message: opt script: skip -Oz -Os and O[1-3]
diff: set -e
  # IPO passes aren't supported ATM
  -PASSES="argpromotion deadargelim globalopt hotcoldsplit inline ipconstprop ipsccp mergefunc partial-inliner tbaa -Os -O2 -O3"
  +PASSES="argpromotion deadargelim globalopt hotcoldsplit inline ipconstprop ipsccp mergefunc partial-inliner tbaa -Os -Oz -O1 -O2 -O3"
  TV="-tv"
  for p in $PASSES; do
  