Re: mutex in frame code

[Joe Buck <jbuck at Synopsys dot COM>]

> Joe> One possibility: add -march to the Sparc port, -mtune to the i386 port,
> Joe> insist that all ports that target processor families use -march or -mtune
> Joe> in the future, and deprecate -mcpu.  Leave it in for the time being.

David E. writes:

> 	Well, that does not make sense for all ports, for example rs6000.
> POWER and PowerPC have defined architectures that do not change from
> processor to processor.  One wants to specify a CPU to set both
> architecture and tuning parameters.  Saying -march=604 is incorrect and
> -march=powerpc is not specific enough.

Perhaps you're having a problem with the flag names, but the concepts are
applicable.  There's a common subset that will permit programs to run on
both POWER and PowerPC, right?  I might use -march=common to specify that.
The flag -march=powerpc would generate code that would run on any PowerPC,
but maybe not on POWER.

Generally one would not specify an exact processor in -march, but it would
make sense in -mtune.  -march says what instructions I can assume are
present (and possibly, what restrictions on instruction order for
processors without interlocks, what few that exist).  -mtune says what
I should optimize for.