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This is very interesting. I know Intel has their own compilers, but wouldn't seconding a couple engineers to the GCC/LLVM teams yield exactly the benefit you'r

This is very interesting. I know Intel has their own compilers, but wouldn't seconding a couple engineers to the GCC/LLVM teams yield exactly the benefit you're describing here? It's a trivial cost to boost their own add-ons.

m000 6y ago
Intel's handling of ICC has always puzzled me. I'd bet Intel could live without any of the money it made them. Yet, they never open-sourced it so that GCC/LLVM could catch up faster with any tricks that gave ICC a performance edge. Knowing that Intel chips were fully supported by all major compilers would probably translate to more chip sale profits than the profits of selling ICC as a tool. The least they could have done was to release a stripped down version (e.g. without advanced profiling tools) as a no-nonsense free download.
- acdha 6y ago
  That would also have made it easy for a fork to remove the code which disabled optimizations on AMD processors. I suspect that their managers viewed this as an edge since they could post high benchmark scores even if most common software didn’t use icc.
  - martinpw 6y ago
    It's actually easy to work around the AMD deoptimization by just pretending to be an Intel CPU when the check is made - no need to fork the code. On the bigger point, it ends up hurting them because companies often use gcc to benchmark across systems, so the Intel performance comes out lower than it might be if Intel really invested heavily in gcc rather than icc.
    - acdha 6y ago
      Yes, you can bypass the check by editing the binary but that’s a non-trivial extra step and, more importantly, it means you can’t use the official binaries for anything. Far from insurmountable but it’s the kind of things sales guys are going to make sure every large customer‘s senior management hears.
- BooneJS 6y ago
  Right. Because AMD had the same instructions (but presumably different pipeline timings?), they kept their secrets behind a bit of a wall which added friction for people who would have liked extra performance but not been willing to jump through the hoops required to get it. So now Intel chips are limiting battery life because every application is executing unoptimized garbage that runs longer and therefore uses more energy. Meanwhile, Apple Xcode will produce optimized binaries for Apple Silicon and the press will go wild.

m000 6y ago

Intel's handling of ICC has always puzzled me. I'd bet Intel could live without any of the money it made them. Yet, they never open-sourced it so that GCC/LLVM could catch up faster with any tricks that gave ICC a performance edge. Knowing that Intel chips were fully supported by all major compilers would probably translate to more chip sale profits than the profits of selling ICC as a tool. The least they could have done was to release a stripped down version (e.g. without advanced profiling tools) as a no-nonsense free download.

acdha 6y ago
That would also have made it easy for a fork to remove the code which disabled optimizations on AMD processors. I suspect that their managers viewed this as an edge since they could post high benchmark scores even if most common software didn’t use icc.
- martinpw 6y ago
  It's actually easy to work around the AMD deoptimization by just pretending to be an Intel CPU when the check is made - no need to fork the code. On the bigger point, it ends up hurting them because companies often use gcc to benchmark across systems, so the Intel performance comes out lower than it might be if Intel really invested heavily in gcc rather than icc.
  - acdha 6y ago
    Yes, you can bypass the check by editing the binary but that’s a non-trivial extra step and, more importantly, it means you can’t use the official binaries for anything. Far from insurmountable but it’s the kind of things sales guys are going to make sure every large customer‘s senior management hears.
BooneJS 6y ago
Right. Because AMD had the same instructions (but presumably different pipeline timings?), they kept their secrets behind a bit of a wall which added friction for people who would have liked extra performance but not been willing to jump through the hoops required to get it. So now Intel chips are limiting battery life because every application is executing unoptimized garbage that runs longer and therefore uses more energy. Meanwhile, Apple Xcode will produce optimized binaries for Apple Silicon and the press will go wild.