Bug 538164

Summary:	app-portage/cpuinfo2cpuflags generates wrong flags here
Product:	Gentoo Linux	Reporter:	Helmut Jarausch <jarausch>
Component:	[OLD] Development	Assignee:	Gentoo Linux bug wranglers <bug-wranglers>
Status:	RESOLVED INVALID
Severity:	normal	CC:	jlec
Priority:	Normal
Version:	unspecified
Hardware:	All
OS:	Linux
Whiteboard:
Package list:		Runtime testing required:	---

Description Helmut Jarausch 2015-01-29 15:03:18 UTC

Hi,

the relevant parts of cat /proc/cpuinfo are 

flags		: fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat pse36 clflush mmx fxsr sse sse2 ht syscall nx mmxext fxsr_opt pdpe1gb rdtscp lm 3dnowext 3dnow constant_tsc rep_good nopl nonstop_tsc extd_apicid pni monitor cx16 popcnt lahf_lm cmp_legacy svm extapic cr8_legacy abm sse4a misalignsse 3dnowprefetch osvw ibs skinit wdt hw_pstate npt lbrv svm_lock nrip_save vmmcall

On that machine, cpuinfo2cpuflags generates
CPU_FLAGS_X86="3dnow 3dnowext mmx mmxext popcnt sse sse2 sse3 sse4a"

but my gcc-4.9.2 doesn't know about -m3dnowext and -mmmxext.
This causes any package which requires a C-compiler to fail if the
CPU_FLAGS_X86 line above is added to /etc/portage/make.conf

Comment 1 Justin Lecher (RETIRED) gentoo-dev

2015-01-29 15:28:11 UTC

Could you please show a broken build.log? CPU_FLAGS_X86 are for USE flags not for compiler flags.

Comment 2 Helmut Jarausch 2015-01-29 15:40:44 UTC

Sorry, I think I've added these to my CFLAGS, as well.
Reverting this, there is no build error any more.

Helmut