diff options
| -rw-r--r-- | lib/Transforms/Scalar/InstructionCombining.cpp | 8 |
1 files changed, 6 insertions, 2 deletions
diff --git a/lib/Transforms/Scalar/InstructionCombining.cpp b/lib/Transforms/Scalar/InstructionCombining.cpp index 55ef0a8..07eb252 100644 --- a/lib/Transforms/Scalar/InstructionCombining.cpp +++ b/lib/Transforms/Scalar/InstructionCombining.cpp @@ -8936,8 +8936,12 @@ static Instruction *InstCombineLoadCast(InstCombiner &IC, LoadInst &LI) { /// 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 or global variable, it is always safe to load from. - if (isa<AllocaInst>(V) || isa<GlobalVariable>(V)) return true; + // If it is an alloca it is always safe to load from. + if (isa<AllocaInst>(V)) return true; + + // Don't try to evaluate aliases. External weak GV can be null. + if (const GlobalValue *GV = dyn_cast<GlobalVariable>(V)) + 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 |