Performance problem in reverse algorithm
Fool via digitalmars-d-ldc
digitalmars-d-ldc at puremagic.com
Mon Aug 25 11:04:01 PDT 2014
On Monday, 25 August 2014 at 16:49:34 UTC, Kai Nacke wrote:
> On Sunday, 24 August 2014 at 16:45:12 UTC, Fool wrote:
> The speed of binaries produced by ldc is roughly the same as of
> binaries from clang++. That is no wonder as both use the same
> LLVM machinery.
Yes, that's what I thought. Probably, there is something strange
going on in the depths of LLVM.
> You could try the LDC_never_inline pragma
> Unfortunately, general attributes are not yet implemented in
> LDC (see issue #561,
Introducing pragma(LDC_never_inline) slightly improves execution
time of the ldc result to 5.4s. Still, this is more than three
times slower than the fast version produced by clang++.
> That is an instance of issue #683,
> https://github.com/ldc-developers/ldc/issues/683. Sorry for
No problem, thanks for the info!
> I will try to check this but it will take some time as I am
> busy with some other D related tasks.
Thanks, there is no time pressure. I compared ASM and LLVM-IR of
the fast and slow versions using clang++. Unfortunately, my foo
in this area is non-existent. The only thing I noticed is that
the fast version has significantly longer ASM and LLVM-I
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