Index: llvm/trunk/lib/Analysis/InstructionSimplify.cpp
===================================================================
--- llvm/trunk/lib/Analysis/InstructionSimplify.cpp
+++ llvm/trunk/lib/Analysis/InstructionSimplify.cpp
@@ -3723,7 +3723,7 @@
 
   if (Ops.size() == 2) {
     // getelementptr P, 0 -> P.
-    if (match(Ops[1], m_Zero()))
+    if (match(Ops[1], m_Zero()) && Ops[0]->getType() == GEPTy)
       return Ops[0];
 
     Type *Ty = SrcTy;
@@ -3732,7 +3732,7 @@
       uint64_t C;
       uint64_t TyAllocSize = Q.DL.getTypeAllocSize(Ty);
       // getelementptr P, N -> P if P points to a type of zero size.
-      if (TyAllocSize == 0)
+      if (TyAllocSize == 0 && Ops[0]->getType() == GEPTy)
         return Ops[0];
 
       // The following transforms are only safe if the ptrtoint cast
Index: llvm/trunk/lib/IR/ConstantFold.cpp
===================================================================
--- llvm/trunk/lib/IR/ConstantFold.cpp
+++ llvm/trunk/lib/IR/ConstantFold.cpp
@@ -2027,8 +2027,16 @@
 
   // If the first index is one and all the rest are zero, it's in bounds,
   // by the one-past-the-end rule.
-  if (!cast<ConstantInt>(Idxs[0])->isOne())
-    return false;
+  if (auto *CI = dyn_cast<ConstantInt>(Idxs[0])) {
+    if (!CI->isOne())
+      return false;
+  } else {
+    auto *CV = cast<ConstantDataVector>(Idxs[0]);
+    CI = dyn_cast_or_null<ConstantInt>(CV->getSplatValue());
+    if (!CI || !CI->isOne())
+      return false;
+  }
+
   for (unsigned i = 1, e = Idxs.size(); i != e; ++i)
     if (!cast<Constant>(Idxs[i])->isNullValue())
       return false;
@@ -2058,15 +2066,18 @@
                                           ArrayRef<Value *> Idxs) {
   if (Idxs.empty()) return C;
 
-  if (isa<UndefValue>(C)) {
-    Type *GEPTy = GetElementPtrInst::getGEPReturnType(
-        C, makeArrayRef((Value * const *)Idxs.data(), Idxs.size()));
+  Type *GEPTy = GetElementPtrInst::getGEPReturnType(
+      C, makeArrayRef((Value *const *)Idxs.data(), Idxs.size()));
+
+  if (isa<UndefValue>(C))
     return UndefValue::get(GEPTy);
-  }
 
   Constant *Idx0 = cast<Constant>(Idxs[0]);
   if (Idxs.size() == 1 && (Idx0->isNullValue() || isa<UndefValue>(Idx0)))
-    return C;
+    return GEPTy->isVectorTy() && !C->getType()->isVectorTy()
+               ? ConstantVector::getSplat(
+                     cast<VectorType>(GEPTy)->getNumElements(), C)
+               : C;
 
   if (C->isNullValue()) {
     bool isNull = true;
Index: llvm/trunk/test/Analysis/ConstantFolding/vectorgep-crash.ll
===================================================================
--- llvm/trunk/test/Analysis/ConstantFolding/vectorgep-crash.ll
+++ llvm/trunk/test/Analysis/ConstantFolding/vectorgep-crash.ll
@@ -38,3 +38,29 @@
   %VectorGep = getelementptr [65 x %struct.A], [65 x %struct.A]* @G, <16 x i32> zeroinitializer, <16 x i64> <i64 1, i64 2, i64 3, i64 4, i64 5, i64 6, i64 7, i64 8, i64 9, i64 10, i64 11, i64 12, i64 13, i64 14, i64 15, i64 16>, <16 x i32> zeroinitializer
   ret <16 x i32*> %VectorGep
 }
+
+@g = external global i8, align 1
+
+define <2 x i8*> @constant_zero_index() {
+; CHECK-LABEL: @constant_zero_index(
+; CHECK-NEXT:    ret <2 x i8*> <i8* @g, i8* @g>
+;
+  %gep = getelementptr i8, i8* @g, <2 x i64> zeroinitializer
+  ret <2 x i8*> %gep
+}
+
+define <2 x i8*> @constant_undef_index() {
+; CHECK-LABEL: @constant_undef_index(
+; CHECK-NEXT:    ret <2 x i8*> <i8* @g, i8* @g>
+;
+  %gep = getelementptr i8, i8* @g, <2 x i64> undef
+  ret <2 x i8*> %gep
+}
+
+define <2 x i8*> @constant_inbounds() {
+; CHECK-LABEL: @constant_inbounds(
+; CHECK-NEXT:    ret <2 x i8*> getelementptr inbounds (i8, i8* @g, <2 x i64> <i64 1, i64 1>)
+;
+  %gep = getelementptr i8, i8* @g, <2 x i64> <i64 1, i64 1>
+  ret <2 x i8*> %gep
+}
Index: llvm/trunk/test/Transforms/InstSimplify/vector_gep.ll
===================================================================
--- llvm/trunk/test/Transforms/InstSimplify/vector_gep.ll
+++ llvm/trunk/test/Transforms/InstSimplify/vector_gep.ll
@@ -86,3 +86,21 @@
   %patatino = getelementptr i8, <4 x i8 *> undef, i64 undef
   ret <4 x i8*> %patatino
 }
+
+define <2 x i8*> @zero_index(i8* %p) {
+; CHECK-LABEL: @zero_index(
+; CHECK-NEXT:    %gep = getelementptr i8, i8* %p, <2 x i64> zeroinitializer
+; CHECK-NEXT:    ret <2 x i8*> %gep
+;
+  %gep = getelementptr i8, i8* %p, <2 x i64> zeroinitializer
+  ret <2 x i8*> %gep
+}
+
+define <2 x {}*> @unsized({}* %p) {
+; CHECK-LABEL: @unsized(
+; CHECK-NEXT:    %gep = getelementptr {}, {}* %p, <2 x i64> undef
+; CHECK-NEXT:    ret <2 x {}*> %gep
+;
+  %gep = getelementptr {}, {}* %p, <2 x i64> undef
+  ret <2 x {}*> %gep
+}