Red Hat ENTERPRISE LINUX 4 Manual page 76

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Disabled at level
-ffunction-sections
-fdata-sections
Place each function or data item into its own section in the output file if the target supports
arbitrary sections. The name of the function or the name of the data item determines the section's
name in the output file.
Use these options on systems where the linker can perform optimizations to improve locality of
reference in the instruction space.
Only use these options when there are significant benefits from doing so. When you specify these
options, the assembler and linker will create larger object and executable files and will also be
slower. You will not be able to use
have problems with debugging if you specify both this option and
-fbranch-target-load-optimize
Perform branch target register load optimization before prologue / epilogue threading. The use
of target registers can typically be exposed only during reload, thus hoisting loads out of loops
and doing inter-block scheduling needs a separate optimization pass.
-fbranch-target-load-optimize2
Perform branch target register load optimization after prologue / epilogue threading.
-param =
name value
In some places, GCC uses various constants to control the amount of optimization that is done.
For example, GCC will not inline functions that contain more that a certain number of instruc-
tions. You can control some of these constants on the command-line using the
The names of specific parameters, and the meaning of the values, are tied to the internals of the
compiler, and are subject to change without notice in future releases.
In each case, the
table:
max-crossjump-edges
The maximum number of incoming edges to consider for crossjumping. The algorithm used
by
-fcrossjumping
values mean more aggressive optimization, making the compile time increase with probably
small improvement in executable size.
max-delay-slot-insn-search
The maximum number of instructions to consider when looking for an instruction to fill a
delay slot. If more than this arbitrary number of instructions is searched, the time savings
from filling the delay slot will be minimal so stop searching. Increasing values mean more
aggressive optimization, making the compile time increase with probably small improve-
ment in executable run time.
max-delay-slot-live-search
When trying to fill delay slots, the maximum number of instructions to consider when
searching for a block with valid live register information. Increasing this arbitrarily cho-
sen value means more aggressive optimization, increasing the compile time. This parameter
should be removed when the delay slot code is rewritten to maintain the control-flow graph.
.
-Os
gprof
is an integer. The allowable choices for
value
is O(N^2) in the number of edges incoming to each block. Increasing
Chapter 4. GCC Command Options
on all systems if you specify this option and you may
.
-g
-param
are given in the following
name
option.