Enable side-effect free check in CI

Author: sipa

.cirrus.yml

@@ -17,6 +17,7 @@ env:
   BENCH: yes
   ITERS: 2
   MAKEFLAGS: -j2
+  CHECK_SIDE_EFFECT_FREE: yes
 
 cat_logs_snippet: &CAT_LOGS
   always:
@@ -64,7 +65,7 @@ task:
     - env: {BIGNUM: no,       STATICPRECOMPUTATION: no}
     - env: {BUILD: distcheck, WITH_VALGRIND: no, CTIMETEST: no, BENCH: no}
     - env: {CPPFLAGS: -DDETERMINISTIC}
-    - env: {CFLAGS: -O0, CTIMETEST: no}
+    - env: {CFLAGS: -O0, CTIMETEST: no, CHECK_SIDE_EFFECT_FREE: no}
     - env:
         CFLAGS:  "-fsanitize=undefined -fno-omit-frame-pointer"
         LDFLAGS: "-fsanitize=undefined -fno-omit-frame-pointer"
@@ -93,6 +94,7 @@ task:
         CC: gcc
     - env:
         CC: clang
+        CHECK_SIDE_EFFECT_FREE: auto
   << : *MERGE_BASE
   test_script:
     - ./ci/cirrus.sh
@@ -115,6 +117,7 @@ task:
         CC: i686-linux-gnu-gcc
     - env:
         CC: clang --target=i686-pc-linux-gnu -isystem /usr/i686-linux-gnu/include
+        CHECK_SIDE_EFFECT_FREE: auto
   matrix:
     - env:
         BIGNUM: gmp
@@ -141,6 +144,7 @@ task:
         CC: gcc-9
     - env:
         CC: clang
+        CHECK_SIDE_EFFECT_FREE: auto
   # Update Command Line Tools
   # Uncomment this if the Command Line Tools on the CirrusCI macOS image are too old to brew valgrind.
   # See https://apple.stackexchange.com/a/195963 for the implementation.

ci/cirrus.sh

@@ -19,6 +19,7 @@ valgrind --version || true
     --enable-module-ecdh="$ECDH" --enable-module-recovery="$RECOVERY" \
     --enable-module-schnorrsig="$SCHNORRSIG" \
     --with-valgrind="$WITH_VALGRIND" \
+    --enable-side-effect-free-check="$CHECK_SIDE_EFFECT_FREE" \
     --host="$HOST" $EXTRAFLAGS
 
 # We have set "-j<n>" in MAKEFLAGS.