diff options
Diffstat (limited to 'lib/Analysis/MemoryDependenceAnalysis.cpp')
-rw-r--r-- | lib/Analysis/MemoryDependenceAnalysis.cpp | 18 |
1 files changed, 14 insertions, 4 deletions
diff --git a/lib/Analysis/MemoryDependenceAnalysis.cpp b/lib/Analysis/MemoryDependenceAnalysis.cpp index 38bf5dd..1faa046 100644 --- a/lib/Analysis/MemoryDependenceAnalysis.cpp +++ b/lib/Analysis/MemoryDependenceAnalysis.cpp @@ -351,15 +351,23 @@ getLoadLoadClobberFullWidthSize(const Value *MemLocBase, int64_t MemLocOffs, /// getPointerDependencyFrom - Return the instruction on which a memory /// location depends. If isLoad is true, this routine ignores may-aliases with /// read-only operations. If isLoad is false, this routine ignores may-aliases -/// with reads from read-only locations. +/// with reads from read-only locations. If possible, pass the query +/// instruction as well; this function may take advantage of the metadata +/// annotated to the query instruction to refine the result. MemDepResult MemoryDependenceAnalysis:: getPointerDependencyFrom(const AliasAnalysis::Location &MemLoc, bool isLoad, - BasicBlock::iterator ScanIt, BasicBlock *BB) { + BasicBlock::iterator ScanIt, BasicBlock *BB, + Instruction *QueryInst) { const Value *MemLocBase = 0; int64_t MemLocOffset = 0; - unsigned Limit = BlockScanLimit; + bool isInvariantLoad = false; + if (isLoad && QueryInst) { + LoadInst *LI = dyn_cast<LoadInst>(QueryInst); + if (LI && LI->getMetadata(LLVMContext::MD_invariant_load) != 0) + isInvariantLoad = true; + } // Walk backwards through the basic block, looking for dependencies. while (ScanIt != BB->begin()) { @@ -474,6 +482,8 @@ getPointerDependencyFrom(const AliasAnalysis::Location &MemLoc, bool isLoad, continue; if (R == AliasAnalysis::MustAlias) return MemDepResult::getDef(Inst); + if (isInvariantLoad) + continue; return MemDepResult::getClobber(Inst); } @@ -571,7 +581,7 @@ MemDepResult MemoryDependenceAnalysis::getDependency(Instruction *QueryInst) { isLoad |= II->getIntrinsicID() == Intrinsic::lifetime_start; LocalCache = getPointerDependencyFrom(MemLoc, isLoad, ScanPos, - QueryParent); + QueryParent, QueryInst); } else if (isa<CallInst>(QueryInst) || isa<InvokeInst>(QueryInst)) { CallSite QueryCS(QueryInst); bool isReadOnly = AA->onlyReadsMemory(QueryCS); |