The description of -march=i686/pentiumpro in the gcc manpage is:
i586, pentium
Intel Pentium CPU with no MMX support.
pentium-mmx
Intel PentiumMMX CPU based on Pentium core with MMX instruction set support.
pentiumpro
Intel PentiumPro CPU.
i686
Same as "generic", but when used as "march" option, PentiumPro instruction
set will be used, so the code will run on all i686 family chips.
In this context it is not clear whether i686 includes MMX support or not.
Checking Wikipedia suggests (though it is not clearly mentioned) that the
PentiumPro contained no MMX support, which arrived only with the Pentium II.
Thus the description of "pentiumpro" should probably include "with no MMX
support" as the description of "pentium" does.
--
Summary: gcc manpage: Description of x86 -march not clear
regarding mmx
Product: gcc
Version: 4.4.2
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: other
AssignedTo: unassigned at gcc dot gnu dot org
ReportedBy: devurandom at gmx dot net
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=42683
