Vault 7: Projects
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MPLAB
®
XC16 C Compiler Users Guide
DS50002071C-page 98 2012-2013 Microchip Technology Inc.
Options of the form -fflag specify machine-independent flags. Most flags have both
positive and negative forms; the negative form of -ffoo would be -fno-foo. In the
table below, only one of the forms is listed (the one that is not the default.)
TABLE 5-13: MACHINE-INDEPENDENT OPTIMIZATION OPTIONS
Option Definition
-finline-functions Integrate all simple functions into their callers. The compiler
heuristically decides which functions are simple enough to
be worth integrating in this way. If all calls to a given func-
tion are integrated, and the function is declared static,
then the function is normally not output as assembler code
in its own right.
-finline-limit=n By default, the compiler limits the size of functions that can
be inlined. This flag allows the control of this limit for func-
tions that are explicitly marked as inline (i.e., marked with
the inline keyword). n is the size of functions that can be
inlined in number of pseudo instructions (not counting
parameter handling). The default value of n is 10000.
Increasing this value can result in more inlined code at the
cost of compilation time and memory consumption.
Decreasing usually makes the compilation faster and less
code will be inlined (which presumably means slower
programs). This option is particularly useful for programs
that use inlining.
Note: Pseudo instruction represents, in this particular con-
text, an abstract measurement of functions size. In no way
does it represent a count of assembly instructions and as
such, its exact meaning might change from one release of
the compiler to an another.
-fkeep-inline-functions Even if all calls to a given function are integrated, and the
function is declared static, output a separate run time
callable version of the function. This switch does not affect
extern inline functions.
-fkeep-static-consts Emit variables declared static const when optimization isnt
turned on, even if the variables arent referenced.
The compiler enables this option by default. If you want to
force the compiler to check if the variable was referenced,
regardless of whether or not optimization is turned on, use
the -fno-keep-static-consts option.
-fno-function-cse Do not put function addresses in registers; make each
instruction that calls a constant function contain the
functions address explicitly.
This option results in less efficient code, but some strange
hacks that alter the assembler output may be confused by
the optimizations performed when this option is not used.
-fno-inline Do not pay attention to the inline keyword. Normally this
option is used to keep the compiler from expanding any
functions inline. If optimization is not enabled, no functions
can be expanded inline.
-fomit-frame-pointer Do not keep the Frame Pointer in a register for functions
that dont need one. This avoids the instructions to save, set
up and restore Frame Pointers; it also makes an extra reg-
ister available in many functions.
-foptimize-sib-
ling-calls
Optimize sibling and tail recursive calls.
Protego_Release_01_05-Related-OEM-Documentation-MPLAB-XC16-C-Compiler.pdf