summaryrefslogtreecommitdiffstats
path: root/llvm/lib/Transforms/Scalar/InstructionCombining.cpp
diff options
context:
space:
mode:
Diffstat (limited to 'llvm/lib/Transforms/Scalar/InstructionCombining.cpp')
-rw-r--r--llvm/lib/Transforms/Scalar/InstructionCombining.cpp39
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);
OpenPOWER on IntegriCloud