Index: include/llvm/Analysis/Loads.h
===================================================================
--- include/llvm/Analysis/Loads.h
+++ include/llvm/Analysis/Loads.h
@@ -24,11 +24,17 @@
 class MDNode;
 
 /// 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.
+/// from this value cannot trap.
+///
+/// If the ScanFrom is specified this method performs context-sensitive analysis
+/// and returns true if it is safe to load immediately before the ScanFrom.
+///
+/// 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.
 bool isSafeToLoadUnconditionally(Value *V, unsigned Align,
                                  Instruction *ScanFrom,
+                                 const DataLayout &DL,
                                  const DominatorTree *DT = nullptr,
                                  const TargetLibraryInfo *TLI = nullptr);
 
Index: lib/Analysis/Loads.cpp
===================================================================
--- lib/Analysis/Loads.cpp
+++ lib/Analysis/Loads.cpp
@@ -64,18 +64,22 @@
 /// load from the pointer.
 bool llvm::isSafeToLoadUnconditionally(Value *V, unsigned Align,
                                        Instruction *ScanFrom,
+                                       const DataLayout &DL,
                                        const DominatorTree *DT,
                                        const TargetLibraryInfo *TLI) {
-  const DataLayout &DL = ScanFrom->getModule()->getDataLayout();
-
   // Zero alignment means that the load has the ABI alignment for the target
   if (Align == 0)
     Align = DL.getABITypeAlignment(V->getType()->getPointerElementType());
   assert(isPowerOf2_32(Align));
 
-  if (isDereferenceableAndAlignedPointer(V, Align, DL, ScanFrom, DT, TLI))
+  // If DT is not specified we can't make context-sensitive query
+  const Instruction* CtxI = DT ? ScanFrom : nullptr;
+  if (isDereferenceableAndAlignedPointer(V, Align, DL, CtxI, DT, TLI))
     return true;
 
+  if (!ScanFrom)
+    return false;
+
   PointerType *AddrTy = cast<PointerType>(V->getType());
   uint64_t LoadSize = DL.getTypeStoreSize(AddrTy->getElementType());
 
Index: lib/Transforms/InstCombine/InstCombineLoadStoreAlloca.cpp
===================================================================
--- lib/Transforms/InstCombine/InstCombineLoadStoreAlloca.cpp
+++ lib/Transforms/InstCombine/InstCombineLoadStoreAlloca.cpp
@@ -852,8 +852,8 @@
     if (SelectInst *SI = dyn_cast<SelectInst>(Op)) {
       // load (select (Cond, &V1, &V2))  --> select(Cond, load &V1, load &V2).
       unsigned Align = LI.getAlignment();
-      if (isSafeToLoadUnconditionally(SI->getOperand(1), Align, SI) &&
-          isSafeToLoadUnconditionally(SI->getOperand(2), Align, SI)) {
+      if (isSafeToLoadUnconditionally(SI->getOperand(1), Align, SI, DL) &&
+          isSafeToLoadUnconditionally(SI->getOperand(2), Align, SI, DL)) {
         LoadInst *V1 = Builder->CreateLoad(SI->getOperand(1),
                                            SI->getOperand(1)->getName()+".val");
         LoadInst *V2 = Builder->CreateLoad(SI->getOperand(2),
Index: lib/Transforms/Scalar/SROA.cpp
===================================================================
--- lib/Transforms/Scalar/SROA.cpp
+++ lib/Transforms/Scalar/SROA.cpp
@@ -1192,7 +1192,7 @@
     // If this pointer is always safe to load, or if we can prove that there
     // is already a load in the block, then we can move the load to the pred
     // block.
-    if (isSafeToLoadUnconditionally(InVal, MaxAlign, TI))
+    if (isSafeToLoadUnconditionally(InVal, MaxAlign, TI, DL))
       continue;
 
     return false;
@@ -1270,9 +1270,9 @@
     // Both operands to the select need to be dereferencable, either
     // absolutely (e.g. allocas) or at this point because we can see other
     // accesses to it.
-    if (!isSafeToLoadUnconditionally(TValue, LI->getAlignment(), LI))
+    if (!isSafeToLoadUnconditionally(TValue, LI->getAlignment(), LI, DL))
       return false;
-    if (!isSafeToLoadUnconditionally(FValue, LI->getAlignment(), LI))
+    if (!isSafeToLoadUnconditionally(FValue, LI->getAlignment(), LI, DL))
       return false;
   }
 
Index: lib/Transforms/Scalar/ScalarReplAggregates.cpp
===================================================================
--- lib/Transforms/Scalar/ScalarReplAggregates.cpp
+++ lib/Transforms/Scalar/ScalarReplAggregates.cpp
@@ -1149,10 +1149,10 @@
     // Both operands to the select need to be dereferencable, either absolutely
     // (e.g. allocas) or at this point because we can see other accesses to it.
     if (!isSafeToLoadUnconditionally(SI->getTrueValue(), LI->getAlignment(),
-                                     LI))
+                                     LI, DL))
       return false;
     if (!isSafeToLoadUnconditionally(SI->getFalseValue(), LI->getAlignment(),
-                                     LI))
+                                     LI, DL))
       return false;
   }
 
@@ -1225,7 +1225,7 @@
 
     // If this pointer is always safe to load, or if we can prove that there is
     // already a load in the block, then we can move the load to the pred block.
-    if (isSafeToLoadUnconditionally(InVal, MaxAlign, Pred->getTerminator()))
+    if (isSafeToLoadUnconditionally(InVal, MaxAlign, Pred->getTerminator(), DL))
       continue;
 
     return false;
Index: lib/Transforms/Scalar/TailRecursionElimination.cpp
===================================================================
--- lib/Transforms/Scalar/TailRecursionElimination.cpp
+++ lib/Transforms/Scalar/TailRecursionElimination.cpp
@@ -454,9 +454,10 @@
       // does not write to memory and the load provably won't trap.
       // FIXME: Writes to memory only matter if they may alias the pointer
       // being loaded from.
+      const DataLayout &DL = L->getModule()->getDataLayout();
       if (CI->mayWriteToMemory() ||
           !isSafeToLoadUnconditionally(L->getPointerOperand(),
-                                       L->getAlignment(), L))
+                                       L->getAlignment(), L, DL))
         return false;
     }
   }