[Bug other/53313] Add warning levels

["manu at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=53313

Manuel López-Ibáñez <manu at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Keywords|                            |easyhack

--- Comment #7 from Manuel López-Ibáñez <manu at gcc dot gnu.org> ---
It doesn't make sense to really enable every -Wx option, some of them are too
specialized (-Wdouble-promotion, -Wtraditional, -Wlarger-than=, -Wc++-compat,
etc.)

However, if someone goes through the trouble of compiling a list of potential
candidates, it should be trivial to implement using EnabledBy() in common.opt,
c.opt, etc.

Now I think the original proposal of having warnings levels is not what GCC
wants. In fact, we now have -Ofast, -Os, and -Og and the consensus seems to be
that we do not want to have -O4. According to
https://gcc.gnu.org/wiki/DiagnosticsGuidelines

<quote>
* enabled by default if it has (almost) no false positives (e.g., -Woverflow);

* added to -Wall if it is generally useful with low number of false positives
that are easy to work-around;

* added to -Wextra if it has quite a lot of false positives but they are still
easy to work-around; 

Warning options should move up in this list when bugfixes reduce the number of
false positives. These cases are not meant to be exhaustive: some options
should never be enabled by other option if the warning is too specific
(-Wdouble-promotion); other options are already controlled by options such as
-Wpedantic and -Wformat and do not need to move up in this list (but they might
if deemed useful).
</quote>

We could add:

* always added to -Weverything unless the warning was never meant to be
generally useful even if it were perfect (-Wdouble-promotion, -Wtraditional,
-Wlarger-than=, -Wc++-compat, etc.).
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From: "gjl at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug target/65296] [avr] fix various issues with specs file generation
Date: Wed, 22 Apr 2015 16:15:00 -0000
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https://gcc.gnu.org/bugzilla/show_bug.cgi?ide296

--- Comment #10 from Georg-Johann Lay <gjl at gcc dot gnu.org> ---
Author: gjl
Date: Wed Apr 22 16:14:50 2015
New Revision: 222333

URL: https://gcc.gnu.org/viewcvs?rev"2333&root=gcc&view=rev
Log:
    Backport from trunk r222179.
    2015-04-17  Sivanupandi Pitchumani <Pitchumani.Sivanupandi@atmel.com>
    PR target/65296
    * config/avr/gen-avr-mmcu-specs.c (*avrlibc_startfile): Adjust
    to new AVR-LibC file layout (bug #44574).
    (*avrlibc_devicelib): Same.
    * config/avr/avr-mcus.def: Adjust comments.
    * config/avr/avr.opt (nodevicelib): Adjust help.


Modified:
    branches/gcc-5-branch/gcc/ChangeLog
    branches/gcc-5-branch/gcc/config/avr/avr-mcus.def
    branches/gcc-5-branch/gcc/config/avr/avr.opt
    branches/gcc-5-branch/gcc/config/avr/gen-avr-mmcu-specs.c