rs6000: Using pli(paddi) and rotate to build 64bit constants

rs6000: Using pli(paddi) and rotate to build 64bit constants

Hi,

Test cases are updated/added, and code is refined as the comments in the
review for previous version:
https://gcc.gnu.org/pipermail/gcc-patches/2022-September/600768.html

As mentioned in PR106550, since pli could support 34bits immediate, we could
use less instructions(3insn would be ok) to build 64bits constant with pli.

For example, for constant 0x020805006106003, we could generate it with:
asm code1:
pli 9,101736451 (0x6106003)
sldi 9,9,32
paddi 9,9, 2130000 (0x0208050)

or asm code2:
pli 10, 2130000
pli 9, 101736451
rldimi 9, 10, 32, 0

The asm code2 would be better.
This patch generates the asm code2 in split1 pass, this patch also supports
to generate asm code1 when splitter is only after RA.

This patch pass boostrap and regtest on ppc64. P10 testing is running.
Thanks for any comments!

BR,
Jeff(Jiufu)

	PR target/106550

gcc/ChangeLog:

	* config/rs6000/rs6000.cc (rs6000_emit_set_long_const): Use pli.

gcc/testsuite/ChangeLog:

	* gcc.target/powerpc/pr106550.c: New test.
	* gcc.target/powerpc/pr106550_1.c: New test.