https://gcc.gnu.org/bugzilla/show_bug.cgi?id=70768
Markus Trippelsdorf <trippels at gcc dot gnu.org> changed: What |Removed |Added ---------------------------------------------------------------------------- Status|UNCONFIRMED |RESOLVED CC| |trippels at gcc dot gnu.org Resolution|--- |INVALID --- Comment #1 from Markus Trippelsdorf <trippels at gcc dot gnu.org> --- (In reply to James Almer from comment #0) > Created attachment 38332 [details] > Preprocessed output > > The attached preprocessed output (Created from the source using GCC 5, 6 and > 7 for the purpose of this ticket) takes almost twice as long to compile > using GCC 6.0.1 RC and especially GCC 7.0 compared to GCC 5.3 on a linux > x86_64 machine with 2gb of RAM. > > GCC 5.3 performed the best for all three preprocessed files. > GCC 6.0.1 performed about the same as GCC 5.3 using the gcc5 preprocessed > file. It however trashed my HDD a lot trying to compile the preprocessed > output from both GCC 6 and GCC 7, and took longer to finish them. This may > hint at increased RAM usage and explain the odd time values, but i didn't > check. > GCC 7 performed the worst across the table, even with the gcc5 preprocessed > file. Well, you simply need more RAM to compile this testcase, because gcc-6 uses slightly over 2GB peak, so your machine starts swapping. On my machine (with 8GB RAM) gcc-6 is actually slightly faster. (For gcc-7 you need to configure it with --enable-checking=release to compare timings.)