Index: ../lib/Transforms/Vectorize/LoopVectorize.cpp
===================================================================
--- ../lib/Transforms/Vectorize/LoopVectorize.cpp
+++ ../lib/Transforms/Vectorize/LoopVectorize.cpp
@@ -254,16 +254,29 @@
   return VectorType::get(Scalar, VF);
 }
 
-/// A helper function that returns GEP instruction and knows to skip
-/// 'bitcast'.
+/// A helper function that returns GEP instruction and knows to skip a
+/// 'bitcast'. The 'bitcast' may be skipped if the source and the destination
+/// pointee types of the 'bitcast' have the same size.
+/// For example:
+///   bitcast double** %var to i64* - can be skipped
+///   bitcast double** %var to i8*  - can not
 static GetElementPtrInst *getGEPInstruction(Value *Ptr) {
 
   if (isa<GetElementPtrInst>(Ptr))
     return cast<GetElementPtrInst>(Ptr);
 
   if (isa<BitCastInst>(Ptr) &&
-      isa<GetElementPtrInst>(cast<BitCastInst>(Ptr)->getOperand(0)))
-    return cast<GetElementPtrInst>(cast<BitCastInst>(Ptr)->getOperand(0));
+      isa<GetElementPtrInst>(cast<BitCastInst>(Ptr)->getOperand(0))) {
+    Type *BitcastTy = Ptr->getType();
+    Type *GEPTy = cast<BitCastInst>(Ptr)->getSrcTy();
+    if (!isa<PointerType>(BitcastTy) || !isa<PointerType>(GEPTy))
+      return nullptr;
+    Type *Pointee1Ty = cast<PointerType>(BitcastTy)->getPointerElementType();
+    Type *Pointee2Ty = cast<PointerType>(GEPTy)->getPointerElementType();
+    const DataLayout &DL = cast<BitCastInst>(Ptr)->getModule()->getDataLayout();
+    if (DL.getTypeSizeInBits(Pointee1Ty) == DL.getTypeSizeInBits(Pointee2Ty))
+      return cast<GetElementPtrInst>(cast<BitCastInst>(Ptr)->getOperand(0));
+  }
   return nullptr;
 }
 
Index: ../test/Transforms/LoopVectorize/gep_with_bitcast.ll
===================================================================
--- ../test/Transforms/LoopVectorize/gep_with_bitcast.ll
+++ ../test/Transforms/LoopVectorize/gep_with_bitcast.ll
@@ -37,4 +37,31 @@
 
 for.end:
   ret void
+}
+
+; CHECK-LABEL: @bar
+; CHECK: vector.body
+; CHECK: bitcast double** {{.*}} to i8*
+; CHECK: load i8, i8*
+; CHECK: insertelement <4 x i8> undef, i8 {{.*}}
+
+define void @bar(double** noalias nocapture readonly %in, double** noalias nocapture readnone %out, i8* noalias nocapture %res) #0 {
+entry:
+  br label %for.body
+
+for.body:
+  %indvars.iv = phi i64 [ 0, %entry ], [ %indvars.iv.next, %for.body ]
+  %arrayidx = getelementptr inbounds double*, double** %in, i64 %indvars.iv
+  %tmp53 = bitcast double** %arrayidx to i8*
+  %tmp54 = load i8, i8* %tmp53, align 1
+  %cmp1 = icmp eq i8 %tmp54, 0
+  %arrayidx3 = getelementptr inbounds i8, i8* %res, i64 %indvars.iv
+  %frombool = zext i1 %cmp1 to i8
+  store i8 %frombool, i8* %arrayidx3, align 1
+  %indvars.iv.next = add nuw nsw i64 %indvars.iv, 1
+  %exitcond = icmp eq i64 %indvars.iv.next, 4096
+  br i1 %exitcond, label %for.end, label %for.body
+
+for.end:
+  ret void
 }
\ No newline at end of file