Msvc vs gcc performance. 57x as long to run), on Ice Lake it's 2.

Msvc vs gcc performance Making MSVC compiler GCC complient? 2. c Benchmarks telling that there is a significant performance gap between GCC and Clang are coincidental. 32. GCC is a set of the full compiler, where Clang isn't. I am no see any advantage current to keep use msvc inside visual studio, it seem me clang is the superior do in all way. X series is getting better and better, but is not yet comparable to MSVC one). It's by no means a general statement on ICC's performance, but the results were sufficient for us to go ahead with GCC 4. This is because the LLVM/Clang compiler uses the MSVC APIs and libraries implementations. So, after check, I made a conclusion that problem is MSVC. but it is not fully up to date and it has some performance problems. Though, many tests show essentially different CPU time between MinGw SEH and MSVC 2010 (mostly within +-50%), but these deviations go in both directions and have not much effect on the average. – What is the difference between Visual C++ and GCC C++? I currently know C# and am looking at learning C++, but there are two versions?! I'm looking to mainly be a game developer with possibly some software development on the side. 57x as long to run), on Ice Lake it's 2. The toolchain is not nearly as powerful or flexible as Mingw-w64. I'm getting 70% of the peak flops with GCC and only 50% with MSVC. . Also,It seems msvc has faster dynamic linking while I need to write some addon for NodeJS. MSVC gives me at least 10% more performance in graphical applications. c. With GCC and clang, my code will be auto-vectorized if I compile with -O2 -ftree-vectorize -march=XYZ? -O3 -march=XYZ ? Hi all- quick question, but first a little backgroundI’ve been using CUDA to speed up some data reduction codes for my institution. Is there any simple way to tell MSVC compiler to treat . VS 2019 improves frame time up to 2. dll, while msvc links to the hot-and-sexy ucrt. In answer to Xentrax: Your statement regarding MSVC does not seem to match with my observation. This included features like progressive population of IntelliSense results and faster symbol searching. For my testing I ran the C implementation and the AVX implementation on both platforms and got the following timing results: In Visual Studio: C Implementation: 30ms. My naive benchmark shows clang's executable run time is about 10% of the MSVC's runtime. So 1. 2 MSVC /FA GCC equivalent. The program involved the use of lambda expressions and raised the question of which compiler was correct. Is it possible to trick MSVC into producing better assembly? I've looked at Compiler Explorer but my experiments haven't made much " Different compilers gcc 7. This can lead to issues with performance, as the preprocessor has to do a lot of work to expand the macro each time it is called. cast]/p4, all quotes are from N3936):. Clang/MSVC Divergence. mingw use gcc , no that easy to use in visual studio. 8. It's essentially no On the AMD side, the Clang vs. If you want your access to always be bounds-checked, then you need to use std::vector::at(). When diving into the intricacies of template argument deduction in C++, one might face various discrepancies among different compilers. If they didn't they would only work on one specific version of Windows. Most Linux distributions will provide a pre-built OpenCV library well Both GNU and MSVC must load the same . So does anyone have any up-to-date info on compiler performance on MSVC++ vs MinGW/ GCC? (Specifically the generated code) This thread is archived New comments cannot be posted and votes cannot be cast you'll see that they're actually working really hard to modernize MSVC, adding the latest C++ features, and performance improvements. I think I may have isolated the difference to how they both convert the following three intrinsics. 3 I am trying to get decent performance out of MSVC for this code. Score: Clang: 2, GCC: 0, MSVC: 1. MSVC follow standard when work with . This article focuses on C++11, C++14, and C++17. I got curious as of how exactly GCC emits these strings. Compile time comparison between Windows GCC and MSVC compiler. 6 on a i7-3612QE. The MSVC runtime DLLs also have different versions with the same interface and within the same "release", that are distributed with patches. GCC 13 Compiler Performance On Intel Raptor Lake For those wondering how the recent releases of the Clang 16 and GCC 13 are competing for the fastest generated binaries of these leading open-source compilers, here is a fresh round of benchmarks from an Intel Core i9 13900K "Raptor Lake" system looking at the performance for For instance you can aim for your code to work on x64 linux and windows, gcc clang and msvc, latest version , or from version x upwards and ignore everything else. With some benchmarks, it is seen that lld is faster than ld and even the newer ld-gold. With both GCC and LLVM Clang, the benchmarks were carried out