diff options
Diffstat (limited to 'llvm/lib/Transforms/Scalar/InstructionCombining.cpp')
| -rw-r--r-- | llvm/lib/Transforms/Scalar/InstructionCombining.cpp | 39 |
1 files changed, 0 insertions, 39 deletions
diff --git a/llvm/lib/Transforms/Scalar/InstructionCombining.cpp b/llvm/lib/Transforms/Scalar/InstructionCombining.cpp index 8115a0f0ffa..d77c2b5fc48 100644 --- a/llvm/lib/Transforms/Scalar/InstructionCombining.cpp +++ b/llvm/lib/Transforms/Scalar/InstructionCombining.cpp @@ -11419,45 +11419,6 @@ static Instruction *InstCombineLoadCast(InstCombiner &IC, LoadInst &LI, return 0; } -/// isSafeToLoadUnconditionally - Return true if we know that executing a load -/// from this value cannot trap. If it is not obviously safe to load from the -/// specified pointer, we do a quick local scan of the basic block containing -/// ScanFrom, to determine if the address is already accessed. -static bool isSafeToLoadUnconditionally(Value *V, Instruction *ScanFrom) { - // If it is an alloca it is always safe to load from. - if (isa<AllocaInst>(V)) return true; - - // If it is a global variable it is mostly safe to load from. - if (const GlobalValue *GV = dyn_cast<GlobalVariable>(V)) - // Don't try to evaluate aliases. External weak GV can be null. - return !isa<GlobalAlias>(GV) && !GV->hasExternalWeakLinkage(); - - // Otherwise, be a little bit agressive by scanning the local block where we - // want to check to see if the pointer is already being loaded or stored - // from/to. If so, the previous load or store would have already trapped, - // so there is no harm doing an extra load (also, CSE will later eliminate - // the load entirely). - BasicBlock::iterator BBI = ScanFrom, E = ScanFrom->getParent()->begin(); - - while (BBI != E) { - --BBI; - - // If we see a free or a call (which might do a free) the pointer could be - // marked invalid. - if (isa<FreeInst>(BBI) || - (isa<CallInst>(BBI) && !isa<DbgInfoIntrinsic>(BBI))) - return false; - - if (LoadInst *LI = dyn_cast<LoadInst>(BBI)) { - if (LI->getOperand(0) == V) return true; - } else if (StoreInst *SI = dyn_cast<StoreInst>(BBI)) { - if (SI->getOperand(1) == V) return true; - } - - } - return false; -} - Instruction *InstCombiner::visitLoadInst(LoadInst &LI) { Value *Op = LI.getOperand(0); |

