g77 rejects things other compilers accept, like INTRINSIC SQRT,SQRT. As time permits in the future, some of these things that are easy for humans to read and write and unlikely to be intended to mean something else will be accepted by g77 (though -fpedantic should trigger warnings about such non-standard constructs).
Until g77 no longer gratuitously rejects sensible code, you might as well fix your code to be more standard-conforming and portable.
The kind of case that is important to except from the recommendation to change your code is one where following good coding rules would force you to write non-standard code that nevertheless has a clear meaning.
For example, when writing an INCLUDE file that
defines a common block, it might be appropriate to
include a SAVE statement for the common block
(such as SAVE /CBLOCK/), so that variables
defined in the common block retain their values even
when all procedures declaring the common block become
inactive (return to their callers).
However, putting SAVE statements in an INCLUDE
file would prevent otherwise standard-conforming code
from also specifying the SAVE statement, by itself,
to indicate that all local variables and arrays are to
have the SAVE attribute.
For this reason, g77 already has been changed to allow this combination, because although the general problem of gratuitously rejecting unambiguous and “safe” constructs still exists in g77, this particular construct was deemed useful enough that it was worth fixing g77 for just this case.
So, while there is no need to change your code to avoid using this particular construct, there might be other, equally appropriate but non-standard constructs, that you shouldn't have to stop using just because g77 (or any other compiler) gratuitously rejects it.
Until the general problem is solved, if you have any such construct you believe is worthwhile using (e.g. not just an arbitrary, redundant specification of an attribute), please submit a bug report with an explanation, so we can consider fixing g77 just for cases like yours.