re PR fortran/45159 (Unnecessary temporaries)

re PR fortran/45159 (Unnecessary temporaries)

2013-03-28  Thomas Koenig  <tkoenig@gcc.gnu.org>

	PR fortran/45159
	* gfortran.h (gfc_dep_difference):  Add prototype.
	* dependency.c (discard_nops):  New function.
	(gfc_dep_difference):  New function.
	(check_section_vs_section):  Use gfc_dep_difference
	to calculate the difference of starting indices.
	* trans-expr.c (gfc_conv_substring):  Use
	gfc_dep_difference to calculate the length of
	substrings where possible.

2013-03-28  Thomas Koenig  <tkoenig@gcc.gnu.org>

	PR fortran/45159
	* gfortran.dg/string_length_2.f90:  New test.
	* gfortran.dg/dependency_41.f90:  New test.

From-SVN: r197217