Messages in this thread | | | Subject | Re: GCC3.0 Produce REALLY slower code! | Date | Tue, 26 Jun 2001 04:18:21 -0400 | From | Hacksaw <> |
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>Apart from questions of optimization, compiling the same code with two >different compilers is a very good way to find bugs, both in the code >and in the compilers.
I agree that this is a workable idea. On the other hand, I'd bet Linus would put that idea right up there with shipping a debugger in kernel.
If you need to use tricks like that to find bugs, you might not understand your code as well as you should.
The optimization angle is an important one. I'd like to see intel's optimizations tested against the kernel, *and then released in gcc*, or something specialized like pgcc. (Anyone know if pgcc ever compiled a good kernel that was notably faster?)
Overall, though, I'd bet such optimizations would give no more than a few percentage points of speed overall. The big gains are to be had by serious redesign like the cache change or the zero copy stuff.
When your design is mediocre, an optimizing compiler makes the the wrong idea faster.
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