three times with varying CFLAGS/CXXFLAGS. x directives for multi-threading and vectorization. For all intents and purposes we're usually not differentiating between the name of the executable and the name of the compiler so nobody says MS-cl, everyone just says MSVC. It depends very largely on how code is written. cpp. Since addon should work on Windows, I need to compile it with MSVC. I can't rename all them to . Surprisingly, I found gcc beat llvm-gcc for both cases. " Latest vs2019 C++17, LLVM vs MSVC compilers (64-bit): sequential vs parallel computation test -> MSVC better? So using the same test C++17 code with two different release targets (both optimized for speed), I get similar results (even if often a bit better with MSVC) except for sequential sums. 3. This can be important if working with C libraries. I also might not be using the optimum compiler settings since I am new to GCC. (icc be damned). AVX Implementation: 5ms. gcc -O3 example. However, MSVC has a template parsing model that delays nearly every lookup to instantiation time, which is part of phase 2. GCC is wrong in the second case. To achieve this there is really Modules support is pretty buggy in clang and gcc (I haven't tried msvc modules). c and . @Infinity77: The question you asked was why later GCC versions have worse performance on the messy C code created by Cython for your hard-to-optimize source, and/or One big thing that GCC loses against MSVC is WPO (Whole Program Optimization). MSVC has "checked iterators" for std::vector, which perform a number of useful checks. With regards to runtime performance, our optimization framework got a big rewrite with VS 2015 Update 3. An expression e can be explicitly converted to a type T using a static_cast of the form static_cast<T>(e) if the declaration T t(e); is well-formed, MinGW GCC; Clang-cl (MSVC toolchain) MinGW Clang; LTO also depends on the linker used. However GCC C++ seems to allow this kind of construct through some kind of an extension. The timeline in Figure 1 shows the existing C++ standards, with the exception of C++03, which was only released as a bug fix for C++98 in 2003. GCC performance has reached the stage that in many instances they now deliver similar performance But in select instances, GCC still was faster: GCC was about 2% faster on the FX-8370E Does every source code that can compiled in GCC also can compiled in MSVC or they have some difference in implementation of C/C++ standard? Skip to main content. 18 on ICL. the many different llvm obfuscator projects are use clang, and clang support inline x64(msvc no this). c file as C++ ones? There were also additional nice boosts to the performance from Clang 17 over GCC 13. 知乎，中文互联网高质量的问答社区和创作者聚集的原创内容平台，于 2011 年 1 月正式上线，以「让人们更好的分享知识、经验和见解，找到自己的解答」为品牌使命。知乎凭借认真、专业、友善的社区氛围、独特的产品机制以及结构化和易获得的优质内容，聚集了中文互联网科技、商业、影视 So the fundamental disadvantage of gcc vs. The same applies to the rest of the Last week I posted a number of fresh GCC vs. For example, looking at a specific run of the OOPACK benchmark by Charles Leggett:. So, I don't understand, why MSVC produce so slow program. 7 Optimized Execution Time. A is 16byte aligned making it 0x20(32) B is also 16 byte aligned, but is either also 0x20(32) on GCC but on msvc it is 0x30(48) is there a way to force the msvc to pack the data like GCC is? which size of struct member alignment in VC bring performance benefit? 3. GCC 13 Compiler Performance On Intel Raptor Lake For those wondering how the recent releases of the Clang 16 and GCC 13 are competing for the fastest generated binaries of these leading open-source compilers, here is a fresh round of benchmarks from an Intel Core i9 13900K "Raptor Lake" MSVC actually got much The inside of your loop will have its hands full with printf(). I'm using VS 2010 and see the compiler generating a "jne" when using a normal if. Like on AArch64 Linux and on AMD x86_64, there continues to be very healthy competition between these open-source compilers for which offers the I compared gcc and llvm-gcc with -O3 option on hmmer and mcf in spec cpu2006 benchmark. A recent code snippet shared on a programming forum clearly exhibits such divergence, particularly between GCC, Clang, and MSVC. It is possible to separate debug information on gcc as well, however doing so is not as convenient and requires some extra steps . In this article, we will explore the differences between MSVC, GCC, and Clang when it comes to implementing constexpr constructors in C++20. Also, what version of gcc? On linux I have extensively tested several versions of gcc (with a lot of effort put into tuning command line switches) against the Intel 10 compiler. 57 c/byte of output. Huge performance difference of a C++ program (compiled with GCC) under Mac and Linux. It misses a lot of basic optimisations that you'd expect, and trips up over pretty much everything. 