Intel C/C++ Compiler 8.0 Released

Peorth writes "Intel has released version 8.0 of their Intel C/C++ compiler for both Windows and Linux. This release has been rumored for a long time to contain 100% GCC source and binary compatibility. It seems great strides have been made in advancement of that goal, as well as of its performance, but it may have a long way to go yet. Has anyone had experiences with it yet, either good or bad?"

Comments

Re:Linux is their benchmark then

[njchick]

The Linux kernel specifically requires gcc because it uses gcc extensions. But it should be possible to recompile the usermode code with the Intel's compiler. Even glibc may be worth trying (if you bought the compiler).

The really interesting part is that the Intel's compiler supports Itanium. It's very hard to optimize for Itanium because of its very long instruction codes. Those who run CPU-intensive tasks on Itanium may be interested in the Intel's compiler.

Re:Linux is their benchmark then

[RML]

The Linux kernel specifically requires gcc because it uses gcc extensions. But it should be possible to recompile the usermode code with the Intel's compiler. Even glibc may be worth trying (if you bought the compiler).

The Intel compiler has supported compiling the kernel with it for a few versions now, I believe. It may require a few kernel patches, but I think some of them have been accepted into the kernel tree. Intel has a web page about it.

Re:Linux is their benchmark then

[larry bagina]

I see no other reason to make the compiler binary-compatible with GCC.

Actually, the gcc 3.0 series was changed to use Intel's C++ ABI, so gcc did the changing, not icc. Of course, icc did add support for some of gcc's extensions.

processor dispatch

[DAldredge]

Processor dispatch allows the compiler to generate multiple optimized code paths and dynamicaly select which optimized version of the routine to use based on the processor that the program is running on. This allows a single executiple to run with SSE/SSE2 support on the P4 and still run on processors that do not support SSE/SS2.

I do not know what happens when the app is ran on AMD processors that support SSE/SSE2.

Definitely going to try out this one

[sperling]

We've tested Intel's c++ compiler for linux at work, and it's cut the full distributed rebuild time of our gameserver software from about 9 mins to 3 mins. That alone is more than enough reason to switch IMO.
Performance-wise, it seems to have a slight edge over gcc, but this is subjective as I haven't really measured anything yet. Apart from the performance issues, I've found icc to be way more informative in its warnings and remarks than gcc. Unless you strictly believe in the GPL or are open-source only, I see no reason not to at least give it a try, it's a damned good piece of software.

Re:Real Timings

[RML]

Since this is Slashdot, this will quickly turn into a stupid bashing of Intel in favor of gcc, since everyone likes Free stuff and hates corporations.

"Free stuff" and "corporations" are not mutually exclusive. Most of the work done on gcc is by people who are paid to work on it.

And everyone will talk out of their asses about how the Intel compilers couldn't possibly be faster than gcc.

There are still many interesting optimizations that gcc doesn't implement. A lot of work is being done on adding them to the tree-ssa branch, which hopefully will be merged into mainline gcc for 3.5.

So, I figured I'd throw out some real numbers:

It sounds like you're doing floating-point intensive number crunching code, which quite honestly is where icc should give the greatest benefit over gcc. On integer workloads they should be much closer. Number crunching gets a big boost from vectorization, and icc does automatic vectorization. GCC doesn't (though work is underway), and it won't use vector instructions at all unless you supply -mmmx, -msse, -msse2, and/or an -march option that specifies an appropriate CPU type. You can still get the advantage of vectorization if you're willing to code it explicitly.