PR fortran/19239: Handle general vector subscripts

[Paul Brook]

> gcc/fortran/
> 	PR fortran/19239
> 	* Makefile.in (fortran/trans-expr.o): Depend on dependency.h.
> 	* dependency.h (gfc_ref_needs_temporary_p): Declare.
> 	* dependency.c (gfc_ref_needs_temporary_p): New function.
> 	(gfc_check_fncall_dependency): Use it instead of inlined check.
> 	By so doing, take advantage of the fact that character substrings
> 	within an array reference also need a temporary.
> 	* trans.h (GFC_SS_VECTOR): Adjust comment.
> 	* trans-array.c (gfc_free_ss): Remove GFC_SS_VECTOR case.
> 	(gfc_set_vector_loop_bounds): New function.
> 	(gfc_add_loop_ss_code): Call it after evaluating the subscripts of
> 	a GFC_SS_SECTION.  Deal with the GFC_SS_VECTOR case by evaluating
> 	the vector expression and caching its descriptor for use within
> 	the loop.
> 	(gfc_conv_array_index_ref, gfc_conv_vector_array_index): Delete.
> 	(gfc_conv_array_index_offset): Handle scalar, vector and range
> 	dimensions as separate cases of a switch statement.  In the vector
> 	case, use the loop variable to calculate a vector index and use the
> 	referenced element as the dimension's index.  Perform bounds checking
> 	on this final index.
> 	(gfc_conv_section_upper_bound): Return null for vector indexes.
> 	(gfc_conv_section_startstride): Give vector indexes a start value
> 	of 0 and a stride of 1.
> 	(gfc_conv_ss_startstride): Adjust for new GFC_SS_VECTOR representation.
> 	(gfc_conv_expr_descriptor): Expand comments.  Generalize the
> 	handling of the !want_pointer && !direct_byref case.  Use
> 	gfc_ref_needs_temporary_p to decide whether the variable case
> 	needs a temporary.
> 	(gfc_walk_variable_expr): Handle DIMEN_VECTOR by creating a
> 	GFC_SS_VECTOR index.
> 	* trans-expr.c: Include dependency.h.
> 	(gfc_trans_arrayfunc_assign): Fail if the target needs a temporary.

Ok.

Paul