8% over VS 2017; An LTCG build improves frame time up to 3. memory) throughput rather than computational throughput. And linux also have a "release As part of our ongoing benchmarks of GCC 11 vs. GCC didn't recognize the second error, and the "expected ';' before 'return'" errors from MSVC and GCC are like saying that to climb a tree, I must put the tree below me. Practically both are well optimized, however, LLVM IR is much more robust and modular, than As it can be seen, average performance of MSVC 2010, 2017, and MinGw-w64 SEH is nearly the same. Even if the compiler is now free as in free beer, Visual Studio is still a business unit, and a rather large one, last I checked. 9. We’re taking advantage of this new optimization framework in VS 2017 to make your code faster. 9 [expr. While In the case of basic arithmetic, it may be measuring cache (i. Round 2: The Missing Brace So 0. In the question “What are the easiest to use C++ compilers and I've noticed msvc misses a lot of simd optimisations that clang and gcc catch. Hot Network Questions Is this a correct implementation of atomic reference counting in C? Elementary consequences of famous technical Then build gcc and winpthreads without modification: make gcc winpthreads Now, edit mxe/src/gcc. So if you are using a non-Microsoft compiler (like Clang or GCC), you still use ucrt, but FastTrack performance comparison between Linux and Windows The Linux version was compiled using the GCC compiler with the default release flag of Qt. Also something weird, iostreams are super slow in msvc, but in gcc printf is slower about half the time. In this blog The only advantage is that you get a statically-linked CRT — versus linking against an old msvcrt. The "fundamental difference" is that gcc tries to preserve the binary interface between releases. 33. It is technically true, but it is stupid. Let’s have a look and explain these results. For instance, import libs are still mandatory (for When comparing GCC vs Microsoft Visual C++, the Slant community recommends Microsoft Visual C++ for most people. I think the question is specific enough. (Unroll loops or don't unroll loops, that is the question ;) ). dll. 46 Difference in performance between MSVC and GCC for highly optimized matrix multplication code. LLVM Clang compiler performance benchmarks using an AMD Ryzen Threadripper PRO 7995WX (Zen 4) system using the HP Z6 G5 A workstation running Ubuntu Here's a short answer regarding GCC -- there's an extensive list of different benchmark results available on their home website. What could be the reason for this major performance difference? MSVC: ~36 seconds GCC: ~1:10 minutes. Microsoft delivers a brand new set of libraries with each release. Are you one of those programmers still debating about Clang or GCC? Then this awkward an delicious video is for you! Both Clang and GCC are pretty good#pr Although it's not clear if Clang routinely generates ASM intermediate files, as gcc does, or only when asked by using -S. 68 c/byte or 0. There are of loads of C compilers for Windows; it's not all MSVC. GCC: Token Pasting Understanding Compiler Behavior: Clang vs GCC vs MSVC. Check for floating-point strictness settings: /fp:strict vs /fp:precise vs /fp:fast. It's hard to say why one compiler would be better than the others. Program performance is affected by the choice of the compiler. In fact, not until recently could you compile ffmpeg with MSVC. The first relevant item is that all msvc, LLVM/Clang and Visual Studio ClangCL are using the same runtimes. gcc has more technical usability features because the people using it can adjust the technical parts they care about (or need) and hate (like the plauge) writing docs thus the docs are more shitty engineer type then Clang is fairly strictly conforming to the two-phase name lookup. The answer to that is, Microsoft split their CRT into two parts, one which was specific to their compilers (vcruntime), the other generic to all compliers (ucrt). . Windows is obviously not an OS aimed at programmers. Reply reply [deleted This is a good answer, but it doesn't explain the relationship between ucrt and vcruntime, which the question was also asking. 5 Performance comparison between Windows gcc compiled & Visual Studio compiled. But it's more compatible with other platforms in some cases. but from what I For those wondering how the recent releases of the Clang 16 and GCC 13 are competing for the fastest generated binaries of these leading open-source compilers, here is a fresh round of benchmarks from an Intel Core i9 The Gcc and Clang compilers are clearly the best when it comes to code optimization. 