If your meaning for the word "performance" is the usual meaning, the
earlier response by Andrew Haley answers the whole question.
But the way you phrased the question makes me think you meant "behavior"
when you wrote "performance".
-fno-strict-aliasing can give you correct behavior from a program that
incorrectly uses a reinterpret_cast or similar operation. That should be
considered a bug, and if there are few of those in your code, you should
find and correct them.
Some old code has enough incorrect reinterpret_cast operations that
correcting them is impractical and you need the -fno-strict-aliasing
I'm not sure what -DNDEBUG or -static might change in the behavior or
performance of your code. I'm just guessing that -fno-strict-aliasing is
the important difference.
Wei, Wanxia wrote:
gcc -m32 -O3 -DNDEBUG -fno-strict-aliasing -static –lm
gcc -m32 –O3 –lm
...
the
different performance of the two executables of my C program means there are bugs in
this program?
