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Clang 15.0 produces slow c++ applications

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 ?
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by djm44.
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Clang 15.0 make c++ code 5 times slower than Clang 14.3.1

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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Mac Intel Ventura 13.6 command line tools

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.
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mac intel last clang 15.0 very slow compiled code

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 ?
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by djm44.
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