Replace InsertLane format with TernaryImm8

The InsertLane format has an ordering (`value().imm().value()`) and immediate name (`"lane"`) that make it awkward to use for other instructions. This changes the ordering (`value().value().imm()`) and uses the default name (`"imm"`) throughout the codebase.

cranelift/codegen/src/isa/x86/enc_tables.rs

@@ -1251,10 +1251,10 @@ fn convert_insertlane(
     let mut pos = FuncCursor::new(func).at_inst(inst);
     pos.use_srcloc(inst);
 
-    if let ir::InstructionData::InsertLane {
+    if let ir::InstructionData::TernaryImm8 {
         opcode: ir::Opcode::Insertlane,
         args: [vector, replacement],
-        lane,
+        imm: lane,
     } = pos.func.dfg[inst]
     {
         let value_type = pos.func.dfg.value_type(vector);
@@ -1269,7 +1269,7 @@ fn convert_insertlane(
                     pos.func
                         .dfg
                         .replace(inst)
-                        .x86_insertps(vector, immediate, replacement)
+                        .x86_insertps(vector, replacement, immediate)
                 }
                 F64X2 => {
                     let replacement_as_vector = pos.ins().raw_bitcast(F64X2, replacement); // only necessary due to SSA types
@@ -1297,7 +1297,7 @@ fn convert_insertlane(
             pos.func
                 .dfg
                 .replace(inst)
-                .x86_pinsr(vector, lane, replacement);
+                .x86_pinsr(vector, replacement, lane);
         }
     }
 }
@@ -1340,7 +1340,7 @@ fn expand_dword_to_xmm<'f>(
     if arg_type == I64 {
         let (arg_lo, arg_hi) = pos.ins().isplit(arg);
         let arg = pos.ins().scalar_to_vector(I32X4, arg_lo);
-        let arg = pos.ins().insertlane(arg, 1, arg_hi);
+        let arg = pos.ins().insertlane(arg, arg_hi, 1);
         let arg = pos.ins().raw_bitcast(I64X2, arg);
         arg
     } else {

cranelift/codegen/src/verifier/mod.rs

@@ -758,7 +758,7 @@ impl<'a> Verifier<'a> {
             | Binary { .. }
             | BinaryImm { .. }
             | Ternary { .. }
-            | InsertLane { .. }
+            | TernaryImm8 { .. }
             | ExtractLane { .. }
             | Shuffle { .. }
             | IntCompare { .. }
@@ -1918,14 +1918,14 @@ impl<'a> Verifier<'a> {
                 arg,
                 ..
             }
-            | ir::InstructionData::InsertLane {
+            | ir::InstructionData::TernaryImm8 {
                 opcode: ir::instructions::Opcode::Insertlane,
-                lane,
+                imm: lane,
                 args: [arg, _],
                 ..
             } => {
                 // We must be specific about the opcodes above because other instructions are using
-                // the ExtractLane/InsertLane formats.
+                // the same formats.
                 let ty = self.func.dfg.value_type(arg);
                 if u16::from(lane) >= ty.lane_count() {
                     errors.fatal((

cranelift/codegen/src/write.rs

@@ -518,7 +518,7 @@ pub fn write_operands(
             }
         }
         NullAry { .. } => write!(w, " "),
-        InsertLane { lane, args, .. } => write!(w, " {}, {}, {}", args[0], lane, args[1]),
+        TernaryImm8 { imm, args, .. } => write!(w, " {}, {}, {}", args[0], args[1], imm),
         ExtractLane { lane, arg, .. } => write!(w, " {}, {}", arg, lane),
         Shuffle { mask, args, .. } => {
             let data = dfg.immediates.get(mask).expect(