For options that can be used as -foo or -foo=level we have a variety of different styels for documenting what the default level is. See below for several examples. I find this a bit confusing when try to see what it means to use the option without a level.
Do we want to pick a style and try to be consistent? For -Wformat-overflow we show the option with and without the level: @item -Wformat-overflow @itemx -Wformat-overflow=1 @opindex Wformat-overflow @opindex Wno-format-overflow Level @var{1} of @option{-Wformat-overflow} enabled by @option{-Wformat} For -Wshift-overflow we use prose to say what omitting the level means: @item -Wshift-overflow=1 This is the warning level of @option{-Wshift-overflow} and is enabled by default in C99 and C++11 modes (and newer). Similarly for -Wunused-const-variable: @item -Wunused-const-variable=1 This is the warning level that is enabled by @option{-Wunused-variable} for C. For -Wstrict-aliasing we add it to the sub-heading for the description of the corresponding level: Level 3 (default for @option{-Wstrict-aliasing}): For -Wstrict-overflow we add a sentence to the end of the paragraph about the corresponding level: @item -Wstrict-overflow=2 Also warn about other cases where a comparison is simplified to a constant. For example: @code{abs (x) >= 0}. This can only be simplified when signed integer overflow is undefined, because @code{abs (INT_MIN)} overflows to @code{INT_MIN}, which is less than zero. @option{-Wstrict-overflow} (with no level) is the same as @option{-Wstrict-overflow=2}. For -Warray-bounds we list both options separately, and then also list the forms with levels and say what no level means: @item -Warray-bounds @itemx -Warray-bounds=@var{n} @opindex Wno-array-bounds @opindex Warray-bounds This option is only active when @option{-ftree-vrp} is active (default for @option{-O2} and above). It warns about subscripts to arrays that are always out of bounds. This warning is enabled by @option{-Wall}. @table @gcctabopt @item -Warray-bounds=1 This is the warning level of @option{-Warray-bounds} and is enabled by @option{-Wall}; higher levels are not, and must be explicitly requested. For -Wattribute-alias and -Wplacement-new we do the same as -Warray-bounds. For -Wnormalized we use prose: There are four levels of warning supported by GCC@. The default is @option{-Wnormalized=nfc}, which warns about any identifier that is For -g we say: @item -g@var{level} @itemx -ggdb@var{level} @itemx -gstabs@var{level} @itemx -gxcoff@var{level} @itemx -gvms@var{level} Request debugging information and also use @var{level} to specify how much information. The default level is 2. For -flive-patching we add a paragraph at the end: When @option{-flive-patching} is specified without any value, the default value is "inline-clone".