From mboxrd@z Thu Jan 1 00:00:00 1970 From: Joe Buck To: dje@watson.ibm.com (David Edelsohn) Cc: jbuck@Synopsys.COM, law@cygnus.com, drepper@cygnus.com, egcs@cygnus.com Subject: Re: mutex in frame code Date: Sun, 31 Jan 1999 23:58:00 -0000 Message-ID: <199901261842.KAA05151@atrus.synopsys.com> References: <9901261827.AA41042@marc.watson.ibm.com> X-SW-Source: 1999-01n/msg01008.html Message-ID: <19990131235800.BqCaskicekzW784PVk5t2F4BH9jgKu3Vu5tY9BmZ870@z> > 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.