Re: [PATCH 1/2] fast-import: Fix an gcc -Wuninitialized warning

[Ramsay Jones <ramsay@ramsay1.demon.co.uk>]

Jeff King wrote:
> On Tue, Mar 26, 2013 at 07:09:44PM +0000, Ramsay Jones wrote:
> 
>> Commit cbfd5e1c ("drop some obsolete "x = x" compiler warning hacks",
>> 21-03-2013) removed a gcc hack that suppressed an "might be used
>> uninitialized" warning issued by older versions of gcc.
>>
>> However, commit 3aa99df8 ('fast-import: clarify "inline" logic in
>> file_change_m', 21-03-2013) addresses an (almost) identical issue
>> (with very similar code), but includes additional code in it's
>> resolution. The solution used by this commit, unlike that used by
>> commit cbfd5e1c, also suppresses the -Wuninitialized warning on
>> older versions of gcc.
>>
>> In order to suppress the warning (against the 'oe' symbol) in the
>> note_change_n() function, we adopt the same solution used by commit
>> 3aa99df8.
> 
> Yeah, they are essentially the same piece of code, so I don't mind this
> change.  It is odd to me that gcc gets it right in one case but not the
> other, but I think we are deep into the vagaries of the compiler's code
> flow analysis here, and we cannot make too many assumptions.
> 
> Were you actually triggering this warning, and if so, on what version of
> gcc? 

yes, with:
    gcc v3.4.4 (cygwin)
    gcc v4.1.2 (Linux)
    msvc v15.00.30729.01 (VC/C++ 2008 express edition)
no, with:
    gcc v4.4.0 (msysgit)
    clang 3.2 (Linux)
    tcc v0.9.26 (Linux)
[lcc can't compile git; I forget why exactly.]

>       Or did the asymmetry just offend your sensibilities?

My sensibilities were, indeed, very offended! ;-)

ATB,
Ramsay Jones