Binutils 2.47 fails to build with warning 'exp.X_op' may be used uninitialized

[Alan Modra]

On Sat, Aug 08, 2026 at 07:47:12PM +0200, R. Diez via Binutils wrote:
> Hi all:
> 
> Binutils 2.47 fails to build with this error message:
> 
> -------8<-------8<-------
> 
>   CCLD     as-new
> /home/rdiez/blah.../binutils-2.47/gas/config/tc-arm.c: In function 'parse_immediate.constprop':
> /home/rdiez/blah.../binutils-2.47/gas/config/tc-arm.c:5198:10: error: 'exp.X_op' may be used uninitialized [-Werror=maybe-uninitialized]
>  5198 |   if (exp.X_op != O_constant)
>       |          ^
> /home/rdiez/blah.../binutils-2.47/gas/config/tc-arm.c:5195:15: note: 'exp' declared here
>  5195 |   expressionS exp;
>       |               ^
> lto1: all warnings being treated as errors
> 
> -------8<-------8<-------
> 
> Is this a known issue? The older Binutils 2.46.1 builds fine in the same setup.

exp.X_op can indeed be used uninitialised.  You found a real error,
one that has been there for quite a while.   2.46 built OK because
usually we turn off -Werror on releases, but somehow that was
forgotten for 2.47.

-- 
Alan Modra