diff --git a/.github/workflows/libcxx-run-benchmarks.yml b/.github/workflows/libcxx-run-benchmarks.yml
index 0379a0a1f857d..9e8f55859fc7a 100644
--- a/.github/workflows/libcxx-run-benchmarks.yml
+++ b/.github/workflows/libcxx-run-benchmarks.yml
@@ -64,17 +64,21 @@ jobs:
           path: repo # Avoid nuking the workspace, where we have the Python virtualenv
 
       - name: Run baseline
+        env:
+          BENCHMARKS: ${{ steps.vars.outputs.benchmarks }}
         run: |
           source .venv/bin/activate && cd repo
           python -m pip install -r libcxx/utils/requirements.txt
           baseline_commit=$(git merge-base ${{ steps.vars.outputs.pr_base }} ${{ steps.vars.outputs.pr_head }})
-          ./libcxx/utils/test-at-commit --commit ${baseline_commit} -B build/baseline -- -sv -j1 --param optimization=speed ${{ steps.vars.outputs.benchmarks }}
+          ./libcxx/utils/test-at-commit --commit ${baseline_commit} -B build/baseline -- -sv -j1 --param optimization=speed "$BENCHMARKS"
           ./libcxx/utils/consolidate-benchmarks build/baseline | tee baseline.lnt
 
       - name: Run candidate
+        env:
+          BENCHMARKS: ${{ steps.vars.outputs.benchmarks }}
         run: |
           source .venv/bin/activate && cd repo
-          ./libcxx/utils/test-at-commit --commit ${{ steps.vars.outputs.pr_head }} -B build/candidate -- -sv -j1 --param optimization=speed ${{ steps.vars.outputs.benchmarks }}
+          ./libcxx/utils/test-at-commit --commit ${{ steps.vars.outputs.pr_head }} -B build/candidate -- -sv -j1 --param optimization=speed "$BENCHMARKS"
           ./libcxx/utils/consolidate-benchmarks build/candidate | tee candidate.lnt
 
       - name: Compare baseline and candidate runs