diff --git a/src/librustc_codegen_ssa/mir/block.rs b/src/librustc_codegen_ssa/mir/block.rs
index 4774f8fe5a3..494355efeaa 100644
--- a/src/librustc_codegen_ssa/mir/block.rs
+++ b/src/librustc_codegen_ssa/mir/block.rs
@@ -657,7 +657,7 @@ impl<'a, 'tcx: 'a, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
                             span_bug!(span, "shuffle indices must be constant");
                         }
                         mir::Operand::Constant(ref constant) => {
-                            let c = self.eval_mir_constant(&bx, constant);
+                            let c = self.eval_mir_constant(constant);
                             let (llval, ty) = self.simd_shuffle_indices(
                                 &bx,
                                 constant.span,
diff --git a/src/librustc_codegen_ssa/mir/constant.rs b/src/librustc_codegen_ssa/mir/constant.rs
index a1d44b228a5..3f8dc420cf4 100644
--- a/src/librustc_codegen_ssa/mir/constant.rs
+++ b/src/librustc_codegen_ssa/mir/constant.rs
@@ -3,7 +3,7 @@ use rustc_mir::const_eval::const_field;
 use rustc::mir;
 use rustc_data_structures::indexed_vec::Idx;
 use rustc::ty::{self, Ty};
-use rustc::ty::layout;
+use rustc::ty::layout::{self, HasTyCtxt};
 use syntax::source_map::Span;
 use crate::traits::*;
 
@@ -12,20 +12,19 @@ use super::FunctionCx;
 impl<'a, 'tcx: 'a, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
     pub fn eval_mir_constant(
         &mut self,
-        bx: &Bx,
         constant: &mir::Constant<'tcx>,
     ) -> Result<ty::Const<'tcx>, ErrorHandled> {
         match constant.literal.val {
             mir::interpret::ConstValue::Unevaluated(def_id, ref substs) => {
                 let substs = self.monomorphize(substs);
                 let instance = ty::Instance::resolve(
-                    bx.tcx(), ty::ParamEnv::reveal_all(), def_id, substs,
+                    self.cx.tcx(), ty::ParamEnv::reveal_all(), def_id, substs,
                 ).unwrap();
                 let cid = mir::interpret::GlobalId {
                     instance,
                     promoted: None,
                 };
-                bx.tcx().const_eval(ty::ParamEnv::reveal_all().and(cid))
+                self.cx.tcx().const_eval(ty::ParamEnv::reveal_all().and(cid))
             },
             _ => Ok(*self.monomorphize(&constant.literal)),
         }
diff --git a/src/librustc_codegen_ssa/mir/operand.rs b/src/librustc_codegen_ssa/mir/operand.rs
index e17a6e7b03f..289129e8e62 100644
--- a/src/librustc_codegen_ssa/mir/operand.rs
+++ b/src/librustc_codegen_ssa/mir/operand.rs
@@ -460,7 +460,7 @@ impl<'a, 'tcx: 'a, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
 
             mir::Operand::Constant(ref constant) => {
                 let ty = self.monomorphize(&constant.ty);
-                self.eval_mir_constant(bx, constant)
+                self.eval_mir_constant(constant)
                     .and_then(|c| OperandRef::from_const(bx, c))
                     .unwrap_or_else(|err| {
                         match err {