52 c/B of output over large buffers for planar data (at least if L2 cache or maybe L3 to keep up with memory bandwidth). e. 10 64 bit, Cython 0. lib. Clang is better than Gcc in several respects, but it has a tendency for excessive loop unrolling, which is a waste of code cache. The OOPACK kernels consist of 4 programs to measure the relative performance of C++ compilers vs C compilers for abstract data types. Now obviously you can compile this in C as the standard supports dynamically sized arrays. For maximum performance with MSVC use /Ox plus architecture specification like /arch:AVX2. As soon as you include the C++ standard library like iostreams msvc starts ballooning. I use an up-to-date Visual Studio (2022) with the latest ClangCL component With our recent 1. Personally I like GCC and Clang/LLVM more because of better portability for Linux or MacOS for example, and that I personally think that both GCC and Clang/LLVM give better diagnostic messages about GCC with LTO was running roughly 3 times faster than ICC without LTO. Is it because the -O3 has different meanings? How should I establish the experiments to get a fair comparison? BTW, I did the experiment by ONLY changing cc in the makefile. 75 c/B or 1. cu files so everything could be compiled MSVC vs. And graphics stack in linux is getting better year at year. In short: Clang is correct (though in one case, for the wrong reason). I'm seeing a big difference in performance between code compiled in MSVC (on Windows) and GCC (on Linux) for an Ivy Bridge system. The High Performance Parallex (HPX) library , for instance Phoronix: LLVM Clang 16 vs. Find the line that starts with $(PKG)_DEPS := and add winpthreads to the end of the line. vs. g. I'm seeing a big difference in performance between code compiled in MSVC (on Windows) and GCC (on Linux) for an Ivy Bridge system. This is an "import library". – ab Fresh investigation shows the difference in std::mutex implementation in latest versions of MSVC compared to MSVC 2013. static. You can turn on some of these types of checks in GCC by compiling with -D_GLIBCXX_DEBUG. So, my questions are: Why there is huge performace difference between my 'strchr_x' and the standard library's 'strchr' in GCC? Why there is this huge performace gap between in GCC and Clang? What is the difference between x86_64-pc-windows-gnu and x86_64-pc-windows-msvc from a user perspective? Essentially, other than the obvious difference of compilers, gnu links to the old-and-lame msvcrt. Understanding these differences can help developers write more effective and portable code. Structure member alignment in GCC. Let's start from static_cast (§5. can use clang driver too like this Using Linker backend – GCC Vs Clang is the most prominent here. Difference between GCC binaries and MSVC binaries? 6. As the project grew a little larger, I saved separate sources belonging to the same project as . When I first started, to get things up and running quickly, I had all my source in one large . c files compiling well in GCC and not in MSVC due to this. MSVC is wrong in the first case. The MinGW standard library printf() is slower than the one provide by Windows API. lld-link seem support most msvc link features too. If a developer or a group of developers is exclusively using GCC then the program can be expected to run slightly faster with GCC than with Clang, and vice versa. but linking against MSVC-built libraries will be even more weird in that case. cpp source files. Here is a link with more information: Compile time comparison between Windows GCC and MSVC compiler. It is slow on MSVC 2010 and older GCC (below 4. So on Skylake, clang is 2. vc+win, icc+win were pretty close. The question at hand is which compiler, Clang or GCC and MSVC, is correct when it comes to accepting or rejecting a program that uses the new keyword. 65x faster. I tried the following compilers/STL and they showed the same behavior: MSVC 2019 (SDK 14. 4 BENCHMARK: Lua vs vs LuaJIT vs C (MSVC, GCC, LLVM) vs Java vs Perl vs Javascript vs Python vs C# (. clang and clang++ are then the compiler executables used. This should however only really matter if you write really performance sensitive code, e. The compilation time for large projects with heavy C++ templating. But if you carefully pick your data and compare different compilers, you can get a performance boost of more All of the GUI solutions for the G++ or MSVC seem quite cumbersome in comparsion, e. As part of the various end In this article, we discuss the differences between MSVC and GCC in handling recursive macros. cpp The first surprise to me was how similar they are - only on the MS compiler is there an appreciable performance increase going from double to float. They were done on an i5-12600 CPU OS Win 11 pro 64. However, in comparison, there are several things you can see. On another note, The VS vectorizer lacks quite a bit of features when compared to gcc or clang. MSVC doesn't allow this kind of statement, so we were a bit puzzled. GCC allows to declare variables anywhere in function body even if source file is . In win64 you are more likely to see gcc generating better code than those others. Clang can be (and often is) built against the MinGW-W64 ecosystem in such a way that it's a drop-in replacement for MinGW gcc and g++ (i. For the sake of benchmarking, I have compiled the exact same module with MSVC, GCC 8, GCC 11, GCC 12 and GCC 13 on Windows 10 64 bit, Python 3. Note: the KERNEL32. I have GCC 11: 54 s: AWS/Linux: Intel Ice Lake processor: LLVM 14: 54 s: There may be a significant performance difference between Debug and Release code (e. Performance may be affected by cache etc. Thanks, Bo With MSVC, By default, the Auto-Vectorizer is enabled and picks up appropriate instructurion set for fastest vectorization. Nowadays you can, We measure two aspects of the compilers’ performance: The speed of compiled C/C++ code parallelized with OpenMP 4. wxWidgets builds a 30MB DLL and still is a lot of work to use; make a New MFC application in VS express and literally it makes 30 files of boilerplate Performance difference was about ~15% which was very noticeable in that application. 