In the past the "-ftree-loop-linear" switch provided a measurable
improvement in performance for certain functions. At some point it
was assigned as the responsibility of Graphite in GCC. It has been
found that even with Graphite enabled these flags no longer perform
any appreciable improvement over the baseline.
Graphite now has some open bugs which need to be fixed in order for it
to provide measurable performance improvements but it lacks active
development. As a result some compiler distributors may disable
Graphite. If Graphite is disabled then building GLIBC will fail if
the "-ftree-loop-linear" switch is used.
This patch removes the use of "-ftree-loop-linear" as unnecessary.
This patch provides optimized logb (1.2x on PPC32 and 2.5x on PPC64),
logbf (1.1x on PPC32 and 2.2x on PPC64), and logbl (1.3x on PPC32 and
50% on PPC64) for the POWER7 processor.
* sysdeps/powerpc/powerpc32/crti.S: New file.
* sysdeps/powerpc/powerpc32/crtn.S: New file.
* sysdeps/powerpc/powerpc64/crti.S: New file.
* sysdeps/powerpc/powerpc64/crtn.S: New file.
This patch tries to organize the implies files for ppc, since there are
a number of processors and most of them are compatible with each other
(backwards compatible).
Having in mind that we start the search for processor-specific files in
the sysdeps/unix/sysv/linux tree
(sysdeps/unix/sysv/linux/powerpc/powerpc[32|64]/[processor]/fpu to be
exact), we would like to grab any linux-specific code from that tree
prior to going through the other tree (sysdeps/powerpc/...).
For that, i removed the Implies files that were originally inside the
fpu directories and placed then in the non-fpu directories (still inside
the unix/sysv/linux tree). If no processor-specific/linux-specific files
could be found, we "imply" the other tree's (sysdeps/powerpc/...) fpu
directory for that specific processor AND also the non-fpu directory for
that same tree.
If, again, no processor-specific code is found, we read another Implies
file that will point to the most compatible processor that we should
grab code from, and so on, until we reach the power4 processor.
So, in summary, the Implies files will live inside these directories
now:
* sysdeps/unix/sysv/linux/powerpc/powerpc[32|64]/[processor]
* sysdeps/powerpc/powerpc[32|64]/[processor]
Practical example of the order we will use to pick power6-specific code
with the new structure.
sysdeps/unix/sysv/linux/powerpc/powerpc[32|64]/power6/fpu ->
sysdeps/unix/sysv/linux/powerpc/powerpc[32|64]/power6 ->
sysdeps/powerpc/powerpc[32|64]/power6/fpu ->
sysdeps/powerpc/powerpc[32|64]/power6 ->
sysdeps/powerpc/powerpc[32|64]/power5+/fpu ->
sysdeps/powerpc/powerpc[32|64]/power5+ ->
sysdeps/powerpc/powerpc[32|64]/power5/fpu ->
sysdeps/powerpc/powerpc[32|64]/power5 ->
sysdeps/powerpc/powerpc[32|64]/power4/fpu ->
sysdeps/powerpc/powerpc[32|64]/power4 (from here, it'll go to the
generic path as usual)
