Bug 311711

Summary:	gcc -march=native and distcc
Product:	Gentoo Linux	Reporter:	Gordon Pettey <petteyg359>
Component:	[OLD] Core system	Assignee:	Gentoo Linux bug wranglers <bug-wranglers>
Status:	RESOLVED INVALID
Severity:	enhancement	CC:	xarthisius
Priority:	High
Version:	unspecified
Hardware:	All
OS:	All
Whiteboard:
Package list:		Runtime testing required:	---

Description Gordon Pettey 2010-03-28 04:36:19 UTC

distcc doesn't work with -march=native if a remote system has a different CPU than the target, because the remote system will compile with native for it's own CPU. Google tells me that the following command may be used to return the options gcc uses when -march=native:

gcc -march=native -E -v - </dev/null 2>&1 | sed -n 's/.* -v - //p'

Perhaps the distcc ebuild could have an einfo added to it suggesting use of this command to put in CFLAGS options that may be used with distcc across systems with differing CPUs.

Comment 1 Kacper Kowalik (Xarthisius) (RETIRED) gentoo-dev

2010-03-28 10:17:01 UTC

Please read http://www.gentoo.org/doc/en/distcc.xml
It's explicitly stated there: "Don't use -march=native when compiling with distcc"
As for the einfo, this "one-liner" may be confusing for some users. It's far more beneficial to read 'man gcc' and pick proper march/mtune yourself.
Best regards,
Kacper Kowalik