Is there really only one symbol_ref object referring to each symbolic label?

[Zack Weinberg]

Geoff Keating <geoffk@geoffk.org> writes:

> Yup.  They should look like
>
> gen_rtx_SYMBOL_REF (xxx, ggc_strdup ("yyy"))
>
> You don't want to make the ggc_strdup be part of gen_rtx_* because 99%
> of the time it's not necessary and the extra hash-table lookup is
> slow...

ggc_strdup is a macro wrapper for ggc_alloc_string, and
ggc_alloc_string does NOT guarantee the uniqueness of the strings it
returns.  (However, I consider this a bug in ggc_alloc_string, not in
its callers.  At one time ggc_alloc_string did uniquize strings - I
don't know when that got changed or why.)

zw