[MacPorts] #9053: BUG gmp: crash in config.guess due to mfpvr instruction

[MacPorts]

#9053: BUG gmp: crash in config.guess due to mfpvr instruction
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  Reporter:  vincent-opdarw@…           |       Owner:  gwright@…           
      Type:  defect                     |      Status:  assigned            
  Priority:  Low                        |   Milestone:  Port Bugs           
 Component:  ports                      |     Version:  1.0                 
Resolution:                             |    Keywords:                      
      Port:  gmp                        |  
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Comment(by vinc17@…):

 Replying to [comment:20 mcalhoun@…]:
 > -force_cpusubtype_ALL is required on PPC architectures or else gmp won't
 work properly.

 What is the cause? (I think it may be related to broken CPU subtype
 detection.)

 > ABI=32 is required or else gmp will try to build a 64-bit library.

 Yes, this is what I'm saying: MacPorts fixes a bad choice from GMP. And I
 think it should do something similar concerning CPU subtype detection.

 > I do not see why -mpcu would necessarily be a problem or why disabling
 the CPU subtype detection would be a good thing.

 Why? The gcc man page says:
 {{{
        The subtype of the file created (like ppc7400 or ppc970 or i686) is
        determined by the flags that specify the ISA that GCC is
 targetting,
        like -mcpu or -march.  The -force_cpusubtype_ALL option can be used
 to
        override this.
 }}}
 So, avoiding CPU subtype detection and -mcpu in the first place would
 avoid the use of -force_cpusubtype_ALL (which may be buggy here since it
 does not control the correctness of assembly code, which GMP uses).

 > Just to help me understand, are we still talking about the crash in
 config.guess?

 Not directly, but a fix to the above problem can avoid the crash as a side
 effect.

-- 
Ticket URL: <http://trac.macports.org/ticket/9053#comment:21>
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