what 's the optimize option -O2 do?

[huachang]

What 's the optimize option -O2 do?

When i was using icpc to compile my project on linux with -g -O2. I found a segment fault error. While It works when I delete -O2. So how many detail options in  -O2 ? How can I fix my problem?

BTW, I used makecontext when I was generating fiber threads.

[SergeyKostrov]

>>...What 's the optimize option -O2 do? /O2 - optimize for maximum speed (DEFAULT) >>...So how many detail options in -O2?.. Please take a look at Intel C++ compiler User's and Reference Guide for a complete description of that option ( online or in pdf-format ) >>How can I fix my problem? >> >>BTW, I used makecontext when I was generating fiber threads... A reproducer is needed to help with understanding what is wrong.

[huachang]

Thanks Sergey Kostrov

I is hard to post my project as it is too large!

I've tested to add -fno-builtin option in a test project!  With this option, I got the same assemble code using gcc and icc in a test code. I will test it in my project. I will post further result if i get some error.

[huachang]

I fixed this problems by add -fno-builtin and -fno-inline 。THS