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Re: abysmal code generated by gcc 3.2
- From: Mike Stump <mrs at apple dot com>
- To: Denys Duchier <Denys dot Duchier at ps dot uni-sb dot de>
- Cc: gcc at gcc dot gnu dot org
- Date: Mon, 21 Oct 2002 11:01:47 -0700
- Subject: Re: abysmal code generated by gcc 3.2
On Sunday, October 20, 2002, at 03:02 PM, Denys Duchier wrote:
I am at my wits ends. Can anyone help?
Well, if all else fails, you can build compilers from the cvs tree, and
binary search for when code generation changed from good to bad for
you. cvs co -D '300 days ago' gcc and then see if that compiler is as
bad. If it is not, cvs co -D '150 days ago' and try that one... If
you're lucky, in about 8 checkouts and rebuilds you should have it down
to the day the codegen died for you.
I'd do this only after experimenting with the top of the tree (to
ensure performance hasn't already returned for you), and experimenting
with all the relevant compiler flags, for example, see the following
parameters: max-inline-insns-single, max-inline-insns,
max-inline-slope, and min-inline-insns.