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Date: Tue, 01 Sep 2015 18:49:25 +0300
From: "Eli Zaretskii (eliz AT gnu DOT org) [via djgpp AT delorie DOT com]" <djgpp AT delorie DOT com>
Subject: Re: different binary output with 32- and 64-bit hosted compilers
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> Date: Tue, 1 Sep 2015 18:20:56 +0300
> From: "Ozkan Sezer (sezeroz AT gmail DOT com) [via djgpp AT delorie DOT com]" <djgpp AT delorie DOT com>
> 
> 32-bit (i686-linux fedora-9) and 64-bit (x86_64-linux fedora-20) hosted
> djgpp-targeting compiler generates different output for some sources.
> This happens with djgpp source itself too, and it isn't a nice thing
> and was not an expected thing for me. Did the following with gcc-3.4.6:
> 
> Compiled djgpp-cvs with a 32- and 64-bit hosted toolchain (gcc-3.4.6
> and binutils-2.25.1), then did:
> diff -urp --exclude=*.d --exclude=id_*.o --exclude=stub* \
>    --exclude=*.tex --exclude=*.exe --exclude=djasm.c \
>   32/src 64/src > 64.diff
> ... which results in this:

Looks like sign extension and register allocation differences.

GCC 3.4.6 is quite old, could well be a compiler bug.  Maybe it's a
good idea to repeat this experiment with a newer version, like 4.9.x?

Thanks.