User Agent: Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/65.0.3325.181 Safari/537.36 Steps to reproduce: As GCC 8 will be released soon I'm attaching list of warnings seen. Note that -Wclass-memaccess should help to find issues where -flifetime-dse=2 causes removal of memset used to clear fileds of a class.

Thanks Martin! Here's some quick data on the file: egrep -e "\[-W(.+)\]" -o gcc8.txt | sort | uniq -c | sort -nr 1760 [-Wclass-memaccess] 1342 [-Wmultistatement-macros] 181 [-Wsign-compare] 82 [-Wunused-function] 74 [-Wint-in-bool-context] 62 [-Wsubobject-linkage] 51 [-Wimplicit-fallthrough=] 47 [-Wunused-but-set-variable] 44 [-Wmissing-attributes] 39 [-Wignored-qualifiers] 12 [-Wunknown-pragmas] 10 [-Wdiscarded-qualifiers] 10 [-Wdeprecated-declarations] 8 [-Wunused-value] 8 [-Wcpp] 7 [-Wunused-variable] 7 [-Wempty-body] 6 [-Wreorder] 6 [-Wmissing-prototypes] 5 [-Wimplicit-function-declaration] 3 [-Wunused-result] 3 [-Wmemset-elt-size] 2 [-Wsizeof-pointer-memaccess] 2 [-Wreturn-type] 1 [-Wunused-local-typedefs] 1 [-Wunused-const-variable=] 1 [-Wparentheses] 1 [-Wbool-operation] egrep -e "^gecko-dev/([^/]+)/" -o gcc8.txt | sed "s/gecko-dev\///" | sort | uniq -c | sort -nr 2888 obj-x86_64-pc-linux-gnu/ 338 gfx/ 226 media/ 132 js/ 86 security/ 65 nsprpub/ 30 dom/ 4 netwerk/ 3 xpcom/ 3 extensions/ 2 tools/ 2 third_party/ 2 modules/ 1 layout/ egrep -e "^gecko-dev/obj-x86_64-pc-linux-gnu/dist/([^ ]+)" -o gcc8.txt | sed "s/gecko-dev\///" | sort | uniq -c | sort -nr 1070 obj-x86_64-pc-linux-gnu/dist/include/mozilla/PodOperations.h:32:9: 864 obj-x86_64-pc-linux-gnu/dist/include/nsISupportsImpl.h:1016:5: 470 obj-x86_64-pc-linux-gnu/dist/include/nsISupportsImpl.h:1034:5: 462 obj-x86_64-pc-linux-gnu/dist/include/js/HashTable.h:1674:19: 5 obj-x86_64-pc-linux-gnu/dist/include/nsISupportsImpl.h:1048:5: 4 obj-x86_64-pc-linux-gnu/dist/include/mozilla/PodOperations.h:110:11: 3 obj-x86_64-pc-linux-gnu/dist/include/mozilla/PodOperations.h:46:11: 2 obj-x86_64-pc-linux-gnu/dist/include/nss/blapit.h:200:54: 2 obj-x86_64-pc-linux-gnu/dist/include/nspr/prlog.h:167:23: 2 obj-x86_64-pc-linux-gnu/dist/include/mozilla/PodOperations.h:157:10: 2 obj-x86_64-pc-linux-gnu/dist/include/js/Utility.h:552:15: 1 obj-x86_64-pc-linux-gnu/dist/include/nspr/prtypes.h:195:34: 1 obj-x86_64-pc-linux-gnu/dist/include/nspr/prtypes.h:195:29:

Please correct if this isn't the right component. Thanks.

Not really actionable, marking it duplicate of the meta bug