rs6000: Fix invalid splits when using Altivec style addresses [PR98959]

rs6000: Fix invalid splits when using Altivec style addresses [PR98959]

The rs6000_emit_le_vsx_* functions assume they are not passed an Altivec
style "& ~16" address.  However, some of our expanders and splitters do
not verify we do not have an Altivec style address before calling those
functions, leading to an ICE.  The solution here is to guard the expanders
and splitters to ensure we do not call them if we're given an Altivec style
address.

2021-03-08  Peter Bergner  <bergner@linux.ibm.com>

gcc/
	PR target/98959
	* config/rs6000/rs6000.c (rs6000_emit_le_vsx_permute): Add an assert
	to ensure we do not have an Altivec style address.
	* config/rs6000/vsx.md (*vsx_le_perm_load_<mode>): Disable if passed
	an Altivec style address.
	(*vsx_le_perm_store_<mode>): Likewise.
	(splitters after *vsx_le_perm_store_<mode>): Likewise.
	(vsx_load_<mode>): Disable special expander if passed an Altivec
	style address.
	(vsx_store_<mode>): Likewise.

gcc/testsuite/
	PR target/98959
	* gcc.target/powerpc/pr98959.c: New test.

(cherry picked from commit cb25dea3ef2c7768007bffc56f0e31e1c42b44e2)