https://gcc.gnu.org/bugzilla/show_bug.cgi?id=65765
Bug ID: 65765 Summary: Compiling Firefox with GCC 5 leads to broken javascript engine on x86-64 Product: gcc Version: 5.0 Status: UNCONFIRMED Severity: normal Priority: P3 Component: ipa Assignee: unassigned at gcc dot gnu.org Reporter: mh+gcc at glandium dot org Created attachment 35314 --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=35314&action=edit reduced.tgz When building Firefox with GCC 5 [1], some parts of the test suite fail because of what might be a compiler bug. It seems to be involving __attribute__((cold)). Dan Gohman got a reduced testcase, attached here. Unpack and build with g++ -O2 *.cpp, then run a.out. This doesn't happen at -O1, or with -O2 -Dcold=. 1. GCC 5.1.0-RC-20150412, compiled with "--enable-languages=c,c++ --disable-nls --disable-gnu-unique-object --enable-__cxa_atexit --with-arch-32=pentiumpro". I've also reproduced with the reduced testcase with a snapshot of 5-20150111 (building Firefox with that snapshot fails for other reasons, unfortunately).