-.\" Automatically generated by Pod::Man version 1.1
-.\" Fri Mar 9 21:54:51 2001
+.\" Automatically generated by Pod::Man version 1.15
+.\" Wed Apr 25 21:39:15 2001
.\"
.\" Standard preamble:
.\" ======================================================================
.\" ======================================================================
.\"
.IX Title "GCC 1"
-.TH GCC 1 "gcc-3.1" "2001-03-09" "GNU"
+.TH GCC 1 "gcc-3.1" "2001-04-25" "GNU"
.UC
.SH "NAME"
gcc \- \s-1GNU\s0 project C and \*(C+ compiler
\&\-Werror-implicit-function-declaration
\&\-Wimport \-Winline
\&\-Wlarger-than-\fR\fIlen\fR \fB\-Wlong-long
-\&\-Wmain \-Wmissing-declarations
+\&\-Wmain \-Wmissing-braces \-Wmissing-declarations
\&\-Wmissing-format-attribute \-Wmissing-noreturn
\&\-Wmultichar \-Wno-format-extra-args \-Wno-format-y2k
\&\-Wno-import \-Wpacked \-Wpadded
\&\-Wstrict-prototypes \-Wtraditional\fR
.Ip "\fIDebugging Options\fR" 4
.IX Item "Debugging Options"
-\&\fB\-a \-ax \-d\fR\fIletters\fR \fB\-fdump-unnumbered \-fdump-translation-unit=\fR\fIfile\fR
-\&\fB\-fdump-class-layout=\fR\fIfile\fR \fB\-fpretend-float \-fprofile-arcs \-ftest-coverage
+\&\fB\-a \-ax \-d\fR\fIletters\fR \fB\-dumpspecs \-dumpmachine \-dumpversion
+\&\-fdump-unnumbered \-fdump-translation-unit=\fR\fIfile\fR
+\&\fB\-fdump-class-layout=\fR\fIfile\fR \fB\-fmem-report \-fpretend-float
+\&\-fprofile-arcs \-ftest-coverage \-ftime-report
\&\-g \-g\fR\fIlevel\fR \fB\-gcoff \-gdwarf \-gdwarf-1 \-gdwarf-1+ \-gdwarf-2
\&\-ggdb \-gstabs \-gstabs+ \-gxcoff \-gxcoff+
\&\-p \-pg \-print-file-name=\fR\fIlibrary\fR \fB\-print-libgcc-file-name
\&\-fcse-follow-jumps \-fcse-skip-blocks \-fdata-sections \-fdce
\&\-fdelayed-branch \-fdelete-null-pointer-checks
\&\-fexpensive-optimizations \-ffast-math \-ffloat-store
-\&\-fforce-addr \-fforce-mem \-ffunction-sections \-fgcse
+\&\-fforce-addr \-fforce-mem \-ffunction-sections \-fgcse \-fgcse-lm \-fgcse-sm
\&\-finline-functions \-finline-limit=\fR\fIn\fR \fB\-fkeep-inline-functions
\&\-fkeep-static-consts \-fmove-all-movables
\&\-fno-default-inline \-fno-defer-pop
Warn if the type of \fBmain\fR is suspicious. \fBmain\fR should be a
function with external linkage, returning int, taking either zero
arguments, two, or three arguments of appropriate types.
+.Ip "\fB\-Wmissing-braces\fR" 4
+.IX Item "-Wmissing-braces"
+Warn if an aggregate or union initializer is not fully bracketed. In
+the following example, the initializer for \fBa\fR is not fully
+bracketed, but that for \fBb\fR is fully bracketed.
+.Sp
+.Vb 2
+\& int a[2][2] = { 0, 1, 2, 3 };
+\& int b[2][2] = { { 0, 1 }, { 2, 3 } };
+.Ve
.Ip "\fB\-Wmultichar\fR" 4
.IX Item "-Wmultichar"
Warn if a multicharacter constant (\fB'\s-1FOOF\s0'\fR) is used. Usually they
.Ip "\fB\-Wtraditional (C only)\fR" 4
.IX Item "-Wtraditional (C only)"
Warn about certain constructs that behave differently in traditional and
-\&\s-1ISO\s0 C.
+\&\s-1ISO\s0 C. Also warn about \s-1ISO\s0 C constructs that have no traditional C
+equivalent, and/or problematic constructs which should be avoided.
.RS 4
.Ip "\(bu" 4
Macro parameters that appear within string literals in the macro body.
constant suffixes. (Traditonal C does support the `L' suffix on integer
constants.) Note, these suffixes appear in macros defined in the system
headers of most modern systems, e.g. the _MIN/_MAX macros in limits.h.
