diff --git a/src/librustc/middle/ty.rs b/src/librustc/middle/ty.rs
index 733fa0e71b4..d54271b7531 100644
--- a/src/librustc/middle/ty.rs
+++ b/src/librustc/middle/ty.rs
@@ -3179,11 +3179,12 @@ impl<'tcx> TraitDef<'tcx> {
 bitflags! {
     flags ADTFlags: u32 {
         const NO_ADT_FLAGS        = 0,
-        const IS_FUNDAMENTAL      = 1 << 0,
-        const IS_PHANTOM_DATA     = 1 << 1,
-        const IS_DTORCK           = 1 << 2, // is this a dtorck type?
-        const IS_DTORCK_VALID     = 1 << 3,
-        const IS_ENUM             = 1 << 4
+        const IS_ENUM             = 1 << 0,
+        const IS_DTORCK           = 1 << 1, // is this a dtorck type?
+        const IS_DTORCK_VALID     = 1 << 2,
+        const IS_PHANTOM_DATA     = 1 << 3,
+        const IS_SIMD             = 1 << 4,
+        const IS_FUNDAMENTAL      = 1 << 5,
     }
 }
 
@@ -3244,9 +3245,13 @@ impl<'tcx, 'lt> ADTDef_<'tcx, 'lt> {
            kind: ADTKind,
            variants: Vec<VariantDef_<'tcx, 'lt>>) -> Self {
         let mut flags = ADTFlags::NO_ADT_FLAGS;
-        if tcx.has_attr(did, "fundamental") {
+        let attrs = tcx.get_attrs(did);
+        if attrs.iter().any(|item| item.check_name("fundamental")) {
             flags = flags | ADTFlags::IS_FUNDAMENTAL;
         }
+        if attrs.iter().any(|item| item.check_name("simd")) {
+            flags = flags | ADTFlags::IS_SIMD;
+        }
         if Some(did) == tcx.lang_items.phantom_data() {
             flags = flags | ADTFlags::IS_PHANTOM_DATA;
         }
@@ -3289,6 +3294,11 @@ impl<'tcx, 'lt> ADTDef_<'tcx, 'lt> {
         self.flags.get().intersects(ADTFlags::IS_FUNDAMENTAL)
     }
 
+    #[inline]
+    pub fn is_simd(&self) -> bool {
+        self.flags.get().intersects(ADTFlags::IS_SIMD)
+    }
+
     #[inline]
     pub fn is_phantom_data(&self) -> bool {
         self.flags.get().intersects(ADTFlags::IS_PHANTOM_DATA)
@@ -4203,9 +4213,10 @@ impl<'tcx> TyS<'tcx> {
         }
     }
 
-    pub fn is_simd(&self, cx: &ctxt) -> bool {
+    #[inline]
+    pub fn is_simd(&self) -> bool {
         match self.sty {
-            TyStruct(def, _) => cx.lookup_simd(def.did),
+            TyStruct(def, _) => def.is_simd(),
             _ => false
         }
     }
@@ -5979,7 +5990,6 @@ impl<'tcx> ctxt<'tcx> {
 
