trans-expr.c (is_zero_initializer_p): Determine whether a given constant expression...

trans-expr.c (is_zero_initializer_p): Determine whether a given constant expression is a zero initializer.

	* trans-expr.c (is_zero_initializer_p): Determine whether a given
	constant expression is a zero initializer.
	(gfc_trans_zero_assign): New function to attempt to optimize
	"a(:) = 0.0" as a call to __builtin_memset (a, 0, sizeof(a));
	(gfc_trans_assignment): Special case array assignments to a
	zero initializer constant, using gfc_trans_zero_assign.

	* gfortran.dg/array_memset_1.f90: New test case.

From-SVN: r120078