On Mon, 15 May 2023 09:30:52 GMT, Kim Barrett <kbarr...@openjdk.org> wrote:
>> /data/d042520/xlc17/jdk/src/hotspot/cpu/ppc/c1_LIRGenerator_ppc.cpp:426:97: >> error: shifting a negative signed value is undefined >> [-Werror,-Wshift-negative-value] >> I reverted my change in c1_LIRGenerator_ppc.cpp and added >> shift-negative-value to the DISABLED_WARNINGS_clang in CompileJvm.gmk. >> >> ad_ppc.cpp:18388:10: error: converting the result of '?:' with integer >> constants to a boolean always evaluates to 'true' >> [-Werror,-Wtautological-constant-compare] >> assert(VerifyOops || MachNode::size(ra_) <= VM_Version::has_brw() ? 16 : >> 20, "bad fixed size"); >> ^ >> Should I also add tautological-constant-compare to DISABLED_WARNINGS_clang >> in CompileJvm.gmk or where else? > > I see, so `size` is kind of macro-like, and is just textually splicing its > argument expression into another expression. > And without the added parens the resulting full expression for the assert > isn't checking what's intended, due > to operator precedence. > > This is in generated source; it might be better to find the code generator > (somewhere in adlc) and change it > to add appropriate parens, as there may be other similar places (both here > and for other platforms) that > aren't doing what's intended but are not triggering warnings. Such a fix of adlc is probably out of scope for this change though. We should probably have a separate bug for that. ------------- PR Review Comment: https://git.openjdk.org/jdk/pull/13953#discussion_r1193581173