     /// Obtain the representation annotation for a struct definition.
     pub fn lookup_repr_hints(&self, did: DefId) -> Rc<Vec<attr::ReprAttr>> {
-        // TODO: remove
         memoized(&self.repr_hint_cache, did, |did: DefId| {
             Rc::new(if did.krate == LOCAL_CRATE {
                 self.get_attrs(did).iter().flat_map(|meta| {
diff --git a/src/librustc_trans/trans/base.rs b/src/librustc_trans/trans/base.rs
index d119e0006c6..a0dd489cd8a 100644
--- a/src/librustc_trans/trans/base.rs
+++ b/src/librustc_trans/trans/base.rs
@@ -621,7 +621,7 @@ pub fn fail_if_zero_or_overflows<'blk, 'tcx>(
             let zero = C_integral(Type::uint_from_ty(cx.ccx(), t), 0, false);
             (ICmp(cx, llvm::IntEQ, rhs, zero, debug_loc), false)
         }
-        ty::TyStruct(_, _) if rhs_t.is_simd(cx.tcx()) => {
+        ty::TyStruct(def, _) if def.is_simd() => {
             let mut res = C_bool(cx.ccx(), false);
             for i in 0 .. rhs_t.simd_size(cx.tcx()) {
                 res = Or(cx, res,
diff --git a/src/librustc_trans/trans/common.rs b/src/librustc_trans/trans/common.rs
index 15c81b114d3..7bc6f4c8fe9 100644
--- a/src/librustc_trans/trans/common.rs
+++ b/src/librustc_trans/trans/common.rs
@@ -192,7 +192,7 @@ pub fn type_is_immediate<'a, 'tcx>(ccx: &CrateContext<'a, 'tcx>, ty: Ty<'tcx>) -
     let simple = ty.is_scalar() ||
         ty.is_unique() || ty.is_region_ptr() ||
         type_is_newtype_immediate(ccx, ty) ||
-        ty.is_simd(tcx);
+        ty.is_simd();
     if simple && !type_is_fat_ptr(tcx, ty) {
         return true;
     }
diff --git a/src/librustc_trans/trans/consts.rs b/src/librustc_trans/trans/consts.rs
index 7a9ddf5a99c..7aaed035f21 100644
--- a/src/librustc_trans/trans/consts.rs
+++ b/src/librustc_trans/trans/consts.rs
@@ -500,7 +500,7 @@ fn const_expr_unadjusted<'a, 'tcx>(cx: &CrateContext<'a, 'tcx>,
             debug!("const_expr_unadjusted: te1={}, ty={:?}",
                    cx.tn().val_to_string(te1),
                    ty);
-            let is_simd = ty.is_simd(cx.tcx());
+            let is_simd = ty.is_simd();
             let intype = if is_simd {
                 ty.simd_type(cx.tcx())
             } else {
@@ -754,7 +754,7 @@ fn const_expr_unadjusted<'a, 'tcx>(cx: &CrateContext<'a, 'tcx>,
                     (_, None) => cx.sess().span_bug(e.span, "missing struct field"),
                 }
             }).collect::<Vec<_>>();
-            if ety.is_simd(cx.tcx()) {
+            if ety.is_simd() {
                 C_vector(&cs[..])
             } else {
                 adt::trans_const(cx, &*repr, discr, &cs[..])
@@ -850,7 +850,7 @@ fn const_expr_unadjusted<'a, 'tcx>(cx: &CrateContext<'a, 'tcx>,
                     const_fn_call(cx, ExprId(callee.id), did, &arg_vals, param_substs)
                 }
                 def::DefStruct(_) => {
-                    if ety.is_simd(cx.tcx()) {
+                    if ety.is_simd() {
                         C_vector(&arg_vals[..])
                     } else {
                         let repr = adt::represent_type(cx, ety);
diff --git a/src/librustc_trans/trans/debuginfo/metadata.rs b/src/librustc_trans/trans/debuginfo/metadata.rs
index 98188a40e10..3ca639cc367 100644
--- a/src/librustc_trans/trans/debuginfo/metadata.rs
+++ b/src/librustc_trans/trans/debuginfo/metadata.rs
@@ -1175,7 +1175,7 @@ fn prepare_struct_metadata<'a, 'tcx>(cx: &CrateContext<'a, 'tcx>,
         StructMDF(StructMemberDescriptionFactory {
             variant: variant,
             substs: substs,
-            is_simd: struct_type.is_simd(cx.tcx()),
+            is_simd: struct_type.is_simd(),
             span: span,
         })
     )
diff --git a/src/librustc_trans/trans/expr.rs b/src/librustc_trans/trans/expr.rs
index baf14df5b80..c5043f867de 100644
--- a/src/librustc_trans/trans/expr.rs
+++ b/src/librustc_trans/trans/expr.rs
@@ -1453,7 +1453,7 @@ pub fn trans_adt<'a, 'blk, 'tcx>(mut bcx: Block<'blk, 'tcx>,
     // panic occur before the ADT as a whole is ready.
     let custom_cleanup_scope = fcx.push_custom_cleanup_scope();
 
