[Issue 14431] [REG 2.067.0] huge slowdown of compilation speed

[via Digitalmars-d-bugs]

https://issues.dlang.org/show_bug.cgi?id=14431

Iain Buclaw <ibuclaw at gdcproject.org> changed:

           What    |Removed                     |Added
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                 CC|                            |ibuclaw at gdcproject.org

--- Comment #8 from Iain Buclaw <ibuclaw at gdcproject.org> ---
(In reply to Martin Nowak from comment #5)
> (In reply to Martin Krejcirik from comment #4)
> > I'm not sure how relevant this is to the general compilation speed, but
> > anyway:
> > 
> > import  std.regex;
> > 
> > auto RE_VARSET = regex(r"(?<!!\w+.*)!(\w+)\s*=\s*([\w!.-]+|`.+`|" ~ `".*")[
> > \t]*`,"i");
> > auto RE_CMD    = regex(r"!([A-Z_]+)\(([A-Za-z0-9_ .:;!,@{}/*-]*)\)");
> 
> This spends most of it's time in CTFE interpretation.
> I get a 5-10% speedup when compiling v2.067.0 on my machine vs. using the
> released binary, most likely because of a newer gcc 4.9.2 vs. gcc 4.7.2 on
> the debian build image.

Maybe the speculative devirtualization in gcc-4.9 is in some part responsible
for that.  Just thinking out loud...

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