Hello, I noticed that we currently set flags for gcc to disable warnings.
See https://hg.openjdk.java.net/jdk/jdk/file/896e80158d35/make/hotspot/lib/CompileJvm.gmk DISABLED_WARNINGS_gcc := extra parentheses comment unknown-pragmas address \ delete-non-virtual-dtor char-subscripts array-bounds int-in-bool-context \ ignored-qualifiers missing-field-initializers implicit-fallthrough \ empty-body strict-overflow sequence-point maybe-uninitialized \ misleading-indentation However int-in-bool-context ( -Wnoint-in-bool-context ) seems to be available only in gcc 7 + . Example call with gcc 6 leads to a warning : /gcc-6/bin/gcc sizeof.c -Wall -Wextra -Wno-int-in-bool-context -o sizeof sizeof.c: At top level: cc1: warning: unrecognized command line option '-Wno-int-in-bool-context' Should we force all users to gcc 7 and higher (otherwise we could maybe check CC_VERSION_NUMBER in the makefile) ? Before we internally switched our OpenJDK builds from gcc 4.8 to gcc 7 we had a patch in our build-queue that disabled the -Wnoint-in-bool-context . Best regards, Matthias
