uopt(5) uopt(5)
uopt - the ucode optimizer
The U-code optimizer, uopt, is a part of the compiling system and is
always invoked from one of the normal commands, such as cc(1), f77(1), or
pc(1). These compilers and others are referred to as the driver below.
Ordinarily, only options mentioned on the driver man page or the IRIS-4D
Series Compiler Guide are of interest. However uopt has the following
options not recognized by the driver which can be applied with the flag
prefix -Wo,. For example, to prevent loop unrolling completely from cc,
use cc -Wo,-loopunroll,0. For driver programs other than cc, f77, and
pc, see the appropriate man page to see how to pass options to a
compiler pass.
While the following are available in this release, there is no guarantee
that these will have the same names or even be available or in future
releases.
-loopunroll count
Each loop which uopt can unroll is unrolled count times. Set count
to 0 to prevent loop unrolling. One might wish to prevent loop
unrolling where one discovered through testing that unrolled loops
were slower (possibly due to cache effects) or where code size
reduction was critical. Defaults to 4.
-unrolllimit limit
Each loop which uopt can unroll is unrolled a maximum of limit
times. Defaults to 160.
/usr/lib/uopt
cc(1), pc(1), f77(1), IRIS-4D Series Compiler Guide
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