Improved SSA and added unused value checks

src/ssa/Syscall.go

@@ -0,0 +1,27 @@
+package ssa
+
+import "fmt"
+
+type Syscall struct {
+	Arguments
+	Liveness
+	HasToken
+}
+
+func (a *Syscall) Equals(v Value) bool {
+	b, sameType := v.(*Syscall)
+
+	if !sameType {
+		return false
+	}
+
+	return a.Arguments.Equals(b.Arguments)
+}
+
+func (v *Syscall) IsConst() bool {
+	return false
+}
+
+func (v *Syscall) String() string {
+	return fmt.Sprintf("syscall%v", v.Args)
+}