Future changes will treat some C front end warnings similar to -Wnarrowing.
gcc/ * doc/invoke.texi (Warning Options): Mention C diagnostics for -fpermissive. gcc/c-family/ * c.opt (fpermissive): Enable for C and ObjC. * c-opts.cc (c_common_post_options): Enable -fpermissive. --- v3: Handle -fpermissive in c_common_post_options, to get useful behavior for various -std=gnu99 -fpermissive -std=gnu89 permutations. gcc/c-family/c-opts.cc | 12 ++++++++++++ gcc/c-family/c.opt | 2 +- gcc/doc/invoke.texi | 8 ++++++-- 3 files changed, 19 insertions(+), 3 deletions(-) diff --git a/gcc/c-family/c-opts.cc b/gcc/c-family/c-opts.cc index a980912f7e1..23ea79ec802 100644 --- a/gcc/c-family/c-opts.cc +++ b/gcc/c-family/c-opts.cc @@ -854,6 +854,18 @@ c_common_post_options (const char **pfilename) && flag_unsafe_math_optimizations == 0) flag_fp_contract_mode = FP_CONTRACT_OFF; + /* C language modes before C99 enable -fpermissive by default, but + only if -pedantic-errors is not specified. Also treat + -fno-permissive as a subset of -pedantic-errors that does not + reject certain GNU extensions also present the defaults for later + language modes. */ + if (!c_dialect_cxx () && !flag_isoc99 && !global_dc->m_pedantic_errors + && !global_options_set.x_flag_permissive) + { + flag_permissive = 1; + global_dc->m_permissive = 1; + } + /* If we are compiling C, and we are outside of a standards mode, we can permit the new values from ISO/IEC TS 18661-3 for FLT_EVAL_METHOD. Otherwise, we must restrict the possible values to diff --git a/gcc/c-family/c.opt b/gcc/c-family/c.opt index 29d3d789a49..cc3a6610148 100644 --- a/gcc/c-family/c.opt +++ b/gcc/c-family/c.opt @@ -2112,7 +2112,7 @@ C ObjC C++ ObjC++ Look for and use PCH files even when preprocessing. fpermissive -C++ ObjC++ Var(flag_permissive) +C ObjC C++ ObjC++ Var(flag_permissive) Downgrade conformance errors to warnings. fplan9-extensions diff --git a/gcc/doc/invoke.texi b/gcc/doc/invoke.texi index 6e776a0faa1..dfa01220b93 100644 --- a/gcc/doc/invoke.texi +++ b/gcc/doc/invoke.texi @@ -6170,13 +6170,17 @@ errors by @option{-pedantic-errors}. For instance: Downgrade some required diagnostics about nonconformant code from errors to warnings. Thus, using @option{-fpermissive} allows some nonconforming code to compile. Some C++ diagnostics are controlled -only by this flag, but it also downgrades some diagnostics that have -their own flag: +only by this flag, but it also downgrades some C and C++ diagnostics +that have their own flag: @gccoptlist{ -Wnarrowing @r{(C++)} } +The @option{-fpermissive} option is the default for historic C language +modes (@option{-std=c89}, @option{-std=gnu89}, @option{-std=c90}, +@option{-std=gnu90}). + @opindex Wall @opindex Wno-all @item -Wall base-commit: 3cc9ad41db87fb85b13a56bff1f930c258542a70