-Use of these macros can lead to spurious warnings as they do not
-necessarily reflect whether the code in question is any less portable to
-traditional C given that suitable backup definitions are provided.
+Use of these macros in user code might normally lead to spurious
+warnings, however gcc's integrated preprocessor has enough context to
+avoid warning in these cases.
.Ip "\(bu" 4
A function declared external in one block and then used after the end of
the block.
user code appears conditioned on e.g. \f(CW\*(C`_\|_STDC_\|_\*(C'\fR to avoid missing
initializer warnings and relies on default initialization to zero in the
traditional C case.
+.Ip "\(bu" 4
+Conversions by prototypes between fixed/floating point values and vice
+versa. The absence of these prototypes when compiling with traditional
+C would cause serious problems. This is a subset of the possible
+conversion warnings, for the full set use \fB\-Wconversion\fR.
.RE
.RS 4
.RE
Warn if an undefined identifier is evaluated in an \fB#if\fR directive.
.Ip "\fB\-Wshadow\fR" 4
.IX Item "-Wshadow"
-Warn whenever a local variable shadows another local variable.
+Warn whenever a local variable shadows another local variable, parameter or
+global variable or whenever a built-in function is shadowed.
.Ip "\fB\-Wid-clash-\fR\fIlen\fR" 4
.IX Item "-Wid-clash-len"
Warn whenever two distinct identifiers match in the first \fIlen\fR
.IX Item "-Q"
Makes the compiler print out each function name as it is compiled, and
print some statistics about each pass when it finishes.
+.Ip "\fB\-ftime-report\fR" 4
+.IX Item "-ftime-report"
+Makes the compiler print some statistics about the time consumed by each
+pass when it finishes.
+.Ip "\fB\-fmem-report\fR" 4
+.IX Item "-fmem-report"
+Makes the compiler print some statistics about permanent memory
+allocation when it finishes.
.Ip "\fB\-ax\fR" 4
.IX Item "-ax"
Generate extra code to profile basic blocks. Your executable will
.Sp
Several function names have a special meaning:
.RS 4
-.if n .Ip "\f(CW""_\|_bb_jumps_\|_""\fR" 4
+.if n .Ip "\f(CW""""_\|_bb_jumps_\|_""""\fR" 4
.el .Ip "\f(CW_\|_bb_jumps_\|_\fR" 4
.IX Item "__bb_jumps__"
Write source, target and frequency of jumps to file \fIbb.out\fR.
-.if n .Ip "\f(CW""_\|_bb_hidecall_\|_""\fR" 4
+.if n .Ip "\f(CW""""_\|_bb_hidecall_\|_""""\fR" 4
.el .Ip "\f(CW_\|_bb_hidecall_\|_\fR" 4
.IX Item "__bb_hidecall__"
Exclude function calls from frequency count.
-.if n .Ip "\f(CW""_\|_bb_showret_\|_""\fR" 4
+.if n .Ip "\f(CW""""_\|_bb_showret_\|_""""\fR" 4
.el .Ip "\f(CW_\|_bb_showret_\|_\fR" 4
.IX Item "__bb_showret__"
Include function returns in frequency count.
-.if n .Ip "\f(CW""_\|_bb_trace_\|_""\fR" 4
+.if n .Ip "\f(CW""""_\|_bb_trace_\|_""""\fR" 4
.el .Ip "\f(CW_\|_bb_trace_\|_\fR" 4
.IX Item "__bb_trace__"
Write the sequence of basic blocks executed to file \fIbbtrace.gz\fR.
components where gcc expects to find them, or you can set the environment
variable \fB\s-1GCC_EXEC_PREFIX\s0\fR to the directory where you installed them.
Don't forget the trailing '/'.
+.Ip "\fB\-dumpmachine\fR" 4
+.IX Item "-dumpmachine"
+Print the compiler's target machine (for example,
+\&\fBi686\-pc-linux-gnu\fR)\-\-\-and don't do anything else.
+.Ip "\fB\-dumpversion\fR" 4
+.IX Item "-dumpversion"
+Print the compiler version (for example, \fB3.0\fR)\-\-\-and don't do
+anything else.
+.Ip "\fB\-dumpspecs\fR" 4
+.IX Item "-dumpspecs"
+Print the compiler's built-in specs\-\-\-and don't do anything else. (This
+is used when \s-1GCC\s0 itself is being built.)
.Sh "Options That Control Optimization"
.IX Subsection "Options That Control Optimization"
These options control various sorts of optimizations:
.Sp
This option causes the preprocessor macro _\|_FAST_MATH_\|_ to be defined.
.Sp
-This option causes the preprocessor macro _\|_FAST_MATH_\|_ to be defined.
