diff options
Diffstat (limited to 'lib/Transforms')
| -rw-r--r-- | lib/Transforms/Scalar/GVN.cpp | 15 |
1 files changed, 12 insertions, 3 deletions
diff --git a/lib/Transforms/Scalar/GVN.cpp b/lib/Transforms/Scalar/GVN.cpp index fb733ada5a..f282645106 100644 --- a/lib/Transforms/Scalar/GVN.cpp +++ b/lib/Transforms/Scalar/GVN.cpp @@ -59,6 +59,11 @@ static cl::opt<bool> EnablePRE("enable-pre", cl::init(true), cl::Hidden); static cl::opt<bool> EnableLoadPRE("enable-load-pre", cl::init(true)); +// Maximum allowed recursion depth. +static cl::opt<int> +MaxRecurseDepth("max-recurse-depth", cl::Hidden, cl::init(1000), cl::ZeroOrMore, + cl::desc("Max recurse depth (default = 1000)")); + //===----------------------------------------------------------------------===// // ValueTable Class //===----------------------------------------------------------------------===// @@ -647,7 +652,11 @@ void GVN::dump(DenseMap<uint32_t, Value*>& d) { /// 3) we are speculating for this block and have used that to speculate for /// other blocks. static bool IsValueFullyAvailableInBlock(BasicBlock *BB, - DenseMap<BasicBlock*, char> &FullyAvailableBlocks) { + DenseMap<BasicBlock*, char> &FullyAvailableBlocks, + uint32_t RecurseDepth) { + if (RecurseDepth > MaxRecurseDepth) + return false; + // Optimistically assume that the block is fully available and check to see // if we already know about this block in one lookup. std::pair<DenseMap<BasicBlock*, char>::iterator, char> IV = @@ -673,7 +682,7 @@ static bool IsValueFullyAvailableInBlock(BasicBlock *BB, // If the value isn't fully available in one of our predecessors, then it // isn't fully available in this block either. Undo our previous // optimistic assumption and bail out. - if (!IsValueFullyAvailableInBlock(*PI, FullyAvailableBlocks)) + if (!IsValueFullyAvailableInBlock(*PI, FullyAvailableBlocks,RecurseDepth+1)) goto SpeculationFailure; return true; @@ -1570,7 +1579,7 @@ bool GVN::processNonLocalLoad(LoadInst *LI) { for (pred_iterator PI = pred_begin(LoadBB), E = pred_end(LoadBB); PI != E; ++PI) { BasicBlock *Pred = *PI; - if (IsValueFullyAvailableInBlock(Pred, FullyAvailableBlocks)) { + if (IsValueFullyAvailableInBlock(Pred, FullyAvailableBlocks, 0)) { continue; } PredLoads[Pred] = 0; |