Re: [rs6000] Don't emit libcall notes around TLS address

[Richard Henderson <rth at redhat dot com>]

On Tue, Jun 14, 2005 at 12:16:58PM +0200, Steven Bosscher wrote:
> IIUC this be done with a const builtin to turn it into something like
> 
> int foo2 (void)
> {
>   int *t1 = builtin_get_tls_addr (a);
>   bar (*t1);
>   int *t2 = builtin_get_tls_addr (a);
>   bar (*t2);
>   int *t3 = builtin_get_tls_addr (a);
>   bar (*t3);
> }
> 
> which PRE would turn into this:
> 
> int foo2 (void)
> {
>   int *t1 = builtin_get_tls_addr (a);

Yes, this could be done.  Though, really, I'm not sure a builtin buys
us anything here over just treating the ADDR_EXPR specially.

> If so, would you have ideas for a similar trick for the local-dynamic
> case?

Well, you need to split the address into two parts, like it really is
in practice.  A builtin with no arguments for the base plus a DTP_EXPR
for the offset.  You'll want an EXPR not a builtin so that it can get
stuffed into TARGET_MEM_REF at some point.


r~