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Message
From: Matjaz Breskvar<phoenix@o...>
Date: Wed Dec 17 23:23:41 CET 2003
Subject: [openrisc] or32-gcc: Current status + new version
Great work!I'm going to try your patches on uClinux & linux and if it builds them i'm
all for merging it into opencores mainline. The binary size savings are
nice too.
I'd like to caution you about -msoft-mul. I've only briefly checked
it after i've implemented it but i didn't do any extensive testing. It
*should* work ok, but don't count on it. ;)
The toolchain issue reamaining i know of is ld with -r flag. I tried the
Scott patches but the linker then just core dumped. I didn't have time
to really look into it... I'll fix this as soon as i have some
time since many bugs i saw that *look* like gcc are actually because
of linker.
i'm also interested why you say that opencores gcc with -O2 is
buggy. i tried building linux & uclinux with it and it worked just as good
as with -O flag. can you provide some more details...
best regards,
p.
* Heiko Panther (heiko.panther@w...) wrote:
> Hi folks,
>
> there has been some confusion about the various gcc compilers and their
> respective bugs or features. I did some research and a lot of
> experimenting, and here's my summary.
>
> Testing objectives
>
> - I tested if the optimization (-O2) works by running eCos, which has in
> the past produced errors in printf()-like routines when the compiler had
> -O2 enabled.
> - I checked if the gcc could build newlib (important for the folks who
> don't run eCos or other OSes which include a libc). To achieve this, I
> created symbolic links for newlib and libgloss from the newlib dir into
> the gcc dir, and used the gcc --with-newlib configure option.
> - Since it's important for me, I checked for availability of the
> -msoft-mul flag.
> - Lastly, I compiled my app, which includes eCos and a user application,
> and noted down the binary size, compiled with -O2. Compilers that
> produce buggy code with -O2 weren't checked.
>
> Test results
>
> opencores(oc) gcc-3.2.3
> -O2 buggy. Builds newlib. Has -msoft-mul.
>
> oc-gcc-3.2.3 Scott Furman version
> Scott sent me his modification, which includes an ABI change. This means
> you have to recompile everything, including libs, for use with this.
> Scott says this modified ABI is faster, too.
> When I built my app with this, it wouldn't come up - eCos died while
> doing the static constructors. Didn't yet check why that happened.
> Builds newlib. Has -msoft-mul. Binary size: 420k.
>
> University Cantabria (uc) gcc-3.4
> Is built with a developmental version of gcc-3.4, which is probably the
> reason for not building newlib and the large binary size.
> Fixes the -O2 bug without changing the ABI. Can't build newlib. Doesn't
> have -msoft-mul. Binary size: 470k.
>
>
> New version
>
> Based on this, I decided to put a new gcc together, taking the target
> config from uc-gcc-3.4 and putting it into oc-gcc-3.2.3. I added the
> -msoft-mul support from oc-gcc-3.2.3. No ABI change. newlib has to be
> installed seperately (cd to newlib subdir of gcc build dir and make
> install).
> -O2 working. Builds newlib. Has -msoft-mul. Binary size: 385k.
>
> So, with this, we should have a reliably working and optimizing
> compiler. The files and instructions are at
> http://homepage.mac.com/hpanther/gcc-3.2.3-oc-to-uc-patch.tgz
>
> I invite you to try and build you apps and OSes with this version. If
> everyone is satisfied (or no one complains, whichever happens first), I
> shall put the files into CVS (given that I'm granted CVS write access,
> wink wink. Otherwise, maybe one of the opencores maintainers will do that).
>
> Heiko
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