hubicka

3 ms·

1.
by hubicka 8y ago
It is Google's blogger.com. I am not very advanced user of it and generally just use whatever it provides for me. The link is off. This link http://hubicka.blogspot.com/2018/12/even-more-fun-with-build... ren
2.
by hubicka 8y ago
GCC was designed to be extensible and portable (after all it ended up ported to more architectures than any other compiler). The political limitation was more subtle. Originally FSF did not want to make it easy let GCC store its intermedia
3.
by hubicka 8y ago
I have re-tested on my skylake notebook and updated the blog. It confirms darn old CPU I use as my benchmark machine. Maybe it is bit more sensitive to the difference which is expected for non-server CPU. GCC does "almost full LTO&quot
4.
by hubicka 8y ago
I would be happy to help with solving GCC related issues and look into performance regressions relative to clang (I am still in process of looking into -O2 performance and plan to set up talos next)
5.
by hubicka 8y ago
You need to explicitly ask for it via attribute, no automatic multiversioning is done (yet) and it would be more for -Ofast than usual -O2 builds I guess.
6.
by hubicka 8y ago
Hehe, nice to see you :) Yep, I have code layout pass in my tree for a while, but because I was never really able to measure off-noise improvements it is not in the tree, yet. I hope to make more sense of it with help of CPU counters which
7.
by hubicka 8y ago
You can try the binary on your CPU. This particular workload does not make much difference between modern CPUs. I just tried the Sunspider benchmark on my skylake and it has similar outcomes as reported, but there is more noise since it is
8.
by hubicka 8y ago
I would be interested to know what cache aware code layout optimizations are available in LLVM. I personally know of none. GCC is bit simplistic in this sense (it does reorder functions based on profile feedback and execution time) and I pl
9.
by hubicka 8y ago
There are several independent things - first how you set -O2 defaults in your compiler. This is a delicate problem since you need to find right balance of code size, compile time, robustness of generated code (do not trigger undefined effec