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Re: [PATCH, ARM] ARM / linux float ABI discrepancy
- From: "Joseph S. Myers" <joseph at codesourcery dot com>
- To: Christophe Lyon <christophe dot lyon at st dot com>
- Cc: gcc-patches at gcc dot gnu dot org
- Date: Tue, 7 Sep 2010 13:28:02 +0000 (UTC)
- Subject: Re: [PATCH, ARM] ARM / linux float ABI discrepancy
- References: <4C863049.1050202@st.com>
On Tue, 7 Sep 2010, Christophe Lyon wrote:
> Hi,
>
> As I mentioned in http://gcc.gnu.org/ml/gcc/2010-08/msg00280.html, there is a
> discrepancy in the description of the default float ABI when it comes to
> multilib support for ARM/Linux.
>
> Without this patch, using
> MULTILIB_OPTIONS = msoft-float/mhard-float
>
> would have the effect of handling 2 lib sets both compiled as msoft-float.
>
> The small patch I propose is attached.
The floating-point ABI issue isn't as simple as your patch would suggest,
because the default can be controlled with the --with-float configure
option. In addition, there are the alternative -mfloat-abi=* spellings,
so you need either to add MULTILIB_MATCHES for those to work properly, or
to make -mhard-float and -msoft-float really be aliases for the canonical
-mfloat-abi= versions using the .opt alias machinery (and then adjust all
the t-* files using those options accordingly). (Once my multilib
selection changes are finished, it wouldn't actually be necessary to mark
the options as aliases to get the multilib selection working correctly.)
The endianness part may be the remaining bit of PR target/16350.
--
Joseph S. Myers
joseph@codesourcery.com