Re: Removing -Wunsuffixed-float-constants, -Wdouble-promotion, -Wformat-zero-length

[Jim Meyering]

Paul Eggert wrote:
> On 11/30/11 02:25, Jim Meyering wrote:
>> how about automating the extraction of the list of
>> warnings from gcc sources or from some web page
>
> Or perhaps extract it from the gcc executable
> itself?  Then you'd get all the warnings that the
> current GCC supports.

Hah!

I didn't know about --help=warnings.
That looks perfect.

For a quick and dirty comparison, I did this:
(using gcc 4.7.0 20111124)

diff -u \
  <(sed -n 's/^  *\(-[^ ]*\) .*/\1/p' /gnulib/m4/manywarnings.m4 |sort) \
  <(gcc --help=warnings|sed -n 's/^  \(-[^ ]*\) .*/\1/p' |sort)

which shows at least one false positive (i.e. -Wformat=2 vs -Wformat=)
and many new warnings:

--- /proc/self/fd/11    2011-11-30 12:07:49.747440364 +0100
+++ /proc/self/fd/12    2011-11-30 12:07:49.747440364 +0100
@@ -1,79 +1,173 @@
+--all-warnings
+--extra-warnings
 -W
 -Wabi
+-Waddress
 -Waggregate-return
+-Waliasing
+-Walign-commons
 -Wall
+-Wampersand
+-Warray-bounds
+-Warray-temporaries
+-Wassign-intercept
 -Wattributes
 -Wbad-function-cast
 -Wbuiltin-macro-redefined
 -Wc++-compat
+-Wc++0x-compat
+-Wc++11-compat
 -Wcast-align
 -Wcast-qual
+-Wchar-subscripts
+-Wcharacter-truncation
+-Wclobbered
+-Wcomment
+-Wcomments
 -Wconversion
+-Wconversion-extra
+-Wconversion-null
 -Wcoverage-mismatch
 -Wcpp
+-Wctor-dtor-privacy
 -Wdeclaration-after-statement
+-Wdelete-non-virtual-dtor
 -Wdeprecated
 -Wdeprecated-declarations
 -Wdisabled-optimization
 -Wdiv-by-zero
 -Wdouble-promotion
+-Weffc++
+-Wempty-body
 -Wendif-labels
+-Wenum-compare
+-Werror-implicit-function-declaration
 -Wextra
 -Wfloat-equal
+-Wformat
 -Wformat-contains-nul
 -Wformat-extra-args
 -Wformat-nonliteral
 -Wformat-security
 -Wformat-y2k
 -Wformat-zero-length
--Wformat=2
+-Wformat=
+-Wfree-nonheap-object
+-Wfunction-elimination
+-Wignored-qualifiers
+-Wimplicit
+-Wimplicit-function-declaration
+-Wimplicit-int
+-Wimplicit-interface
+-Wimplicit-procedure
 -Winit-self
 -Winline
+-Wint-to-pointer-cast
+-Wintrinsic-shadow
+-Wintrinsics-std
+-Winvalid-memory-model
+-Winvalid-offsetof
 -Winvalid-pch
+-Wjump-misses-init
+-Wlarger-than-
+-Wlarger-than=<number>
+-Wline-truncation
 -Wlogical-op
 -Wlong-long
+-Wmain
+-Wmaybe-uninitialized
+-Wmissing-braces
 -Wmissing-declarations
+-Wmissing-field-initializers
 -Wmissing-format-attribute
 -Wmissing-include-dirs
 -Wmissing-noreturn
+-Wmissing-parameter-type
 -Wmissing-prototypes
 -Wmudflap
 -Wmultichar
--Wmultichar
+-Wnarrowing
 -Wnested-externs
--Wnormalized=nfc
+-Wnoexcept
+-Wnon-template-friend
+-Wnon-virtual-dtor
+-Wnonnull
+-Wnormalized=<id|nfc|nfkc>
+-Wold-style-cast
+-Wold-style-declaration
 -Wold-style-definition
 -Woverflow
 -Woverlength-strings
+-Woverloaded-virtual
+-Woverride-init
 -Wpacked
 -Wpacked-bitfield-compat
 -Wpadded
+-Wparentheses
+-Wpmf-conversions
 -Wpointer-arith
+-Wpointer-sign
 -Wpointer-to-int-cast
 -Wpragmas
+-Wproperty-assign-default
+-Wprotocol
+-Wreal-q-constant
 -Wredundant-decls
+-Wreorder
+-Wreturn-type
+-Wselector
+-Wsequence-point
 -Wshadow
--Wsign-conversion
+-Wsign-compare
+-Wsign-promo
 -Wstack-protector
+-Wstack-usage=
 -Wstrict-aliasing
+-Wstrict-aliasing=
+-Wstrict-null-sentinel
 -Wstrict-overflow
+-Wstrict-overflow=
 -Wstrict-prototypes
+-Wstrict-selector-match
 -Wsuggest-attribute=const
 -Wsuggest-attribute=noreturn
 -Wsuggest-attribute=pure
+-Wsurprising
+-Wswitch
 -Wswitch-default
 -Wswitch-enum
 -Wsync-nand
+-Wsynth
 -Wsystem-headers
+-Wtabs
 -Wtraditional
 -Wtraditional-conversion
 -Wtrampolines
+-Wtrigraphs
+-Wtype-limits
+-Wundeclared-selector
 -Wundef
+-Wunderflow
+-Wuninitialized
 -Wunknown-pragmas
--Wunreachable-code
 -Wunsafe-loop-optimizations
+-Wunsuffixed-float-constants
 -Wunused
+-Wunused-but-set-parameter
+-Wunused-but-set-variable
+-Wunused-dummy-argument
+-Wunused-function
+-Wunused-label
+-Wunused-local-typedefs
 -Wunused-macros
+-Wunused-parameter
+-Wunused-result
+-Wunused-value
+-Wunused-variable
+-Wvariadic-macros
+-Wvector-operation-performance
 -Wvla
 -Wvolatile-register-var
 -Wwrite-strings
+-Wzero-as-null-pointer-constant
+-frequire-return-statement