rs6000: Fix PTImode handling in power8 swap optimization pass [PR116415]

rs6000: Fix PTImode handling in power8 swap optimization pass [PR116415]

Our power8 swap optimization pass has some special handling for optimizing
swaps of TImode variables.  The test case reported in bugzilla uses a call
to  __atomic_compare_exchange, which introduces a variable of PTImode and
that does not get the same treatment as TImode leading to wrong code
generation.  The simple fix is to treat PTImode identically to TImode.

2024-08-23  Peter Bergner  <bergner@linux.ibm.com>

gcc/
	PR target/116415
	* config/rs6000/rs6000.h (TI_OR_PTI_MODE): New define.
	* config/rs6000/rs6000-p8swap.cc (rs6000_analyze_swaps): Use it to
	handle PTImode identically to TImode.

gcc/testsuite/
	PR target/116415
	* gcc.target/powerpc/pr116415.c: New test.

(cherry picked from commit 6e68c3df1540c5bafbb47343698bf4e270333fdb)