diff --git a/src/libcollections/btree/node.rs b/src/libcollections/btree/node.rs
index bca0e1427e442..4f3c3b0826342 100644
--- a/src/libcollections/btree/node.rs
+++ b/src/libcollections/btree/node.rs
@@ -19,6 +19,8 @@ pub use self::TraversalItem::*;
 use core::prelude::*;
 
 use core::cmp::Ordering::{Greater, Less, Equal};
+#[cfg(not(stage0))]
+use core::intrinsics::arith_offset;
 use core::iter::Zip;
 use core::marker::PhantomData;
 use core::ops::{Deref, DerefMut, Index, IndexMut};
@@ -205,6 +207,7 @@ impl<T> RawItems<T> {
         RawItems::from_parts(slice.as_ptr(), slice.len())
     }
 
+    #[cfg(stage0)]
     unsafe fn from_parts(ptr: *const T, len: usize) -> RawItems<T> {
         if mem::size_of::<T>() == 0 {
             RawItems {
@@ -219,6 +222,22 @@ impl<T> RawItems<T> {
         }
     }
 
+    #[cfg(not(stage0))]
+    unsafe fn from_parts(ptr: *const T, len: usize) -> RawItems<T> {
+        if mem::size_of::<T>() == 0 {
+            RawItems {
+                head: ptr,
+                tail: arith_offset(ptr as *const i8, len as isize) as *const T,
+            }
+        } else {
+            RawItems {
+                head: ptr,
+                tail: ptr.offset(len as isize),
+            }
+        }
+    }
+
+    #[cfg(stage0)]
     unsafe fn push(&mut self, val: T) {
         ptr::write(self.tail as *mut T, val);
 
@@ -228,11 +247,23 @@ impl<T> RawItems<T> {
             self.tail = self.tail.offset(1);
         }
     }
+
+    #[cfg(not(stage0))]
+    unsafe fn push(&mut self, val: T) {
+        ptr::write(self.tail as *mut T, val);
+
+        if mem::size_of::<T>() == 0 {
+            self.tail = arith_offset(self.tail as *const i8, 1) as *const T;
+        } else {
+            self.tail = self.tail.offset(1);
+        }
+    }
 }
 
 impl<T> Iterator for RawItems<T> {
     type Item = T;
 
+    #[cfg(stage0)]
     fn next(&mut self) -> Option<T> {
         if self.head == self.tail {
             None
@@ -250,9 +281,29 @@ impl<T> Iterator for RawItems<T> {
             }
         }
     }
+
+    #[cfg(not(stage0))]
+    fn next(&mut self) -> Option<T> {
+        if self.head == self.tail {
+            None
+        } else {
+            unsafe {
+                let ret = Some(ptr::read(self.head));
+
+                if mem::size_of::<T>() == 0 {
+                    self.head = arith_offset(self.head as *const i8, 1) as *const T;
+                } else {
+                    self.head = self.head.offset(1);
+                }
+
+                ret
+            }
+        }
+    }
 }
 
 impl<T> DoubleEndedIterator for RawItems<T> {
+    #[cfg(stage0)]
     fn next_back(&mut self) -> Option<T> {
         if self.head == self.tail {
             None
@@ -268,6 +319,23 @@ impl<T> DoubleEndedIterator for RawItems<T> {
             }
         }
     }
+
+    #[cfg(not(stage0))]
+    fn next_back(&mut self) -> Option<T> {
+        if self.head == self.tail {
+            None
+        } else {
+            unsafe {
+                if mem::size_of::<T>() == 0 {
+                    self.tail = arith_offset(self.tail as *const i8, -1) as *const T;
+                } else {
+                    self.tail = self.tail.offset(-1);
+                }
+
+                Some(ptr::read(self.tail))
+            }
+        }
+    }
 }
 
