Index: lib/Transforms/Scalar/JumpThreading.cpp
===================================================================
--- lib/Transforms/Scalar/JumpThreading.cpp
+++ lib/Transforms/Scalar/JumpThreading.cpp
@@ -935,12 +935,18 @@
     return false;
 
   Value *LoadedPtr = LI->getOperand(0);
-
-  // If the loaded operand is defined in the LoadBB, it can't be available.
-  // TODO: Could do simple PHI translation, that would be fun :)
-  if (Instruction *PtrOp = dyn_cast<Instruction>(LoadedPtr))
-    if (PtrOp->getParent() == LoadBB)
+  PHINode *TranslatableLoadedPhiPtr = dyn_cast<PHINode>(LoadedPtr);
+
+  if (Instruction *PtrOp = dyn_cast<Instruction>(LoadedPtr)) {
+    // If the loaded operand is a phi not inside LoadBB, we can not
+    // phi translate it.
+    if (TranslatableLoadedPhiPtr && PtrOp->getParent() != LoadBB)
+      TranslatableLoadedPhiPtr = nullptr;
+    // If the loaded operand is defined in the LoadBB and its not a phi,
+    // it can't be available.
+    if (!TranslatableLoadedPhiPtr && PtrOp->getParent() == LoadBB)
       return false;
+  }
 
   // Scan a few instructions up from the load, to see if it is obviously live at
   // the entry to its block.
@@ -991,24 +997,35 @@
     if (!PredsScanned.insert(PredBB).second)
       continue;
 
-    // Scan the predecessor to see if the value is available in the pred.
     BBIt = PredBB->end();
     unsigned NumScanedInst = 0;
-    Value *PredAvailable =
-        FindAvailableLoadedValue(LI, PredBB, BBIt, DefMaxInstsToScan, nullptr,
-                                 &IsLoadCSE, &NumScanedInst);
-
-    // If PredBB has a single predecessor, continue scanning through the single
-    // precessor.
+    Value *PredAvailable = nullptr;
+    // NOTE: We don't CSE load that is volatile or anything stronger than
+    // unordered, that should have been checked when we entered the function.
+    assert(isUnordered() && "Attempting to CSE volatile or atomic loads");
+    // If this is a load on a phi pointer, phi-translate it and search
+    // for available load/store to the pointer in predecessors.
+    Value *Ptr =
+        TranslatableLoadedPhiPtr
+            ? TranslatableLoadedPhiPtr->getIncomingValueForBlock(PredBB)
+            : LI->getPointerOperand();
+
+    PredAvailable = FindAvailablePtrLoadStore(
+        Ptr, LI->getType(), LI->isAtomic(), PredBB, BBIt, DefMaxInstsToScan,
+        nullptr, &IsLoadCSE, &NumScanedInst);
+
+    // If PredBB has a single predecessor, continue scanning through the
+    // single precessor.
     BasicBlock *SinglePredBB = PredBB;
     while (!PredAvailable && SinglePredBB && BBIt == SinglePredBB->begin() &&
            NumScanedInst < DefMaxInstsToScan) {
       SinglePredBB = SinglePredBB->getSinglePredecessor();
       if (SinglePredBB) {
         BBIt = SinglePredBB->end();
-        PredAvailable = FindAvailableLoadedValue(
-            LI, SinglePredBB, BBIt, (DefMaxInstsToScan - NumScanedInst),
-            nullptr, &IsLoadCSE, &NumScanedInst);
+        PredAvailable = FindAvailablePtrLoadStore(
+            Ptr, LI->getType(), LI->isAtomic(), SinglePredBB, BBIt,
+            (DefMaxInstsToScan - NumScanedInst), nullptr, &IsLoadCSE,
+            &NumScanedInst);
       }
     }
 
@@ -1071,9 +1088,13 @@
   if (UnavailablePred) {
     assert(UnavailablePred->getTerminator()->getNumSuccessors() == 1 &&
            "Can't handle critical edge here!");
+    Value *Ptr = TranslatableLoadedPhiPtr
+                     ? TranslatableLoadedPhiPtr->getIncomingValueForBlock(
+                           UnavailablePred)
+                     : LoadedPtr;
     LoadInst *NewVal =
-        new LoadInst(LoadedPtr, LI->getName() + ".pr", false,
-                     LI->getAlignment(), LI->getOrdering(), LI->getSynchScope(),
+        new LoadInst(Ptr, LI->getName() + ".pr", false, LI->getAlignment(),
+                     LI->getOrdering(), LI->getSynchScope(),
                      UnavailablePred->getTerminator());
     NewVal->setDebugLoc(LI->getDebugLoc());
     if (AATags)
Index: test/Transforms/JumpThreading/thread-loads.ll
===================================================================
--- test/Transforms/JumpThreading/thread-loads.ll
+++ test/Transforms/JumpThreading/thread-loads.ll
@@ -381,6 +381,41 @@
 declare void @fn3(i64)
 
 
+; Make sure we phi-translate and make the partially redundant load in
+; merge fully redudant and then we can jump-thread the block with the
+; store.
+;
+; CHECK-LABEL: define i32 @phi_translate_partial_redundant_loads(i32, i32*, i32*
+; CHECK: merge.thread:
+; CHECK: store
+; CHECK: br label %left_x
+;
+; CHECK: left_x:
+; CHECK-NEXT: ret i32 20
+define i32 @phi_translate_partial_redundant_loads(i32, i32*, i32*)  {
+  %cmp0 = icmp ne i32 %0, 0
+  br i1 %cmp0, label %left, label %right
+
+left:
+  store i32 1, i32* %1, align 4
+  br label %merge
+
+right:
+  br label %merge
+
+merge:
+  %phiptr = phi i32* [ %1, %left ], [ %2, %right ]
+  %newload = load i32, i32* %phiptr, align 4
+  %cmp1 = icmp slt i32 %newload, 5
+  br i1 %cmp1, label %left_x, label %right_x
+
+left_x:
+  ret i32 20
+
+right_x:
+  ret i32 10
+}
+
 !0 = !{!3, !3, i64 0}
 !1 = !{!"omnipotent char", !2}
 !2 = !{!"Simple C/C++ TBAA"}