[Bug c/58236] -Wuninitialized doesn't report uninitialised variable as expected

[glisse at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=58236

--- Comment #1 from Marc Glisse <glisse at gcc dot gnu.org> ---
Note, from the documentation of -Wuninitialized:

"Because these warnings depend on optimization, the exact variables or elements
for which there are warnings depends on the precise optimization options and
version of GCC used."

You need to pass -O2 on the command line, and then you'll get warnings.