gratilup

4 ms·

1.
by gratilup 7y ago
Don't even need Incredibuild, even MSBuild or just plain /MP option in VC++ can take advantage of it. A build from VS of the Unreal Engine 4 client takes around 2 min, for example.
2.
by gratilup 7y ago
They are full 256 bit wide now, that's how it can claim a 2x float perf. improvement. It also doesn't have an "AVX" offset.
3.
by gratilup 7y ago
Now imagine a Threadripper with the Zen2 cores, higher IPC and frequency would be certainly welcome. Have the 32 core 2990WX and it's an incredible CPU for compiling large C++ programs, running big test suites and never having to worry
4.
by gratilup 10y ago
As a compiler engineer, those are some of the least impressive things done by modern compilers. Why? Because there isn't anything smart behind them, it's pure pattern matching.
5.
by gratilup 10y ago
You basically just said that the Windows kernel code is beautiful, because they are using exactly the same coding style...
6.
by gratilup 10y ago
I'm the main developer of the new optimizer. It's a bit too much to say it replaces the old one, it's more of an addition. I was aware of this issue with initializing local arrays, it was on the TODO list - hopefully for the
7.
by gratilup 10y ago
The EH info looks the same when in SSA form - when building SSA the right PHIs are inserted for the values potentially defined in EH blocks.
8.
by gratilup 10y ago
Visual C++ does not use the GCC naming for flags. The flag will likely be renamed to something shorter in the final release in Update 3.
9.
by gratilup 10y ago
That's why that patterns is not applied in the new optimizer, unless the Bit Estimator proves x+1 does not overflow. After it was implemented to behave like what other compilers do, I analyzed several applications and libraries and it
10.
by gratilup 10y ago
What I meant to say is that if you have an overflow in those cases, the results of the expression is definitely not what you wanted - this is going to propagate and "damage" other expressions. Applying the optimization in that cas
11.
by gratilup 10y ago
The optimizer will be ported to .NET Native soon, it should help code quality quite a lot. The JIT is a completely different matter though: it's a different project, done by a different team - copy-paste of the source code is definitel
12.
by gratilup 10y ago
There are only a few places where the undefined behavior is exploited right now. For those cases, if there is overflow in the original expression the program is pretty much screwed anyway; they are also done by LLVM/GCC. The case that
13.
by gratilup 10y ago
I tried to have a simple example, maybe it was too simple. You are right, an OR with a constant is enough to know it is not zero. For this case the Bit Estimator also knows b = [3, 4083], writing something that takes advantage of this info
14.
by gratilup 10y ago
Hi, I'm the author of the blog post and optimizer. We had SSA since around 1999-2000, just that some important components like the expression optimizer were written before that and not updated with support for SSA. The difference is a