c.ctxt.Diag("constrained unpredictable behavior: %v", p)
			}
			o1 |= uint32(p.To.Offset&31) << 10
		} else {
			o1 |= 0x1F << 10
		}
		o1 |= uint32(p.To.Reg & 31)

	case 59: /* stxr/stlxr/stxp/stlxp */
		s := p.RegTo2
		n := p.To.Reg
		t := p.From.Reg
		if isSTLXRop(p.As) {
			if s == t || (s == n && n != REGSP) {
				c.ctxt.Diag("constrained unpredictable behavior: %v", p)
			}