https://issues.dlang.org/show_bug.cgi?id=18114
Martin Nowak <[email protected]> changed: What |Removed |Added ---------------------------------------------------------------------------- CC| |[email protected], | |[email protected], | |[email protected] Hardware|x86 |x86_64 Summary|dmd 2.078-beta1: regex |[Reg 2.078] regex |performance regression |performance regression OS|Mac OS X |All --- Comment #5 from Martin Nowak <[email protected]> --- Introduced by https://github.com/dlang/phobos/pull/5722. There were some major internal changes in the std.regex module. I see a 60% increase in issued instructions for the 'abc' regex, but also much better ILP with this WIP PR. https://github.com/dlang/phobos/pull/5981 There are quite a lot of very slow LOOP instructions used to copy fat struct parameters around. Those seem to clog the pipeline. https://github.com/dlang/dmd/blob/7f43f0f88df876aec60a22a6a74940020fb1ef50/src/dmd/backend/cod1.c#L4046 https://stackoverflow.com/questions/35742570/why-is-the-loop-instruction-slow-couldnt-intel-have-implemented-it-efficiently#35743699 Whether or not the increase in instructions with better ILP is intentional or another bug, I don't know. Guess Dmitry can help to figure this out. --
