Dear all,

we are accepting loop annotations IVDEP, UNROLL n, VECTOR, and NOVECTOR
for ordinary do loops, but ICE when such an annotation is specified
before a DO CONCURRENT loop.

Since at least the Intel compilers recognize some of the annotations
also for DO CONCURRENT, it seems natural to extend gfortran instead
of rejecting or ignoring the attributes.

The attached patch handles the annotations as needed for the control
structures of FORALL/DO CONCURRENT.

Regarding the UNROLL directive, I don't have good references, so
feedback is welcome.  The current patch applies UNROLL only to
the first loop control variable (for the case of loop nests),
which translates into the innermost loop in gcc's representation.

Regtested on x86_64-pc-linux-gnu.

OK for mainline?

Comments?

Thanks,
Harald