Re: GCC3.0 Produce REALLY slower code!

From: Hacksaw (
Date: Tue Jun 26 2001 - 03:18:21 EST

>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

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This archive was generated by hypermail 2b29 : Sat Jun 30 2001 - 21:00:13 EST