On 11/10/2007, Roberto Bagnara <[EMAIL PROTECTED]> wrote: > > Just to make sure before I submit a bug report: when GCC says that > a certain variable _is_ (as opposed to _may be_) used uninitialized > in this function, it means that it has proved that the variable > is indeed used uninitialized, right?
When GCC says that a certain variable "is used" uninitialized, it just means that it has found a SSA name with an empty definition in a particular BB. That proves nothing about a variable being used uninitialized, since, that BB may be conditional or it may not even be executed at all. Nonetheless, this is not the desirable behaviour so, please submit a bug report and if possible, attach the smallest self-contained testcase and the *.ssa file obtained by adding the option -fdump-tree-all-all. Please add manu at gcc dot gnu dot org to the CC list. > I am asking because I have a testcase where g++ gives this warning for > `z' in the statement marked with (***) below. However, `z' is indeed > initialized by the mul() function template, which takes the first > argument by (non-const) reference: The current Wuninitialized mechanism does not handle memory references well (it does not handle virtual operands at all), so it gets easily confused by pointers, references, arrays, etc. I am almost sure that the wrong warning is a consequence of the combination of this and the previously mentioned issues. Thanks, Manuel.
