePredecessor(); diff --git a/llvm/lib/Analysis/Loads.cpp b/llvm/lib/Analysis/Loads.cpp index 4d6d960f159..a544ac0c504 100644 --- a/llvm/lib/Analysis/Loads.cpp +++ b/llvm/lib/Analysis/Loads.cpp @@ -161,6 +161,18 @@ bool llvm::isSafeToLoadUnconditionally(Value *V, Instruction *ScanFrom, return false; } +/// DefMaxInstsToScan - the default number of maximum instructions +/// to scan in the block, used by FindAvailableLoadedValue(). +/// FindAvailableLoadedValue() was introduced in r60148, to improve jump +/// threading in part by eliminating partially redundant loads. +/// At that point, the value of MaxInstsToScan was already set to '6' +/// without documented explanation. +cl::opt<unsigned> +llvm::DefMaxInstsToScan("available-load-scan-limit", cl::init(6), cl::Hidden, + cl::desc("Use this to specify the default maximum number of instructions " + "to scan backward from a given instruction, when searching for " + "available loaded value")); + /// \brief Scan the ScanBB block backwards to see if we have the value at the /// memory address *Ptr locally available within a small number of instructions. /// |
