了解汇编程序的原因之一是，有时可以使用汇编程序来编写比用高级语言(特别是C语言)编写的代码性能更好的代码。然而，我也听人说过很多次，尽管这并非完全错误，但实际上可以使用汇编程序来生成性能更好的代码的情况极其罕见，并且需要汇编方面的专业知识和经验。
这个问题甚至没有涉及到这样一个事实，即汇编程序指令将是特定于机器的、不可移植的，或者汇编程序的任何其他方面。当然，除了这一点之外，了解汇编还有很多很好的理由，但这是一个需要示例和数据的具体问题，而不是关于汇编程序与高级语言的扩展论述。
谁能提供一些具体的例子，说明使用现代编译器汇编代码比编写良好的C代码更快，并且您能否用分析证据支持这一说法?我相信这些案例确实存在，但我真的很想知道这些案例到底有多深奥，因为这似乎是一个有争议的问题。
当前回答
这很难具体地回答，因为这个问题非常不具体:到底什么是“现代编译器”?
理论上，几乎任何手动的汇编器优化都可以由编译器来完成——实际上它是否已经完成，不能笼统地说，只能说特定编译器的特定版本。许多可能需要花费大量的精力来确定它们是否可以在特定的上下文中应用而不产生副作用，以至于编译器编写者不会为它们烦恼。
其他回答
Walter Bright的《optimization Immutable and Purity》可能值得一看，它不是一个概要测试，但向您展示了手写和编译器生成ASM之间的区别。Walter Bright写优化编译器，所以值得一看他的其他博客文章。
使用SIMD指令的矩阵操作可能比编译器生成的代码更快。
我曾经和一个人一起工作过，他说“如果编译器笨到不能弄清楚你要做什么，并且不能优化它，那么你的编译器就坏了，是时候换一个新的了”。我确信在某些情况下汇编程序会打败你的C代码，但是如果你发现自己经常使用汇编程序来“赢得”编译器，那么你的编译器就完蛋了。
对于编写试图强制查询计划器执行操作的“优化”SQL也是如此。如果您发现自己重新安排查询以让计划器执行您想要的操作，那么您的查询计划器就完蛋了——请更换一个新的计划器。
这完全取决于你的工作量。
对于日常操作，C和c++已经很好了，但是有一些特定的工作负载(任何涉及视频的转换(压缩、解压缩、图像效果等))几乎需要组装才能达到性能。
它们通常还涉及使用特定于CPU的芯片组扩展(MME/MMX/SSE/等等)，这些扩展是为这些类型的操作而优化的。
Actually you can build large scale programs in a large model mode segaments may be restricted to 64kb code but you can write many segaments, people give the argument against ASM as it is an old language and we don't need to preserve memory anymore, If that were the case why would we be packing our PC's with memory, the only Flaw I can find with ASM is that it is more or less Processor based so most programs written for the intel architecture Most likely would not run on An AMD Architecture. As for C being faster than ASM there is no language faster than ASM and ASM can do many thing's C and other HLL's can not do at processor level. ASM is a difficult language to learn but once you learn it no HLL can translate it better than you. If you could only see some of the things HLL's Do to you code, and understand what it is doing, you would wonder why More people don't use ASM and why assembers are no longer being updated ( For general public use anyway). So no C is not faster than ASM. Even experiences C++ programmers still use and write code Chunks in ASM added to there C++ code for speed. Other Languages Also that some people think are obsolete or possibly no good is a myth at times for instance Photoshop is written in Pascal/ASM 1st release of souce has been submitted to the technical history museum, and paintshop pro is written still written in Python,TCL and ASM ... a common denominator of these to "Fast and Great image processors is ASM, although photoshop may have Upgraded to delphi now it is still pascal. and any speed problems are comming from pascal but this is because we like the way programs look and not what they do now days. I would like to make a Photoshop Clone in pure ASM which I have been working on and its comming along rather well. not code,interpret,arange,rewwrite,etc.... Just code and go process complete.
