diff --git a/.cirrus.yml b/.cirrus.yml
index cec5ad8fffb4a..a9ccffc92e3ee 100644
--- a/.cirrus.yml
+++ b/.cirrus.yml
@@ -80,6 +80,7 @@ task:
     - env: {BUILD: distcheck, WITH_VALGRIND: no, CTIMETESTS: no, BENCH: no}
     - env: {CPPFLAGS: -DDETERMINISTIC}
     - env: {CFLAGS: -O0, CTIMETESTS: no}
+    - env: {CFLAGS: -O1, RECOVERY: yes, ECDH: yes, SCHNORRSIG: yes, ELLSWIFT: yes}
     - env: { ECMULTGENPRECISION: 2, ECMULTWINDOW: 2 }
     - env: { ECMULTGENPRECISION: 8, ECMULTWINDOW: 4 }
   matrix:
diff --git a/src/ecmult_impl.h b/src/ecmult_impl.h
index f4624677d7fe0..6d14c7ac4be7c 100644
--- a/src/ecmult_impl.h
+++ b/src/ecmult_impl.h
@@ -288,7 +288,9 @@ static void secp256k1_ecmult_strauss_wnaf(const struct secp256k1_strauss_state *
     }
 
     /* Bring them to the same Z denominator. */
-    secp256k1_ge_table_set_globalz(ECMULT_TABLE_SIZE(WINDOW_A) * no, state->pre_a, state->aux);
+    if (no) {
+        secp256k1_ge_table_set_globalz(ECMULT_TABLE_SIZE(WINDOW_A) * no, state->pre_a, state->aux);
+    }
 
     for (np = 0; np < no; ++np) {
         for (i = 0; i < ECMULT_TABLE_SIZE(WINDOW_A); i++) {