diff --git a/filetests/isa/riscv/legalize-abi.cton b/filetests/isa/riscv/legalize-abi.cton
index 2e7da079bf..06d68768bd 100644
--- a/filetests/isa/riscv/legalize-abi.cton
+++ b/filetests/isa/riscv/legalize-abi.cton
@@ -34,9 +34,8 @@ ebb0:
     ; check: $ebb0:
     ; nextln: $(v1l=$V), $(v1h=$V) = call $fn1()
     ; check: $(v1new=$V) = iconcat $v1l, $v1h
-    ; check: $v1 = copy $v1new
     jump ebb1(v1)
-    ; The v1 copy gets resolved by split::simplify_branch_arguments().
+    ; The v1 alias gets resolved by split::simplify_branch_arguments().
     ; check: jump $ebb1($v1new)
 
 ebb1(v10: i64):
@@ -77,9 +76,8 @@ ebb0:
     ; check: $ebb0:
     ; nextln: $(rv=$V) = call $fn1()
     ; check: $(v1new=$V) = ireduce.i8 $rv
-    ; check: $v1 = copy $v1new
     jump ebb1(v1)
-    ; The v1 copy gets resolved by split::simplify_branch_arguments().
+    ; The v1 alias gets resolved by split::simplify_branch_arguments().
     ; check: jump $ebb1($v1new)
 
 ebb1(v10: i8):
diff --git a/lib/cretonne/src/ir/dfg.rs b/lib/cretonne/src/ir/dfg.rs
index 0b0ea7a8cc..359a6cd089 100644
--- a/lib/cretonne/src/ir/dfg.rs
+++ b/lib/cretonne/src/ir/dfg.rs
@@ -454,8 +454,14 @@ impl DataFlowGraph {
         *self.insts[inst].first_type_mut() = first_type.unwrap_or_default();
 
         // Include the first result in the results vector.
-        if first_type.is_some() {
-            self.results[inst].push(Value::new_direct(inst), &mut self.value_lists);
+        if let Some(ty) = first_type {
+            let v = self.make_value(ValueData::Inst {
+                                        ty: ty,
+                                        num: 0,
+                                        inst: inst,
+                                        next: head.into(),
+                                    });
+            self.results[inst].push(v, &mut self.value_lists);
         }
         self.results[inst]
             .as_mut_slice(&mut self.value_lists)
@@ -489,11 +495,10 @@ impl DataFlowGraph {
             return None;
         }
 
+        let first = self.results[inst].first(&mut self.value_lists).unwrap();
         let second = self.results[inst].get(1, &mut self.value_lists);
         self.results[inst].clear(&mut self.value_lists);
-        if !self.insts[inst].first_type().is_void() {
-            self.results[inst].push(Value::new_direct(inst), &mut self.value_lists);
-        }
+        self.results[inst].push(first, &mut self.value_lists);
         second
     }
 
@@ -649,21 +654,36 @@ impl DataFlowGraph {
     pub fn redefine_first_value(&mut self, pos: &mut Cursor) -> Inst {
         let orig = pos.current_inst()
             .expect("Cursor must point at an instruction");
+        let first_res = self.first_result(orig);
+        let first_type = self.value_type(first_res);
         let data = self[orig].clone();
-        // After cloning, any secondary values are attached to both copies. Don't do that, we only
-        // want them on the new clone.
-        let mut results = self.results[orig].take();
-        self.detach_secondary_results(orig);
+        let results = self.results[orig].take();
+        self.results[orig].push(first_res, &mut self.value_lists);
+
+
         let new = self.make_inst(data);
-        results.as_mut_slice(&mut self.value_lists)[0] = Value::new_direct(new);
-        self.results[new] = results;
+        let new_first = self.make_value(ValueData::Inst {
+                                            ty: first_type,
+                                            num: 0,
+                                            inst: new,
+                                            next: None.into(),
+                                        });
+        self.results[new].push(new_first, &mut self.value_lists);
+
+        for i in 1.. {
+            if let Some(v) = results.get(i, &self.value_lists) {
+                self.attach_result(new, v);
+            } else {
+                break;
+            }
+        }
+
         pos.insert_inst(new);
         // Replace the original instruction with a copy of the new value.
         // This is likely to be immediately overwritten by something else, but this way we avoid
         // leaving the DFG in a state with multiple references to secondary results and value
         // lists. It also means that this method doesn't change the semantics of the program.
-        let new_value = self.first_result(new);
-        self.replace(orig).copy(new_value);
+        self.replace(orig).copy(new_first);
         new
     }
 
