diff --git a/lib/cretonne/src/ir/dfg.rs b/lib/cretonne/src/ir/dfg.rs
index 25859535bc..dbb643e7f3 100644
--- a/lib/cretonne/src/ir/dfg.rs
+++ b/lib/cretonne/src/ir/dfg.rs
@@ -4,7 +4,7 @@ use entity::{PrimaryMap, EntityMap};
 use isa::TargetIsa;
 use ir::builder::{InsertBuilder, ReplaceBuilder};
 use ir::extfunc::ExtFuncData;
-use ir::instructions::{Opcode, InstructionData, CallInfo};
+use ir::instructions::{InstructionData, CallInfo};
 use ir::layout::{Cursor, LayoutCursorInserter};
 use ir::types;
 use ir::{Ebb, Inst, Value, Type, SigRef, Signature, FuncRef, ValueList, ValueListPool};
@@ -211,33 +211,6 @@ impl DataFlowGraph {
         resolve_aliases(&self.values, value)
     }
 
-    /// Resolve value copies.
-    ///
-    /// Find the original definition of a value, looking through value aliases as well as
-    /// copy/spill/fill instructions.
-    pub fn resolve_copies(&self, value: Value) -> Value {
-        let mut v = value;
-
-        for _ in 0..self.insts.len() {
-            v = self.resolve_aliases(v);
-            v = match self.value_def(v) {
-                ValueDef::Res(inst, 0) => {
-                    match self[inst] {
-                        InstructionData::Unary { opcode, arg, .. } => {
-                            match opcode {
-                                Opcode::Copy | Opcode::Spill | Opcode::Fill => arg,
-                                _ => return v,
-                            }
-                        }
-                        _ => return v,
-                    }
-                }
-                _ => return v,
-            };
-        }
-        panic!("Copy loop detected for {}", value);
-    }
-
     /// Resolve all aliases among inst's arguments.
     ///
     /// For each argument of inst which is defined by an alias, replace the
@@ -1090,7 +1063,5 @@ mod tests {
         let c3 = pos.ins().copy(c);
         // This does not see through copies.
         assert_eq!(pos.func.dfg.resolve_aliases(c3), c3);
-        // But this goes through both copies and aliases.
-        assert_eq!(pos.func.dfg.resolve_copies(c3), c2);
     }
 }
diff --git a/lib/cretonne/src/legalizer/split.rs b/lib/cretonne/src/legalizer/split.rs
index 62e5391474..96e1b03145 100644
--- a/lib/cretonne/src/legalizer/split.rs
+++ b/lib/cretonne/src/legalizer/split.rs
@@ -190,7 +190,7 @@ fn split_value(
     concat: Opcode,
     repairs: &mut Vec<Repair>,
 ) -> (Value, Value) {
-    let value = pos.func.dfg.resolve_copies(value);
+    let value = pos.func.dfg.resolve_aliases(value);
     let mut reuse = None;
 
     match pos.func.dfg.value_def(value) {
@@ -293,7 +293,7 @@ fn add_repair(
 ///
 /// This function resolves `v11` to `v1` and `v12` to `v2`.
 fn resolve_splits(dfg: &ir::DataFlowGraph, value: Value) -> Value {
-    let value = dfg.resolve_copies(value);
+    let value = dfg.resolve_aliases(value);
 
     // Deconstruct a split instruction.
     let split_res;