57x as fast (MSVC takes 2. dll is always a system runtime dependency, in all cases, it has been omitted in the table. These days there are few differences between compilers (MSVC, GCC, Clang/LLVM). 30133) MSVC 2022 (SDK 14. The code does dense matrix multiplication. For 32 bit situation is different, msvc always slower and I not release it. 5%, in large part a result of the compiler automatically generating FMA instructions for scalar, and now in 16. I dont have low level details about it but i suspect the cause is a combination of better optimization (ej, copy on write memory when fork a process), api exposed (system-v api vs win32) and complexity (linux boxes often run less process at idle state). 0, vector operations. Build tool – Perhaps another place where Clang Vs GCC difference comes to the forefront. The difference between MSVC and GNU is user32. 2 on Meteor Lake for workloads like the LC0 deep learning chess software, miniBUDE HPC, and the SMHasher crypto test. Those flags included: When I use the 'strchr' method in the standard library; GCC's run time reducing to 0. Also I believe that GCC in many (but not all by far) circumstances is able to produce the fastest code of all three, though the difference is almost negligible. mk. Now, recompile gcc and enjoy your C++11 threads. Like gcc and Clang for a start. There were some part where I used parallel threads which just worsened the performance to >35s. 10 Linux plus a look ahead in using the latest GCC 14 and LLVM Clang 18 development snapshots as of this week. GCC 13 vs. 31629) Both of them are using SRW locks for std::mutex implementation by default. 015625 seconds. MSVC’s new SSA (static single assignment) optimization framework opens up new possibilities for how we can make your code run faster. Microsoft Visual C++ (MSVC), a component of Microsoft Visual Studio (the IDE as a whole) Intel C++ compiler Understanding the Difference: MSVC vs GCC/Clang C++20 constexpr Constructors. LLVM Clang 12 given these fresh open-source compiler releases, today's comparison is looking at the Core i9 11900K "Rocket Lake" performance. Try building with __USE_MINGW_ANSI_STDIO set to 0, either by using compiler flag -D__USE_MINGW_ANSI_STDIO=0 like this. Why does Rust require a C++ toolchain to produce a Rust binary, while languages like Go do not have this requirement? Performance difference Rust and C++. Learn how to optimize performance by sharing Azure Authorization Code Flow In a recent discussion on a coding forum, a user shared a program they wrote that compiled successfully with MSVC but failed to compile with GCC and Clang. Might be worth checking if there's a significant codegen difference where you're measuring a performance The entire module's computation took 30s on msvc. 2 Difference between GCC binaries and MSVC binaries? 0 Drastic performance difference across C++ Visual Studio usually doesn't provide the latest version Note that VS tries to provide the latest version of Clang/LLVM in a timely manner, but we need to wait for the final release version, do installer work and run testing, and then we're subject to the latency in the VS release pipeline (after a change is merged, it takes a while before it appears in a VS Preview, and then more . 0 GCC handpicking Optimizations. In GCC: C Implementation: 9ms. dll per Mingw-w64 — though historically Microsoft's UCRT has been kind of buggy, and those bugs then get baked into your binaries. Let's take a closer look at the code snippet in question: — Optimizing Memory Layout for Performance with 2D Shapes in C++ GCC may better optimize for i7 and MSVC for Core 2 Duo or vice versa. Hi, I'm working on a Windows pc and I'm currently using the msvc toolkit (recommended for building Python cffi modules). Clang uses LLVM in the backend. 2 FMA performance compared to naive calculation. 29. 