 impl<T> Drop for RawItems<T> {
diff --git a/src/libcollections/vec.rs b/src/libcollections/vec.rs
index e35d81d3996b3..d3315758df04b 100644
--- a/src/libcollections/vec.rs
+++ b/src/libcollections/vec.rs
@@ -66,6 +66,8 @@ use core::cmp::Ordering;
 use core::fmt;
 use core::hash::{self, Hash};
 use core::intrinsics::assume;
+#[cfg(not(stage0))]
+use core::intrinsics::arith_offset;
 use core::iter::{repeat, FromIterator};
 use core::marker::PhantomData;
 use core::mem;
@@ -1527,6 +1529,7 @@ impl<T> IntoIterator for Vec<T> {
     /// }
     /// ```
     #[inline]
+    #[cfg(stage0)]
     fn into_iter(self) -> IntoIter<T> {
         unsafe {
             let ptr = *self.ptr;
@@ -1542,6 +1545,24 @@ impl<T> IntoIterator for Vec<T> {
             IntoIter { allocation: ptr, cap: cap, ptr: begin, end: end }
         }
     }
+
+    #[inline]
+    #[cfg(not(stage0))]
+    fn into_iter(self) -> IntoIter<T> {
+        unsafe {
+            let ptr = *self.ptr;
+            assume(!ptr.is_null());
+            let cap = self.cap;
+            let begin = ptr as *const T;
+            let end = if mem::size_of::<T>() == 0 {
+                arith_offset(ptr as *const i8, self.len() as isize) as *const T
+            } else {
+                ptr.offset(self.len() as isize) as *const T
+            };
+            mem::forget(self);
+            IntoIter { allocation: ptr, cap: cap, ptr: begin, end: end }
+        }
+    }
 }
 
 #[stable(feature = "rust1", since = "1.0.0")]
@@ -1746,6 +1767,7 @@ impl<T> Iterator for IntoIter<T> {
     type Item = T;
 
     #[inline]
+    #[cfg(stage0)]
     fn next(&mut self) -> Option<T> {
         unsafe {
             if self.ptr == self.end {
@@ -1769,6 +1791,31 @@ impl<T> Iterator for IntoIter<T> {
         }
     }
 
+    #[inline]
+    #[cfg(not(stage0))]
+    fn next(&mut self) -> Option<T> {
+        unsafe {
+            if self.ptr == self.end {
+                None
+            } else {
+                if mem::size_of::<T>() == 0 {
+                    // purposefully don't use 'ptr.offset' because for
+                    // vectors with 0-size elements this would return the
+                    // same pointer.
+                    self.ptr = arith_offset(self.ptr as *const i8, 1) as *const T;
+
+                    // Use a non-null pointer value
+                    Some(ptr::read(EMPTY as *mut T))
+                } else {
+                    let old = self.ptr;
+                    self.ptr = self.ptr.offset(1);
+
+                    Some(ptr::read(old))
+                }
+            }
+        }
+    }
+
     #[inline]
     fn size_hint(&self) -> (usize, Option<usize>) {
         let diff = (self.end as usize) - (self.ptr as usize);
@@ -1786,6 +1833,7 @@ impl<T> Iterator for IntoIter<T> {
 #[stable(feature = "rust1", since = "1.0.0")]
 impl<T> DoubleEndedIterator for IntoIter<T> {
     #[inline]
+    #[cfg(stage0)]
     fn next_back(&mut self) -> Option<T> {
         unsafe {
             if self.end == self.ptr {
@@ -1805,6 +1853,28 @@ impl<T> DoubleEndedIterator for IntoIter<T> {
             }
         }
     }
+
+    #[inline]
+    #[cfg(not(stage0))]
+    fn next_back(&mut self) -> Option<T> {
+        unsafe {
+            if self.end == self.ptr {
+                None
+            } else {
+                if mem::size_of::<T>() == 0 {
+                    // See above for why 'ptr.offset' isn't used
+                    self.end = arith_offset(self.end as *const i8, -1) as *const T;
+
+                    // Use a non-null pointer value
+                    Some(ptr::read(EMPTY as *mut T))
+                } else {
+                    self.end = self.end.offset(-1);
+
+                    Some(ptr::read(mem::transmute(self.end)))
+                }
+            }
+        }
+    }
 }
 
