Merge pull request #2278 from akirilov-arm/load_splat

Introduce the Cranelift IR instruction `LoadSplat`

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

@@ -1892,3 +1892,31 @@ fn expand_tls_value(
         unreachable!();
     }
 }
+
+fn expand_load_splat(
+    inst: ir::Inst,
+    func: &mut ir::Function,
+    _cfg: &mut ControlFlowGraph,
+    _isa: &dyn TargetIsa,
+) {
+    let mut pos = FuncCursor::new(func).at_inst(inst);
+
+    pos.use_srcloc(inst);
+
+    let (ptr, offset, flags) = match pos.func.dfg[inst] {
+        ir::InstructionData::Load {
+            opcode: ir::Opcode::LoadSplat,
+            arg,
+            offset,
+            flags,
+        } => (arg, offset, flags),
+        _ => panic!(
+            "Expected load_splat: {}",
+            pos.func.dfg.display_inst(inst, None)
+        ),
+    };
+    let ty = pos.func.dfg.ctrl_typevar(inst);
+    let load = pos.ins().load(ty.lane_type(), flags, ptr, offset);
+
+    pos.func.dfg.replace(inst).splat(ty, load);
+}