Re: Faster compilation speed

[dewar at gnat dot com (Robert Dewar)]

>>Why not make incremental compilation a standard for gcc...

I seriously doubt that incremental compilation can help. Usually it is far
better to aim at the simplest fastest possible compilation path without
bothering with the extra bookkeeping needed for IC.

Historically the fastest compilers have not been incremental, and IC has
only been used to make painfully slow compilers a little less painful

(I realize that some would put GCC into the second category here, but I 
would prefer that we keep efforts focussed on moving it into the first
category).

That being said, I still wonder over time whether the effort to speed up
gcc is effort well spent. Or rather, put that another way, let's try to make
sure that it is effort well spent. If there are obvious opportunities, then
certainly it makes sense to take advantage of them.

But there are definite effort tradeoffs, and continued increase in speed of
machines does tend to mute the requirements for faster compilation.

When Realia COBOL ran 10,000 lpm on a PC-1, with the major competitor running
at 1,000 lpm, then the speed difference was a major marketing advantage, but
now days with essentially the same compiler running over a million lines a
minute, and essentially the same competitive compiler running at 100,000 lpm
the difference is no longer nearly so significant :-)