After making sure LDC and its runtime are up to date, use
./runtest tmp-sensible-name
to run tests for LDC.
Move into reference/ subfolder and add to svn if desired.

Use
./findregressions old-test-resultfile tmp-sensible-name
to find changes.

Recommended for comparing to DMD:
./findregressions reference/dmd-version ldc-something | grep -v "PASS -> XFAIL" | sort > tmp-new-regressions