 #[stable(feature = "rust1", since = "1.0.0")]
diff --git a/src/libcore/intrinsics.rs b/src/libcore/intrinsics.rs
index d94b8884112d6..fa432e311eb74 100644
--- a/src/libcore/intrinsics.rs
+++ b/src/libcore/intrinsics.rs
@@ -283,6 +283,20 @@ extern "rust-intrinsic" {
     /// returned value will result in undefined behavior.
     pub fn offset<T>(dst: *const T, offset: isize) -> *const T;
 
+    /// Calculates the offset from a pointer, potentially wrapping.
+    ///
+    /// This is implemented as an intrinsic to avoid converting to and from an
+    /// integer, since the conversion inhibits certain optimizations.
+    ///
+    /// # Safety
+    ///
+    /// Unlike the `offset` intrinsic, this intrinsic does not restrict the
+    /// resulting pointer to point into or one byte past the end of an allocated
+    /// object, and it wraps with two's complement arithmetic. The resulting
+    /// value is not necessarily valid to be used to actually access memory.
+    #[cfg(not(stage0))]
+    pub fn arith_offset<T>(dst: *const T, offset: isize) -> *const T;
+
     /// Copies `count * size_of<T>` bytes from `src` to `dst`. The source
     /// and destination may *not* overlap.
     ///
diff --git a/src/libcore/slice.rs b/src/libcore/slice.rs
index 546e0bc806e12..cbac70921b7ee 100644
--- a/src/libcore/slice.rs
+++ b/src/libcore/slice.rs
@@ -124,6 +124,43 @@ pub trait SliceExt {
     fn clone_from_slice(&mut self, &[Self::Item]) -> usize where Self::Item: Clone;
 }
 
+// Use macros to be generic over const/mut
+#[cfg(stage0)]
+macro_rules! slice_offset {
+    ($ptr:expr, $by:expr) => {{
+        let ptr = $ptr;
+        if size_from_ptr(ptr) == 0 {
+            transmute((ptr as isize).wrapping_add($by))
+        } else {
+            ptr.offset($by)
+        }
+    }};
+}
+
+#[cfg(not(stage0))]
+macro_rules! slice_offset {
+    ($ptr:expr, $by:expr) => {{
+        let ptr = $ptr;
+        if size_from_ptr(ptr) == 0 {
+            ::intrinsics::arith_offset(ptr as *mut i8, $by) as *mut _
+        } else {
+            ptr.offset($by)
+        }
+    }};
+}
+
+macro_rules! slice_ref {
+    ($ptr:expr) => {{
+        let ptr = $ptr;
+        if size_from_ptr(ptr) == 0 {
+            // Use a non-null pointer value
+            &mut *(1 as *mut _)
+        } else {
+            transmute(ptr)
+        }
+    }};
+}
+
 #[unstable(feature = "core")]
 impl<T> SliceExt for [T] {
     type Item = T;
@@ -136,16 +173,18 @@ impl<T> SliceExt for [T] {
     #[inline]
     fn iter<'a>(&'a self) -> Iter<'a, T> {
         unsafe {
-            let p = self.as_ptr();
-            assume(!p.is_null());
-            if mem::size_of::<T>() == 0 {
-                Iter {ptr: p,
-                      end: ((p as usize).wrapping_add(self.len())) as *const T,
-                      _marker: marker::PhantomData}
+            let p = if mem::size_of::<T>() == 0 {
+                1 as *const _
             } else {
-                Iter {ptr: p,
-                      end: p.offset(self.len() as isize),
-                      _marker: marker::PhantomData}
+                let p = self.as_ptr();
+                assume(!p.is_null());
+                p
+            };
+
+            Iter {
+                ptr: p,
+                end: slice_offset!(p, self.len() as isize),
+                _marker: marker::PhantomData
             }
         }
     }
@@ -273,16 +312,18 @@ impl<T> SliceExt for [T] {
     #[inline]
     fn iter_mut<'a>(&'a mut self) -> IterMut<'a, T> {
         unsafe {
-            let p = self.as_mut_ptr();
-            assume(!p.is_null());
-            if mem::size_of::<T>() == 0 {
-                IterMut {ptr: p,
-                         end: ((p as usize).wrapping_add(self.len())) as *mut T,
-                         _marker: marker::PhantomData}
+            let p = if mem::size_of::<T>() == 0 {
+                1 as *mut _
             } else {
-                IterMut {ptr: p,
-                         end: p.offset(self.len() as isize),
-                         _marker: marker::PhantomData}
+                let p = self.as_mut_ptr();
+                assume(!p.is_null());
+                p
+            };
+
+            IterMut {
+                ptr: p,
+                end: slice_offset!(p, self.len() as isize),
+                _marker: marker::PhantomData
             }
         }
     }
@@ -630,31 +671,6 @@ fn size_from_ptr<T>(_: *const T) -> usize {
     mem::size_of::<T>()
 }
 
