Stop tracking if instruction formats have multiple results.

All instruction formats can represent multiple results now, so a few
redundant formats can be removed: UnarySplit and BinaryOverflow.

lib/cretonne/src/ir/instructions.rs

@@ -105,14 +105,12 @@ pub enum InstructionData {
     UnaryImm { opcode: Opcode, imm: Imm64 },
     UnaryIeee32 { opcode: Opcode, imm: Ieee32 },
     UnaryIeee64 { opcode: Opcode, imm: Ieee64 },
-    UnarySplit { opcode: Opcode, arg: Value },
     Binary { opcode: Opcode, args: [Value; 2] },
     BinaryImm {
         opcode: Opcode,
         arg: Value,
         imm: Imm64,
     },
-    BinaryOverflow { opcode: Opcode, args: [Value; 2] },
     Ternary { opcode: Opcode, args: [Value; 3] },
     MultiAry { opcode: Opcode, args: ValueList },
     InsertLane {

lib/cretonne/src/verifier.rs

@@ -255,10 +255,8 @@ impl<'a> Verifier<'a> {
             &UnaryImm { .. } |
             &UnaryIeee32 { .. } |
             &UnaryIeee64 { .. } |
-            &UnarySplit { .. } |
             &Binary { .. } |
             &BinaryImm { .. } |
-            &BinaryOverflow { .. } |
             &Ternary { .. } |
             &InsertLane { .. } |
             &ExtractLane { .. } |

lib/cretonne/src/write.rs

@@ -245,10 +245,8 @@ pub fn write_operands(w: &mut Write, dfg: &DataFlowGraph, inst: Inst) -> Result
         UnaryImm { imm, .. } => write!(w, " {}", imm),
         UnaryIeee32 { imm, .. } => write!(w, " {}", imm),
         UnaryIeee64 { imm, .. } => write!(w, " {}", imm),
-        UnarySplit { arg, .. } => write!(w, " {}", arg),
         Binary { args, .. } => write!(w, " {}, {}", args[0], args[1]),
         BinaryImm { arg, imm, .. } => write!(w, " {}, {}", arg, imm),
-        BinaryOverflow { args, .. } => write!(w, " {}, {}", args[0], args[1]),
         Ternary { args, .. } => write!(w, " {}, {}, {}", args[0], args[1], args[2]),
         MultiAry { ref args, .. } => {
             if args.is_empty() {