Hi Jeff,
On 05.01.2016 19:21, Jeff Law wrote:
> On 01/05/2016 06:20 AM, Bernd Edlinger wrote:
>> Hi,
>>
>> On 05.01.2016 13:58, Bernd Schmidt wrote:
>>> On 01/05/2016 09:44 AM, Bernd Edlinger wrote:
>>>> an in-tree mpfr build enables inline asm code, which makes the
>>>> mips-bootstrap fail,
>>>> because at least mpfr 2.4.2 uses the "=h" constraint but in
>>>> config/mips/constraints.md
>>>> we find: "Formerly the @code{hi} register. This constraint is no
>>>> longer supported.".
>>>>
>>>> Using asm code is generally not desirable for in-tree mpfr builds.
>>>
>>> Why not?
>>
>> for the same reason why we disable the asm code for in-tree gmp.
>>
>> If we think mpfr is fine to use assembler, why don't we let gmp use the
>> assember code too?
>>
>> When we boot-strap to a different architecture we certainly do not want
>> to fiddle with inline-assember bugs, unless absolutely necessary.
> Given that we're already building against the mpfr-3.x.y API/ABI for
> out-of-tree builds, what about just updating mpfr in the
> infrastructure directory? It's only the in-tree builds of mpfr that
> are suffering and they're using an ancient mpfr.
>
> I guess you'd have to verify that it works and that doing so doesn't
> require updating gmp and mpc. But stepping forward seems like the
> best solution to me.
>
> jeff
Maybe, that can of course improve things but...
I tried to update to gmp 6.0.0 a while ago, and I noticed that it won't
build unless we also update to latest mpfr and mpc at the same time.
But from Marc Glisse's comment:
"Note that, at least with recent versions, if you configure gmp with
--disable-assembly, the flag -DNO_ASM ends up in __GMP_CFLAGS (in gmp.h)
and mpfr thus uses it automatically.
Hmm, that probably doesn't apply here since gcc passes its own CC and
CFLAGS to mpfr, please ignore my message. "
I've learned, that it is the intention to mimic the --disable-assembly
setting from gmp in mpfr, but we break that mechanism, by overwriting
the CFLAGS
after configure modifies them. For me the in-tree configuration was
always like a convenience, that prefers safety over speed.
Bernd.
