GNU replacing obsolete assembly instructions in PowerPc architecture

[Florian Weimer]

* ilya german:

> I have a quastion regarding reading TBR registers on PPC p2020 e500v2 CPU.
>
> I wrote the following asm instructions to read the TBR:
>
> mftbu r5 /* Read upper Time Base */
> mftb r6 /* Read lower Time Base */
> mftbu r7 /* Read upper Time Base again */
>
> When I compiled (using GNU 4) and viewed the asm instruction I saw that
> *mftbu* and *mftb* were replaced with *mfspr* instruction.

How did you determine that it was replaced?