[cfe-dev] Compilation time regression?

[Rafael Espíndola]

On my machine I got

$ time ./clang-3.3 -cc1 -ftemplate-depth 512  proto.ii -o test.o
real    0m2.932s
user    0m2.889s
sys     0m0.035s

[espindola at desktop llvm]$ time ./clang-3.4 -cc1 -ftemplate-depth 512
proto.ii -o test.o
real    0m0.918s
user    0m0.873s
sys     0m0.042s


Can you check if 3.4 fixes the problem for you? If not, please open a
bug with the preprocessed source code.


On 23 November 2013 17:00, Bart Janssens <bart at bartjanssens.org> wrote:
> Hello,
>
> I recently upgraded from "Apple LLVM version 4.2 (clang-425.0.24)
> (based on LLVM 3.2svn)"
> to "Apple LLVM version 5.0 (clang-500.2.79) (based on LLVM 3.3svn)"
> and noticed a large increase in compilation time for our code, which
> relies heavily on Boost Proto.
>
> The problem is confirmed using a small test (attached), yielding the
> following compilation times:
> Clang 3.2 OS X binaries from the site: 1.69 s
> Clang 3.3 OS X binaries from the site: 7.93 s
> The LLVM3.3 Apple version: 10.66 s
>
> Is this a bug, or is there some setting that can be changed to speed
> up the compilation of this kind of template code? The new version
> seems to use only about half as much RAM as before, so maybe there's
> some memory/speed trade-off?
>
> Kind regards,
>
> Bart
>
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