rs6000.c (rs6000_gimple_fold_builtin): Add handling for early expansion of vec_min and vec_max builtins.

[gcc]

2017-06-02  Will Schmidt  <will_schmidt@vnet.ibm.com>
	* config/rs6000/rs6000.c (rs6000_gimple_fold_builtin): Add handling
	for early expansion of vec_min and vec_max builtins.
	(builtin_function_type): Add min/max unsigned variants to those
	identified as having unsigned arguments.

[gcc/testsuite]

2017-06-02  Will Schmidt  <will_schmidt@vnet.ibm.com>

	*  testsuite/gcc.target/powerpc/fold-vec-minmax-char.c: New.
	*  testsuite/gcc.target/powerpc/fold-vec-minmax-floatdouble.c: New.
	*  testsuite/gcc.target/powerpc/fold-vec-minmax-int.c: New.
	*  testsuite/gcc.target/powerpc/fold-vec-minmax-longlong.c: New.
	*  testsuite/gcc.target/powerpc/fold-vec-minmax-short.c: New.

From-SVN: r248834