PR fortran/30611

	* trans-intrinsic.c (gfc_conv_intrinsic_repeat): Evaluate
	arguments only once. Generate check that NCOPIES argument is not
	negative.

	* intrinsics/string_intrinsics.c (string_repeat): Don't check
	if ncopies is negative.

	* gcc/testsuite/gfortran.dg/repeat_1.f90: New test.

From-SVN: r121581