@@ -898,7 +918,7 @@ mod tests {
         let inst = dfg.make_inst(idata);
         dfg.make_inst_results(inst, types::I32);
         assert_eq!(inst.to_string(), "inst0");
-        assert_eq!(dfg.display_inst(inst).to_string(), "v0 = iconst.i32");
+        assert_eq!(dfg.display_inst(inst).to_string(), "vx0 = iconst.i32");
 
         // Immutable reference resolution.
         {
diff --git a/lib/cretonne/src/legalizer/boundary.rs b/lib/cretonne/src/legalizer/boundary.rs
index f80b6574c4..272a19dfee 100644
--- a/lib/cretonne/src/legalizer/boundary.rs
+++ b/lib/cretonne/src/legalizer/boundary.rs
@@ -107,7 +107,7 @@ fn legalize_inst_results<ResType>(dfg: &mut DataFlowGraph,
                                   -> Inst
     where ResType: FnMut(&DataFlowGraph, usize) -> ArgumentType
 {
-    let mut call = pos.current_inst()
+    let call = pos.current_inst()
         .expect("Cursor must point to a call instruction");
 
     // We theoretically allow for call instructions that return a number of fixed results before
@@ -115,58 +115,26 @@ fn legalize_inst_results<ResType>(dfg: &mut DataFlowGraph,
     let fixed_results = dfg[call].opcode().constraints().fixed_results();
     assert_eq!(fixed_results, 0, "Fixed results  on calls not supported");
 
-    let mut next_res = dfg.detach_secondary_results(call);
-    // The currently last result on the call instruction.
-    let mut last_res = dfg.first_result(call);
+    let results = dfg.detach_results(call);
+    let mut next_res = 0;
     let mut abi_res = 0;
 
-    // The first result requires special handling.
-    let first_ty = dfg.value_type(last_res);
-    if first_ty != get_abi_type(dfg, abi_res).value_type {
-        // Move the call out of the way, so we can redefine the first result.
-        let copy = call;
-        call = dfg.redefine_first_value(pos);
-        last_res = dfg.first_result(call);
-        // Set up a closure that can attach new results to `call`.
-        let mut get_res = |dfg: &mut DataFlowGraph, ty| {
-            let abi_type = get_abi_type(dfg, abi_res);
-            if ty == abi_type.value_type {
-                // Don't append the first result - it's not detachable.
-                if fixed_results + abi_res == 0 {
-                    *dfg[call].first_type_mut() = ty;
-                    debug_assert_eq!(last_res, dfg.first_result(call));
-                } else {
-                    last_res = dfg.append_secondary_result(last_res, ty);
-                }
-                abi_res += 1;
-                Ok(last_res)
-            } else {
-                Err(abi_type)
-            }
-        };
-
-        let v = convert_from_abi(dfg, pos, first_ty, &mut get_res);
-        dfg.replace(copy).copy(v);
-    }
-
-    // Point immediately after the call and any instructions dealing with the first result.
+    // Point immediately after the call.
     pos.next_inst();
 
