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Re: Thoughts on LLVM and LTO
Daniel Berlin <dberlin@dberlin.org> writes:
| On Tue, 2005-11-22 at 19:25 +0100, Gabriel Dos Reis wrote:
| > Benjamin Kosnik <bkoz@redhat.com> writes:
| >
| > [...]
| >
| > | I'd actually like to make this a requirement, regardless of the option
| > | chosen.
| >
| > Amen.
| >
|
| Uh, IPA of any sort is generally not about speed.
| It's fine to say compile time performance of the middle end portions ew
| may replace should be same or better, but algorithms that operate on
| large portions of the program are over never fast, because they aren't
| linear.
| They usually take *at least* seconds per pass.
|
| So you need to quantify "good".
As I undestand it, we are going to merge information from different
translation units for the purpose of link-time optimization. I expect
some increase in compile-time there. I don't care that the algorithms
are linear or not. What I do care about is that for the end-result,
compile-time performance is kept in reasonable bounds -- no matter what
implementation technology is finally decided on.
-- Gaby