On 17/04/20 14:25, Uros Bizjak wrote: > I was going to say that it is documented in [1] under x86 family > section, but indeed, there is no description of "l" constraint. It is > internal to the compiler. :( Yes, I looked there. It's worth documenting it in GCC, I think. Paolo > (define_register_constraint "l" "INDEX_REGS" > "@internal Any register that can be used as the index in a base+index > memory access: that is, any general register except the stack pointer.")