[COMMITTED] PowerPC: Remove 64 bits instructions in PPC32 code

[Adhemerval Zanella]

On 26-05-2014 15:12, Segher Boessenkool wrote:
>> This patch replaces the insrdi by insrwi in powerpc32 assembly.  Although they
>> are not wrong, since all POWER chips supported in 32-bits are 64-bits and the chips
>> do not thrown an illegal exception when running these instructions, valgrind
>> fails accusing an invalid one.
> This code is CPU-specific; as you say, those CPUs can use rldimi just
> fine.  The reason the code uses rldimi instead of rlwimi is because
> it is faster (at least on power4, power5).  Fix valgrind instead?
>
>
> Segher
>
Well, using http://pastebin.com/CttashRQ on a POWER5 (1.9 GHz) I get:

> ./test 
rldimi: min: 7 | max: 9
rlwimi: min: 7 | max: 10

And by issuing 16 instruction per test function I get:

> ./test 
rldimi: min: 7 | max: 9
rlwimi: min: 7 | max: 13

Newer processor (POWER7) also shows the same behavior.  And the instructions
and not in hot path in the code (it is only called once), so I hardly consider
this a performance regression. 

Anyway, I would prefer to keep consistent and using only 32-bits in 32-bits 
assembly code to avoid such issues with external tools (valgrind is only an
example) and to allow possible future implementation in different chips that
do not implement the 64-bits instructions to use powerN code.