ICC vs GCC - Optimization and CPU architecture

gcc x86 compiler-construction 64-bit icc
Rayne picture Rayne · Mar 23, 2010 · Viewed 9.1k times · Source

I'm interested in knowing how GCC differs from Intel's ICC in terms of the optimization levels and catering to specific processor architecture. I'm using GCC 4.1.2 20070626 and ICC v11.1 for Linux.

How does ICC's optimization levels (O1 to O3) differ from GCC, if they differ at all?

The ICC is able to cater specifically to different architectures (IA-32, intel64 and IA-64). I've read that GCC has the -march compiler option which I think is similar, but I can't find a list of the options to use. I'm using Intel Xeon X5570, which is 64-bit. Are there any other GCC compiler options I could use that would cater my applications for 64-bit Intel CPUs?

Answer

caf picture caf · Mar 23, 2010

See section 3.17.15 in the GCC manual, ie386 and x86-64 Options for the full list and description of all the options applicable to those architectures (IA-64 is Itanium, and it's unlikely you have one of those).

The most important options in this context are:

  • -m64 Generate 64-bit code;
  • -march= Generate instructions for a specific CPU type; and
  • -mtune= Tune the code for a specific CPU type.

Related questions

How do you use gcc to generate assembly code in Intel syntax?

The gcc -S option will generate assembly code in AT&T syntax, is there a way to generate files in Intel syntax? Or is there a way to convert between the two?

Read More
/usr/bin/ld: skipping incompatible foo.so when searching for foo

I am using Ubuntu 13.10 64bit and I am getting the following errors while compiling the python wrappers of vlfeat library. g++ -o _vlfeat.so ../../vl/aib.o ../../vl/generic.o ../../vl/hikmeans.o ../../vl/ikmeans.o ../../vl/imopv.o ../../vl/…

Read More
Can I use Intel syntax of x86 assembly with GCC?

I want to write a small low level program. For some parts of it I will need to use assembly language, but the rest of the code will be written on C/C++. So, if I will use GCC to …

Read More