-    if ty.is_simd(bcx.tcx()) {
+    if ty.is_simd() {
         // Issue 23112: The original logic appeared vulnerable to same
         // order-of-eval bug. But, SIMD values are tuple-structs;
         // i.e. functional record update (FRU) syntax is unavailable.
@@ -1697,7 +1697,7 @@ fn trans_eager_binop<'blk, 'tcx>(bcx: Block<'blk, 'tcx>,
     let _icx = push_ctxt("trans_eager_binop");
 
     let tcx = bcx.tcx();
-    let is_simd = lhs_t.is_simd(tcx);
+    let is_simd = lhs_t.is_simd();
     let intype = if is_simd {
         lhs_t.simd_type(tcx)
     } else {
@@ -2502,7 +2502,7 @@ fn build_unchecked_rshift<'blk, 'tcx>(bcx: Block<'blk, 'tcx>,
     // #1877, #10183: Ensure that input is always valid
     let rhs = shift_mask_rhs(bcx, rhs, binop_debug_loc);
     let tcx = bcx.tcx();
-    let is_simd = lhs_t.is_simd(tcx);
+    let is_simd = lhs_t.is_simd();
     let intype = if is_simd {
         lhs_t.simd_type(tcx)
     } else {
diff --git a/src/librustc_trans/trans/foreign.rs b/src/librustc_trans/trans/foreign.rs
index cafc0be74ba..225ff52a63c 100644
--- a/src/librustc_trans/trans/foreign.rs
+++ b/src/librustc_trans/trans/foreign.rs
@@ -449,7 +449,7 @@ pub fn trans_native_call<'blk, 'tcx>(bcx: Block<'blk, 'tcx>,
 fn gate_simd_ffi(tcx: &ty::ctxt, decl: &ast::FnDecl, ty: &ty::BareFnTy) {
     if !tcx.sess.features.borrow().simd_ffi {
         let check = |ast_ty: &ast::Ty, ty: ty::Ty| {
-            if ty.is_simd(tcx) {
+            if ty.is_simd() {
                 tcx.sess.span_err(ast_ty.span,
                               &format!("use of SIMD type `{}` in FFI is highly experimental and \
                                         may result in invalid code",
diff --git a/src/librustc_trans/trans/glue.rs b/src/librustc_trans/trans/glue.rs
index 30cf6f519fb..cf3cde8907f 100644
--- a/src/librustc_trans/trans/glue.rs
+++ b/src/librustc_trans/trans/glue.rs
@@ -419,7 +419,7 @@ pub fn size_and_align_of_dst<'blk, 'tcx>(bcx: Block<'blk, 'tcx>, t: Ty<'tcx>, in
             let ccx = bcx.ccx();
             // First get the size of all statically known fields.
             // Don't use type_of::sizing_type_of because that expects t to be sized.
-            assert!(!t.is_simd(bcx.tcx()));
+            assert!(!t.is_simd());
             let repr = adt::represent_type(ccx, t);
             let sizing_type = adt::sizing_type_context_of(ccx, &*repr, true);
             debug!("DST {} sizing_type: {}", t, sizing_type.to_string());
diff --git a/src/librustc_trans/trans/type_of.rs b/src/librustc_trans/trans/type_of.rs
index 91247ebd791..0b969360f53 100644
--- a/src/librustc_trans/trans/type_of.rs
+++ b/src/librustc_trans/trans/type_of.rs
@@ -222,7 +222,7 @@ pub fn sizing_type_of<'a, 'tcx>(cx: &CrateContext<'a, 'tcx>, t: Ty<'tcx>) -> Typ
         }
 