-.Sp
This option should never be turned on by any \fB\-O\fR option since
it can result in incorrect output for programs which depend on
an exact implementation of \s-1IEEE\s0 or \s-1ISO\s0 rules/specifications for
.IX Item "-fgcse"
Perform a global common subexpression elimination pass.
This pass also performs global constant and copy propagation.
+.Ip "\fB\-fgcse-lm\fR" 4
+.IX Item "-fgcse-lm"
+When \-fgcse-lm is enabled, global common subexpression elimination will
+attempt to move loads which are only killed by stores into themselves. This
+allows a loop containing a load/store sequence to be changed to a load outside
+the loop, and a copy/store within the loop.
+.Ip "\fB\-fgcse-sm\fR" 4
+.IX Item "-fgcse-sm"
+When \-fgcse-sm is enabled, A store motion pass is run after global common
+subexpression elimination. This pass will attempt to move stores out of loops.
+When used in conjunction with \-fgcse-lm, loops containing a load/store sequence
+can be changed to a load before the loop and a store after the loop.
.Ip "\fB\-fdelete-null-pointer-checks\fR" 4
.IX Item "-fdelete-null-pointer-checks"
Use global dataflow analysis to identify and eliminate useless null
If an function contains more than this many instructions, it
will not be inlined. This option is precisely equivalent to
\&\fB\-finline-limit\fR.
+.Ip "\fBmax-gcse-memory\fR" 4
+.IX Item "max-gcse-memory"
+The approximate maximum amount of memory that will be allocated in
+order to perform the global common subexpression elimination
+optimization. If more memory than specified is required, the
+optimization will not be done.
.RE
.RS 4
.RE
-Werror-implicit-function-declaration @gol
-Wimport -Winline @gol
-Wlarger-than-@var{len} -Wlong-long @gol
--Wmain -Wmissing-declarations @gol
+-Wmain -Wmissing-braces -Wmissing-declarations @gol
-Wmissing-format-attribute -Wmissing-noreturn @gol
-Wmultichar -Wno-format-extra-args -Wno-format-y2k @gol
-Wno-import -Wpacked -Wpadded @gol
@item Debugging Options
@xref{Debugging Options,,Options for Debugging Your Program or GCC}.
@gccoptlist{
--a -ax -d@var{letters} -fdump-unnumbered -fdump-translation-unit=@var{file} @gol
--fdump-class-layout=@var{file} -fpretend-float -fprofile-arcs -ftest-coverage @gol
+-a -ax -d@var{letters} -dumpspecs -dumpmachine -dumpversion @gol
+-fdump-unnumbered -fdump-translation-unit=@var{file} @gol
+-fdump-class-layout=@var{file} -fmem-report -fpretend-float @gol
+-fprofile-arcs -ftest-coverage -ftime-report @gol
-g -g@var{level} -gcoff -gdwarf -gdwarf-1 -gdwarf-1+ -gdwarf-2 @gol
-ggdb -gstabs -gstabs+ -gxcoff -gxcoff+ @gol
-p -pg -print-file-name=@var{library} -print-libgcc-file-name @gol
function with external linkage, returning int, taking either zero
arguments, two, or three arguments of appropriate types.
+@item -Wmissing-braces
+Warn if an aggregate or union initializer is not fully bracketed. In
+the following example, the initializer for @samp{a} is not fully
+bracketed, but that for @samp{b} is fully bracketed.
+
+@smallexample
+int a[2][2] = @{ 0, 1, 2, 3 @};
+int b[2][2] = @{ @{ 0, 1 @}, @{ 2, 3 @} @};
+@end smallexample
+
@item -Wmultichar
Warn if a multicharacter constant (@samp{'FOOF'}) is used. Usually they
indicate a typo in the user's code, as they have implementation-defined
Makes the compiler print out each function name as it is compiled, and
print some statistics about each pass when it finishes.
+@item -ftime-report
+Makes the compiler print some statistics about the time consumed by each
+pass when it finishes.
+
+@item -fmem-report
+Makes the compiler print some statistics about permanent memory
+allocation when it finishes.
+
@item -ax
Generate extra code to profile basic blocks. Your executable will
produce output that is a superset of that produced when @samp{-a} is
variable @env{GCC_EXEC_PREFIX} to the directory where you installed them.
Don't forget the trailing '/'.
@xref{Environment Variables}.
+
+@item -dumpmachine
+Print the compiler's target machine (for example,
+@samp{i686-pc-linux-gnu})---and don't do anything else.
+
+@item -dumpversion
+Print the compiler version (for example, @samp{3.0})---and don't do
+anything else.
+
+@item -dumpspecs
+Print the compiler's built-in specs---and don't do anything else. (This
+is used when GCC itself is being built.) @xref{Spec Files}.
@end table
@node Optimize Options
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