增加优化级别g ++ [英] Increasing Optimization Level g++

问题描述

我试图使用cygwin和g ++编译一个相对简单的c ++程序。我可以使用以下命令编译它：

I'm trying to compile a relatively simple c++ program using cygwin and g++. I can compile it using the following command:

g ++ -o main main.cpp -lgmpxx -lgmp

（注意：最后两个反映了gmp库的包含）。

(note: the last two reflect the inclusion of the gmp libraries).

编译的优化级别。我想我可以只是改变这个命令行为：

I'd like to increase the level of optimization that this is compiled with. I thought that I could just change this command line to:

g ++ -o3 main main.cpp -lgmpxx -lgmp

但这完全炸了。我得到两个全屏的错误消息。

but this totally blows up. I get about two full screens of error messages.

如何提高优化？谢谢！

推荐答案

这应该是 -O3 ，而不是 -o3 。否则，你要告诉g ++将编译好的可执行文件放入一个名为 3 的文件中，然后喂它 main ，您之前编译的可执行文件，作为输入。它可能试图将其解释为源代码，因此错误。

That should be -O3, not -o3. Otherwise you're telling g++ to put the compiled executable into a file named 3, and you're feeding it main, your previously-compiled executable, as input. It's probably trying to interpret that as source code, hence the errors.

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