Function specific optimization in GCC 4.4.3

In reference to my earlier question here, I found out a possilbe bug in GCC 4.4.3 when it did not support following pragmas in the source code for optimiza开发者_开发知识库tion (although it says 4.4.x onwards it does!)

#pragma GCC optimize ("O3")

__attribute__((optimize("O3")))

Tried both above options but both gave compile time errors in the compiler itself(See the error message snapshot posted in the link mentioned above)

Now are there any further options for me to enable different optimization levels for different functions in my C code?

From the online docs:

Numbers are assumed to be an optimization level. Strings that begin with O are assumed to be an optimization option, while other options are assumed to be used with a -f prefix.

So, if you want the equivalent of the command line -O3 you should probably use the just the number 3 instead of "O3".

I agree that this is a bug and should not generate an ICE, consider reporting it along with a small test case to the GCC guys.

Now are there any further options for me to enable different optimization levels for different functions in my C code?

Your remaining option is to place the functions in their own .c file and compile that .c file with the optimization flag you want.