         ty::TyStruct(..) => {
-            if t.is_simd(cx.tcx()) {
+            if t.is_simd() {
                 let llet = type_of(cx, t.simd_type(cx.tcx()));
                 let n = t.simd_size(cx.tcx()) as u64;
                 ensure_array_fits_in_address_space(cx, llet, n, t);
@@ -404,7 +404,7 @@ pub fn in_memory_type_of<'a, 'tcx>(cx: &CrateContext<'a, 'tcx>, t: Ty<'tcx>) ->
           adt::type_of(cx, &*repr)
       }
       ty::TyStruct(def, ref substs) => {
-          if t.is_simd(cx.tcx()) {
+          if t.is_simd() {
               let llet = in_memory_type_of(cx, t.simd_type(cx.tcx()));
               let n = t.simd_size(cx.tcx()) as u64;
               ensure_array_fits_in_address_space(cx, llet, n, t);
@@ -436,7 +436,7 @@ pub fn in_memory_type_of<'a, 'tcx>(cx: &CrateContext<'a, 'tcx>, t: Ty<'tcx>) ->
     // If this was an enum or struct, fill in the type now.
     match t.sty {
         ty::TyEnum(..) | ty::TyStruct(..) | ty::TyClosure(..)
-                if !t.is_simd(cx.tcx()) => {
+                if !t.is_simd() => {
             let repr = adt::represent_type(cx, t);
             adt::finish_type_of(cx, &*repr, &mut llty);
         }
diff --git a/src/librustc_typeck/check/op.rs b/src/librustc_typeck/check/op.rs
index c6d13d3b0a5..b139cb45bf2 100644
--- a/src/librustc_typeck/check/op.rs
+++ b/src/librustc_typeck/check/op.rs
@@ -21,7 +21,7 @@ use super::{
     structurally_resolved_type,
 };
 use middle::traits;
-use middle::ty::{self, Ty, HasTypeFlags};
+use middle::ty::{Ty, HasTypeFlags};
 use syntax::ast;
 use syntax::ast_util;
 use syntax::parse::token;
@@ -41,7 +41,7 @@ pub fn check_binop_assign<'a,'tcx>(fcx: &FnCtxt<'a,'tcx>,
     let lhs_ty = structurally_resolved_type(fcx, lhs_expr.span, fcx.expr_ty(lhs_expr));
     let rhs_ty = structurally_resolved_type(fcx, rhs_expr.span, fcx.expr_ty(rhs_expr));
 
-    if is_builtin_binop(fcx.tcx(), lhs_ty, rhs_ty, op) {
+    if is_builtin_binop(lhs_ty, rhs_ty, op) {
         enforce_builtin_binop_types(fcx, lhs_expr, lhs_ty, rhs_expr, rhs_ty, op);
         fcx.write_nil(expr.id);
     } else {
@@ -86,7 +86,7 @@ pub fn check_binop<'a, 'tcx>(fcx: &FnCtxt<'a, 'tcx>,
     // traits, because their return type is not bool. Perhaps this
     // should change, but for now if LHS is SIMD we go down a
     // different path that bypassess all traits.
-    if lhs_ty.is_simd(fcx.tcx()) {
+    if lhs_ty.is_simd() {
         check_expr_coercable_to_type(fcx, rhs_expr, lhs_ty);
         let rhs_ty = fcx.resolve_type_vars_if_possible(fcx.expr_ty(lhs_expr));
         let return_ty = enforce_builtin_binop_types(fcx, lhs_expr, lhs_ty, rhs_expr, rhs_ty, op);
@@ -123,7 +123,7 @@ pub fn check_binop<'a, 'tcx>(fcx: &FnCtxt<'a, 'tcx>,
             let rhs_ty = fcx.resolve_type_vars_if_possible(rhs_ty);
             if
                 !lhs_ty.is_ty_var() && !rhs_ty.is_ty_var() &&
-                is_builtin_binop(fcx.tcx(), lhs_ty, rhs_ty, op)
+                is_builtin_binop(lhs_ty, rhs_ty, op)
             {
                 let builtin_return_ty =
                     enforce_builtin_binop_types(fcx, lhs_expr, lhs_ty, rhs_expr, rhs_ty, op);
@@ -143,7 +143,7 @@ fn enforce_builtin_binop_types<'a, 'tcx>(fcx: &FnCtxt<'a, 'tcx>,
                                          op: ast::BinOp)
                                          -> Ty<'tcx>
 {
-    debug_assert!(is_builtin_binop(fcx.tcx(), lhs_ty, rhs_ty, op));
+    debug_assert!(is_builtin_binop(lhs_ty, rhs_ty, op));
 
