[Bug target/78478] Compile Error for i386-rtems

[joseph at codesourcery dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=78478

--- Comment #5 from joseph at codesourcery dot com <joseph at codesourcery dot com> ---
On Tue, 22 Nov 2016, ubizjak at gmail dot com wrote:

> https://gcc.gnu.org/bugzilla/show_bug.cgi?id=78478
> 
> --- Comment #2 from Uroš Bizjak <ubizjak at gmail dot com> ---
> For 7.0, somebody changed i[34567]86-*-rtems* entry in libgcc/config.host to
> use t-softfp-sfdftf. Please test the following patch:

The change was by design meant to ensure that _Float128 was always 
available on x86, so that __float128 can always be aliased to _Float128.  
Making _Float128 always available means making libgcc support for TFmode 
always available.

I.e., the bug was enabling unintended soft-fp usage of XFmode at the same 
time as enabling usage of TFmode.  The TFmode functions should be kept in 
libgcc while disabling the conversions between XFmode and TFmode for this 
case.