-
-// Use macros to be generic over const/mut
-macro_rules! slice_offset {
-    ($ptr:expr, $by:expr) => {{
-        let ptr = $ptr;
-        if size_from_ptr(ptr) == 0 {
-            transmute((ptr as isize).wrapping_add($by))
-        } else {
-            ptr.offset($by)
-        }
-    }};
-}
-
-macro_rules! slice_ref {
-    ($ptr:expr) => {{
-        let ptr = $ptr;
-        if size_from_ptr(ptr) == 0 {
-            // Use a non-null pointer value
-            &mut *(1 as *mut _)
-        } else {
-            transmute(ptr)
-        }
-    }};
-}
-
 // The shared definition of the `Iter` and `IterMut` iterators
 macro_rules! iterator {
     (struct $name:ident -> $ptr:ty, $elem:ty) => {
@@ -781,7 +797,7 @@ impl<'a, T> Iter<'a, T> {
         match self.as_slice().get(n) {
             Some(elem_ref) => unsafe {
                 self.ptr = slice_offset!(self.ptr, (n as isize).wrapping_add(1));
-                Some(slice_ref!(elem_ref))
+                Some(elem_ref)
             },
             None => {
                 self.ptr = self.end;
@@ -849,7 +865,7 @@ impl<'a, T> IterMut<'a, T> {
         match make_mut_slice!(self.ptr, self.end).get_mut(n) {
             Some(elem_ref) => unsafe {
                 self.ptr = slice_offset!(self.ptr, (n as isize).wrapping_add(1));
-                Some(slice_ref!(elem_ref))
+                Some(elem_ref)
             },
             None => {
                 self.ptr = self.end;
diff --git a/src/librustc_trans/trans/intrinsic.rs b/src/librustc_trans/trans/intrinsic.rs
index 951d30c4fb8db..4608918ec59bd 100644
--- a/src/librustc_trans/trans/intrinsic.rs
+++ b/src/librustc_trans/trans/intrinsic.rs
@@ -418,6 +418,11 @@ pub fn trans_intrinsic_call<'a, 'blk, 'tcx>(mut bcx: Block<'blk, 'tcx>,
             let offset = llargs[1];
             InBoundsGEP(bcx, ptr, &[offset])
         }
+        (_, "arith_offset") => {
+            let ptr = llargs[0];
+            let offset = llargs[1];
+            GEP(bcx, ptr, &[offset])
+        }
 
         (_, "copy_nonoverlapping") => {
             copy_intrinsic(bcx,
diff --git a/src/librustc_typeck/check/mod.rs b/src/librustc_typeck/check/mod.rs
index 3cdbaec15284b..f13305bba343e 100644
--- a/src/librustc_typeck/check/mod.rs
+++ b/src/librustc_typeck/check/mod.rs
@@ -5009,7 +5009,7 @@ pub fn check_intrinsic_type(ccx: &CrateCtxt, it: &ast::ForeignItem) {
             "type_name" => (1, Vec::new(), ty::mk_str_slice(tcx, tcx.mk_region(ty::ReStatic),
                                                              ast::MutImmutable)),
             "type_id" => (1, Vec::new(), ccx.tcx.types.u64),
-            "offset" => {
+            "offset" | "arith_offset" => {
               (1,
                vec!(
                   ty::mk_ptr(tcx, ty::mt {