     let tcx = fcx.tcx();
     match BinOpCategory::from(op) {
@@ -156,7 +156,7 @@ fn enforce_builtin_binop_types<'a, 'tcx>(fcx: &FnCtxt<'a, 'tcx>,
         BinOpCategory::Shift => {
             // For integers, the shift amount can be of any integral
             // type. For simd, the type must match exactly.
-            if lhs_ty.is_simd(tcx) {
+            if lhs_ty.is_simd() {
                 demand::suptype(fcx, rhs_expr.span, lhs_ty, rhs_ty);
             }
 
@@ -176,7 +176,7 @@ fn enforce_builtin_binop_types<'a, 'tcx>(fcx: &FnCtxt<'a, 'tcx>,
             demand::suptype(fcx, rhs_expr.span, lhs_ty, rhs_ty);
 
             // if this is simd, result is same as lhs, else bool
-            if lhs_ty.is_simd(tcx) {
+            if lhs_ty.is_simd() {
                 let unit_ty = lhs_ty.simd_type(tcx);
                 debug!("enforce_builtin_binop_types: lhs_ty={:?} unit_ty={:?}",
                        lhs_ty,
@@ -415,8 +415,7 @@ impl BinOpCategory {
 /// Reason #2 is the killer. I tried for a while to always use
 /// overloaded logic and just check the types in constants/trans after
 /// the fact, and it worked fine, except for SIMD types. -nmatsakis
-fn is_builtin_binop<'tcx>(cx: &ty::ctxt<'tcx>,
-                          lhs: Ty<'tcx>,
+fn is_builtin_binop<'tcx>(lhs: Ty<'tcx>,
                           rhs: Ty<'tcx>,
                           op: ast::BinOp)
                           -> bool
@@ -429,28 +428,28 @@ fn is_builtin_binop<'tcx>(cx: &ty::ctxt<'tcx>,
         BinOpCategory::Shift => {
             lhs.references_error() || rhs.references_error() ||
                 lhs.is_integral() && rhs.is_integral() ||
-                lhs.is_simd(cx) && rhs.is_simd(cx)
+                lhs.is_simd() && rhs.is_simd()
         }
 
         BinOpCategory::Math => {
             lhs.references_error() || rhs.references_error() ||
                 lhs.is_integral() && rhs.is_integral() ||
                 lhs.is_floating_point() && rhs.is_floating_point() ||
-                lhs.is_simd(cx) && rhs.is_simd(cx)
+                lhs.is_simd() && rhs.is_simd()
         }
 
         BinOpCategory::Bitwise => {
             lhs.references_error() || rhs.references_error() ||
                 lhs.is_integral() && rhs.is_integral() ||
                 lhs.is_floating_point() && rhs.is_floating_point() ||
-                lhs.is_simd(cx) && rhs.is_simd(cx) ||
+                lhs.is_simd() && rhs.is_simd() ||
                 lhs.is_bool() && rhs.is_bool()
         }
 
         BinOpCategory::Comparison => {
             lhs.references_error() || rhs.references_error() ||
                 lhs.is_scalar() && rhs.is_scalar() ||
-                lhs.is_simd(cx) && rhs.is_simd(cx)
+                lhs.is_simd() && rhs.is_simd()
         }
     }
 }