Hello world, here's the patch that was discussed.

Regression-tested. OK for trunk?

Since this appeared only in gcc13, I see no need for a backport.
I will also document this in the changes file.

Best regards

	Thomas

Set -frapv if -std=legacy is set.

Fortran legacy codes sometimes contain linear congruential
seudorandom number generators.  These generators implicitly depend
on wrapping behavior on integer overflow, which is illegal Fortran,
but the best they could to at the time.

A gcc13 change exposed this in rnflow, part of the Polyhedron
benchmark, with -O3.  Rather than "regress" on such code, this patch
enables -fwrapv if -std=legacy is enabled.  This allows the benchmark
to run successfully, and presumably lots of other code as well.

gcc/fortran/ChangeLog:

	PR fortran/109075
	* options.cc (gfc_handle_option):  If -std=legacy is set,
	also set -frwapv.
	* invoke.texi: Document the change.