other/10301: Side effects of architecture specific flags are not documented.

[garen at garen dot net]

>Number:         10301
>Category:       other
>Synopsis:       Side effects of architecture specific flags are not documented.
>Confidential:   no
>Severity:       serious
>Priority:       medium
>Responsible:    unassigned
>State:          open
>Class:          doc-bug
>Submitter-Id:   net
>Arrival-Date:   Thu Apr 03 02:36:00 UTC 2003
>Closed-Date:
>Last-Modified:
>Originator:     garen at garen dot net
>Release:        All
>Organization:
>Environment:

>Description:
Looking in the gcc archives, I noticed a post that sums up the problem fairly well:

http://gcc.gnu.org/ml/gcc/2002-12/msg00235.html

There is a lot of confusion about what is implied by the -march settings.  Over in Gentoo land, there are several long running forum threads with hundreds of posts of people asking about what flags they ought to use: 

http://forums.gentoo.org/viewtopic.php?t=43648


Also, wrong code-gen bugs related to SSE2 insns are so widespread I kind of wonder why they aren't disabled, documentad as an experimental feature, or generate some kind of warning when used.

It would be very helpful if these sort of things were documented.  I'd think they'd go in the "Intel 386 and AMD x86-64 Options" section of the manual (http://gcc.gnu.org/onlinedocs/gcc-3.2.2/gcc/i386-and-x86-64-Options.html#i386%20and%20x86-64%20Options)


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