diff --git a/compute-coverage.sh b/compute-coverage.sh
index bd1e12a0d..d86f3fc5a 100755
--- a/compute-coverage.sh
+++ b/compute-coverage.sh
@@ -14,13 +14,41 @@ set -Eeuxo pipefail
 #    directory containing this script.
 
 # Combine .tix files
+# Avoid tripping on an existing all.tix from a prior run
 SUM_TIX="all.tix"
-hpc sum --output=$SUM_TIX --union --exclude=Main --exclude=GitRev $(find . -name "*.tix")
+hpc sum --output=$SUM_TIX --union --exclude=Main --exclude=GitRev \
+        $(find . ! -path ./all.tix -name "*.tix" -print)
 
-# Generate report
-HPC_ROOT=$(find dist-newstyle -name "hpc")
+# Find the HPC dir, and don't trip on old versions after a version bump.
+# See saw-script #2114.
+#
+# There is no direct way to do this. Instead, fetch the name of the
+# SAW executable. This gives us a path into the build directory for
+# the current version:
+#    dist-newstyle/build/$TARGET/ghc-$GHC/saw-script-$VERSION/build/saw/saw
+#
+# where we don't want to have to try to figure out $TARGET, $GHC, or $VERSION.
+#
+# The hpc dir we want lives under the saw-script-$VERSION dir, but can be in
+# different places with different versions of the tooling. So start there and
+# then use find.
+#
+# -v0 (verbosity 0) prevents cabal from accidentally including extraneous
+# data (see saw-script #2103)
+SAW=$(cabal list-bin -v0 exe:saw)
+SAWSCRIPT=$(echo "$SAW" | sed 's,/build/saw/saw$,,')
+HPC_ROOT=$(find "$SAWSCRIPT" -name "hpc" -print)
+
+# Check if it actually exists, in case it doesn't, and bail with an error
+# message instead of generating hpc's usage message.
+if ! [ -d "$HPC_ROOT" ]; then
+    echo "$0: no HPC dir found" 1>&2
+    exit 1
+fi
+
+# Now generate the report
 HPC_ARGS=""
-for dir in ${HPC_ROOT}/vanilla/mix/*; do
+for dir in "$HPC_ROOT"/vanilla/mix/*; do
   HPC_ARGS="${HPC_ARGS} --hpcdir=${dir}"
 done
 hpc markup --destdir=hpc-html ${HPC_ARGS} ${SUM_TIX}