-    // Now do the secondary results.
-    while let Some(res) = next_res {
-        next_res = dfg.next_secondary_result(res);
+    while let Some(res) = results.get(next_res, &dfg.value_lists) {
+        next_res += 1;
 
         let res_type = dfg.value_type(res);
         if res_type == get_abi_type(dfg, abi_res).value_type {
             // No value translation is necessary, this result matches the ABI type.
-            dfg.attach_secondary_result(last_res, res);
-            last_res = res;
+            dfg.attach_result(call, res);
             abi_res += 1;
         } else {
             let mut get_res = |dfg: &mut DataFlowGraph, ty| {
                 let abi_type = get_abi_type(dfg, abi_res);
                 if ty == abi_type.value_type {
-                    last_res = dfg.append_secondary_result(last_res, ty);
+                    let last_res = dfg.append_result(call, ty);
                     abi_res += 1;
                     Ok(last_res)
                 } else {
@@ -199,13 +167,18 @@ fn convert_from_abi<GetArg>(dfg: &mut DataFlowGraph,
 {
     // Terminate the recursion when we get the desired type.
     let arg_type = match get_arg(dfg, ty) {
-        Ok(v) => return v,
+        Ok(v) => {
+            debug_assert_eq!(dfg.value_type(v), ty);
+            return v;
+        }
         Err(t) => t,
     };
 
     // Reconstruct how `ty` was legalized into the `arg_type` argument.
     let conversion = legalize_abi_value(ty, &arg_type);
 
+    dbg!("convert_from_abi({}): {:?}", ty, conversion);
+
     // The conversion describes value to ABI argument. We implement the reverse conversion here.
     match conversion {
         // Construct a `ty` by concatenating two ABI integers.
@@ -213,6 +186,11 @@ fn convert_from_abi<GetArg>(dfg: &mut DataFlowGraph,
             let abi_ty = ty.half_width().expect("Invalid type for conversion");
             let lo = convert_from_abi(dfg, pos, abi_ty, get_arg);
             let hi = convert_from_abi(dfg, pos, abi_ty, get_arg);
+            dbg!("intsplit {}: {}, {}: {}",
+                 lo,
+                 dfg.value_type(lo),
+                 hi,
+                 dfg.value_type(hi));
             dfg.ins(pos).iconcat(lo, hi)
         }
         // Construct a `ty` by concatenating two halves of a vector.
diff --git a/lib/reader/src/parser.rs b/lib/reader/src/parser.rs
index f948b1f586..a501d6aaa3 100644
--- a/lib/reader/src/parser.rs
+++ b/lib/reader/src/parser.rs
@@ -1750,12 +1750,12 @@ mod tests {
                 .unwrap();
         assert_eq!(func.name.to_string(), "qux");
         let v4 = details.map.lookup_str("v4").unwrap();
-        assert_eq!(v4.to_string(), "v0");
+        assert_eq!(v4.to_string(), "vx0");
         let vx3 = details.map.lookup_str("vx3").unwrap();
-        assert_eq!(vx3.to_string(), "vx0");
+        assert_eq!(vx3.to_string(), "vx2");
         let aliased_to = func.dfg
             .resolve_aliases(Value::table_with_number(0).unwrap());
-        assert_eq!(aliased_to.to_string(), "v0");
+        assert_eq!(aliased_to.to_string(), "vx0");
     }
 
     #[test]
diff --git a/lib/reader/src/sourcemap.rs b/lib/reader/src/sourcemap.rs
index cbea4b02a2..7f387ccee2 100644
--- a/lib/reader/src/sourcemap.rs
+++ b/lib/reader/src/sourcemap.rs
@@ -243,6 +243,6 @@ mod tests {
         assert_eq!(map.lookup_str("ebb0").unwrap().to_string(), "ebb0");
         assert_eq!(map.lookup_str("v4").unwrap().to_string(), "vx0");
         assert_eq!(map.lookup_str("vx7").unwrap().to_string(), "vx1");
-        assert_eq!(map.lookup_str("v10").unwrap().to_string(), "v0");
+        assert_eq!(map.lookup_str("v10").unwrap().to_string(), "vx2");
     }
 }