-useless-if-before-free -l $(lid -knone free) | xargs -0 \
- perl -0x3b -pi -e \
- 's/\bif\s*\(\s*(\S+?)(?:\s*!=\s*NULL)?\s*\)\s+(free\s*\((?:\s*\([^)]+\))?\s*\1\s*\))/$2/s'
+free=xfree
+git grep -l -z "$free *(" \
+ | xargs -0 useless-if-before-free -l --name="$free" \
+ | xargs -0 perl -0x3b -pi -e \
+ 's/\bif\s*\(\s*(\S+?)(?:\s*!=\s*(?:0|NULL))?\s*\)\s+('"$free"'\s*\((?:\s*\([^)]+\))?\s*\1\s*\))/$2/s'