benchmarking with and without "register" storage class specifier

[Michael S. Zick]

On Wed March 29 2006 06:54, Robert P. J. Day wrote:
RP> 
RP>   i did several runs of:
RP> 
RP> 	$ make distclean defconfig
RP> 	$ time make busybox
RP> 
RP> both before and after applying my two earlier submitted patches that
RP> removed a majority of the "register" storage class specifiers, and the
RP> results are indistinguishable in terms of build time.
RP> 
Robert,

Those register storage class specifiers may be left-overs from the days
of gcc-2.9x  Those compilers had problems dealing with register pressure.

In that compiler, they had a much greater influence than they do in the
series 3 or series 4 gcc compilers.

Of course, it also depends on cpu.  If testing on x86, register pressure
will make the register storage class specification a waste.

Testing on machines with a larger set of registers should show a difference,
at least in the generated code.

May also make a difference with some vendor (non-gcc) compilers.

Mike