Hi,
I am running Mac Intel I7 post 2020 with Sonoma and clang 15.0 .
The Clang 15.0 makes c++ code running 5 times slower than it was before upgrade from Ventura 13.6 and Clang 14.3.1
The other trouble is that Sonoma does not allow to revert to Clang 14.3.1 . I do not use Xcode only command line tools .
here my options :
g++ -std=c++17 -Ofast -march=native -funroll-loops -flto -DNDEBUG -o a prog.cpp
So what happened to C++ ?
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Hello,
I Run MacOs ventura 13.6 and command line tools 15.0 on MacBook Intel I7 post 2018.
After installing clang 15.0 the performance of C++ test programs shows 4 at 5 times slower execution time compared to Clang 13.0
Has anybody observed this slow down ?
The tests using a lot of mathematical computations is compiled with the folowing command :
g++ -std=c++17 -march=native -funroll-loops -Ofast -DNDEBUG -o a atest.cpp
So I had to revert to Clang 13.0 to have reasonnable execution time .
What makes C++ code so slow ?
Hello,
Using Mac Intel Ventura 13.6 I upgrade to latest command line tools that provides clang 15.0.
Unfortunately the applications compiled with this last update are running 4 at 5 times SLOWER . Has any one the same observation ?
Here the command line :
g++ -Ofast -march=native -flto -funroll-loops -DNDEBUG -o a myprog.cpp
So I reverted to clang 13.0 to have an acceptable performance.
Hello,
On Mac Intel I update to ventura 13.6 and I use command line tools with clang 15.0. I have a test making some computations. The compiled code with this last version of clang is 4X times slower. I don't understand why or the source of this regression
my command line is :
clang++ -Ofast -march=native -funroll-loops -flto -DNDEBUG -o a myprog
No chance very slow 4 times slower than clang 13.0 . So I reverted to 13.0.
Is there a way to improve the performance or should wait clang 16.0 or above ?