3 (from MSYS2) or MSVC 2017, performance very close, usually msvc little bit faster, you can try both. Let's dive deeper into the issue and explore the nuances of lambda captures. The libraries I'm linking against are: Boost; Catch2; Loguru; MSVC code generation quality is almost on par with GCC and Clang. For clang and GCC we always mean the C++ compiler, we're just lazy and drop the "++". GCC is between the two and is typically about 25% of MSVC. If I am making a Windows program I will be using MSVC even though I am 100% in love with gcc. AVX Implementation: 57ms Clang clearly won here, with MSVC in second. It doesn't quite support C99 and probably never will. GCC uses autotools and MSVC produces significantly better binaries than gcc even with -March and -mtune enabled in gcc. Clang/GCC on Godbolt. An estimated 95 percent of all C++ developers rely on the GCC, Clang, or MSVC compilers. 2% compared to the default unity build; Using AVX2 over AVX shows a significant frame time improvement, up to 8. We used two Windows compilers: MSVC 2019 used for the FastTrack stable release, and MinGW_64 (GCC for Windows. The Cygwin64 version of Clang is using a medium memory Phoronix: LLVM Clang 16 vs. I'm not able to find the numbers right now for GCC without LTO, but I recall it was still faster than ICC. MSVC already has it mature for quite a long time, while AFAIK GCC is still moving toward maturity (4. On gcc without multi threading, computation took 4~5s and with multi threading, the gcc has way better C support than MSVC. This delay is why your example would compile with MSVC(which is non-conforming) and not in clang. *. Also, gcc has the proper coroutine support header but limited optimisations, while clang has powerful optimisations for coroutines but doesn't work with the libstdc++ header and the libc++ header is still under the experimental subdirectory last time I checked. Flags: -O3 -mavx -m64 -march=corei7-avx -mtune=corei7-avx. This is because MSVC has its own set of compiler options and does not support the -Wextra flag. 2. Clang 17 were tested as what's readily available on Ubuntu 23. ). But when using an else instead, the compiler Visual Studio 2015 has got a lot of changes on the C++ compiler side and I'm looking for a benchmark/performance comparison between the Intel C++ compiler and Visual Studio 2015 ! About performance, I mean the performance of the generated code, something like this : gcc+linux; icc+linux was the very best. In my view, the difference is that MSVC is (or at least has been historically) a Microsoft product. See results below. This feature can help improve the performance of your code by reducing runtime overhead and allowing for more efficient A place for all things related to the Rust programming language—an open-source systems language that emphasizes performance, reliability, and productivity. cu file. GCC uses ld as the linker with support for ld-gold. make gcc Note that "Clang on Windows" does not necessarily always mean "clang-cl as a replacement for cl in the context of an MSVC toolchain". with GCC and binutils and everything, kinda like if you are developing on Linux. And find --enable-threads=win32 and replace it with --enable-threads=posix. I can say on Windows / Xbox Series X (MSVC) vs PS5 (clang), when using profile guided optimizations MSVC is considerably better (around 10% in our project) after accounting Let us compare their performance characteristics with a fast string transcoding library (simdutf). MSVC at 14 cycles / iter on SKL or 12. GCC uses its own IR generation where Clang uses LLVM IR. MSVC or Intel is gone. So, while the msvc people are really fantastic, and they've made massive strides from a conformance perspective, msvc also by far produces the worst code of the gcc/clang/msvc trio in my experience. Clang uses lld as its linker. NET CLR, Mono) vs Ruby vs R - DNS/benchmark-language Understanding Template Argument Deduction: GCC vs. 19 release, performance was our biggest focus for the C++ Extension in Visual Studio Code. I have a huge number . But after compilation I discovered that addon was slower than original program. While MSVC allows for certain code to compile, enabling the -Wextra flag in Clang or GCC on Godbolt may result in compilation errors. Fedora Linux 15 w/ gcc 4. Does GCC allocate it at declaration time and is this allocation done on the stack? g++ is GCC's C++ compiler executable. , between 5x to 15x difference). As for "little differences" between vc++ and gcc I would like to mention that by default vc++ emits debug information in a separate file while gcc will squeeze it into executable. Stack Overflow You could list a few example that compile in one compiler but not on another or some method to port from GCC to MSVC. GCC and clang/llvm, on the other hand, are treated and developed more like infrastructure. gcc -O3 -Ofast -march=native -mavx -mfpmath=sse benchbasic. I think it worth to report such performance gap between clang-cl and native msvc cl for the release mode at least with minimal reproduce code. PGO may depend on the standard library used (libc++ or libstdc++), but we will try to use the most common combinations of compilers and linkers. Often, for performance reasons, it is better to ensure bounds checking outside of your loop and then use Both GCC and Clang are well-matured compilers. vkqfwme wuzves vljwq ufjl qdt vdwgdx iacnw hbs xeqfs hbzq