re PR target/57744 (Power8 support has problems with quad word atomic instructions)

re PR target/57744 (Power8 support has problems with quad word atomic instructions)

[gcc]
2013-06-28  Michael Meissner  <meissner@linux.vnet.ibm.com>

	PR target/57744
	* config/rs6000/rs6000.h (MODES_TIEABLE_P): Do not allow PTImode
	to tie with any other modes.  Eliminate Altivec vector mode tests,
	since these are a subset of ALTIVEC or VSX vector modes.  Simplify
	code, to return 0 if testing MODE2 for a condition, if we've
	already tested MODE1 for the same condition.

[gcc/testsuite]
2013-06-28  Michael Meissner  <meissner@linux.vnet.ibm.com>

	PR target/57744
	* gcc.target/powerpc/pr57744.c: New test to make sure lqarx and
	stqcx. get even registers.

From-SVN: r200538