[blfs-support] porting LFS/BLFS to another machine

Dr.-Ing. Edgar Alwers edgaralwers at gmx.de
Fri Mar 4 07:30:56 PST 2016


For the records. Was: Internal compiler error ?

Porting a LFS/BLFS system built on a machine 1 to a machine 2 may result in a 
ported-system in 2 with a failing compiler. This seems to be due to a 
malfunctioning instruction MULX ( unsigned multiplication ) in the gmp 
procedure.

See Michael Shell contribution: 

https://www.mail-archive.com/blfs-support@lists.linuxfromscratch.org/msg02228.html

The correction was given for gmp-6.0.0a, the problem persists however in the 
actual gmp-6.1.0 of LFS.

As Michael Shell indicated, the problem can be fixed by replacing the code 
following the line 846 in config.guess:

	if (strcmp (modelstr, "haswell") == 0)
          {
            /* Some Haswells lack BMI2.  Let them appear as Sandybridges for
               now.  */
            CPUID (feature_string, 7);
            if ((feature_string[0 + 8 / 8] & (1 << (8 % 8))) == 0)
            modelstr = "sandybridge";
         }
by
        modelstr = "coreisbr";

and deleting in mpn/x86_64/fat/fat.c the line 314/315:

	if ((dummy_string[0 + 8 / 8] & (1 << (8 % 8))) != 0)
                CPUVEC_SETUP_coreihwl;

A general solution seems to be still pending

Edgar

-- 
Dr.-Ing. Edgar Alwers <edgaralwers at gmx.de>
GPG Key ID:AD5C6F70


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