Intel i960 User Manual page 64

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i960 Processor Compiler User's Guide
O2
O3
O4
O5
This level includes the
described above, and the following additional
optimizations:
,
fcopyprop fcondxform
,
jumps fcse-skip-blocks
,
optimizations frerun-cse-after-loop
,
fschedule-insns fschedule-insns2
,
fshadow-globals fstrength-reduce
The level enables strength-reduction,
O2
combination of more than one variable value into
a single register, copy propagation, tail-call
elimination, leaf-procedure optimization, and
instruction reordering (scheduling) to make use
of the particular i960 processor's pipeline and
superscalar capabilities.
This level includes the
described above, and the following additional
optimizations:
,
fcoerce fconstprop
,
fshadow-mem funroll-loops
This level includes the
described above, and the following additional
optimizations:
,
fcoalesce fmarry_mem
This setting specifies program-wide
optimization. Before using the
should read Chapter 4, Program-wide Analysis
and Optimization, and Chapter 6, gcdm Decision
Maker Option.
Note that the level is not accepted directly by
O5
the gcc960 driver. It is accepted only in the
argument of the
subst
or optimizations
O O1
,
fcse-follow-
,
fexpensive-
,
,
.
optimizations
O2
,
finline-functions
.
optimizations
O3
, .
fsplit_mem
option, you
O5
option.
gcdm
,