http://gcc.gnu.org/bugzilla/show_bug.cgi?id=53958
Bug #: 53958 Summary: set_slot_part and canon_value_cmp using 90% of compile time Classification: Unclassified Product: gcc Version: 4.7.1 Status: UNCONFIRMED Severity: normal Priority: P3 Component: c++ AssignedTo: unassig...@gcc.gnu.org ReportedBy: ncahill_...@yahoo.com Created attachment 27786 --> http://gcc.gnu.org/bugzilla/attachment.cgi?id=27786 Source code showing problem. I've got a situation here where the compile basically stalls, and a profiling sample from a late enough stage shows 92% of time going to set_slot_part and canon_value_cmp (from var-tracking.c). So I guess the assumptions about the size of some data structure are being invalidated. I am unable to give a small testcase, but I've attached the preprocessed code that causes this condition. The flag that seems to give the trouble is -fno-omit-frame-pointer. Without this flag, it completes in reasonable time. This is with gcc 4.7.1, i686-pc-linux-gnu, 32 bit. Commands: cc1plus -v b.c -dumpbase b.c -march=athlon -mtune=pentium2 -auxbase-strip b.o -g2 -O2 -std=gnu++98 -fno-inline -funroll-loops -funswitch-loops -fno-strict-aliasing -fno-omit-frame-pointer gcc -pipe -g2 -fno-omit-frame-pointer -O2 -Werror -fno-strict-aliasing -march=athlon -mtune=pentium2 e -funroll-loops -funswitch-loops -Wall -Wcast-align -Wundef -Wformat-security -Wwrite-strings -Wno-se -Wno-conversion -Wno-narrowing -pthread -pthread -x c++ -std=gnu++98 -Woverloaded-virtual -c b.c -o b.o Thank you. Neil.