https://gcc.gnu.org/bugzilla/show_bug.cgi?id=116708
Bug ID: 116708
Summary: Documentation for -msse4 and -mno-sse4
Product: gcc
Version: unknown
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: other
Assignee: unassigned at gcc dot gnu.org
Reporter: alex.orange at utah dot edu
Target Milestone: ---
Background: I have a Intel(R) Xeon(R) CPU E5420 @ 2.50GHz which has SSE4.1 but
not SSE4.2 or SSE4a. I have used resolve-march-native (which I understand is
unaffiliated) to try to get a set of flags to mimic -march=native for building
on another machine. This spit out the -msse4 flag which sent me down a long
path.
>From the documentation I can't work out exactly what -msse4 does. From playing
around with things it appears that it is the equivalent of setting all the
-msse4* flags. Is -mno-sse4 the equivalent of using all the -mno-sse4* flags?
resolve-march-native is assuming that if a given flag is marked as disabled
that it should flip the no-ness of the flag and enable it. Running `gcc -Q
--help=target -march=native` show both -mno-sse4 and -msse4 as disabled, so I'm
trying to get some documentation about what these do so as to inform
resolve-march-native as to what it should do to work properly.
