[cfe-commits] [PATCH] Fix uninitialized variable tracking for compound assignments

[Ted Kremenek]

On Jul 15, 2012, at 10:14 PM, Richard Smith <richard at metafoo.co.uk> wrote:

> The patch replaces the 'track the last DeclRefExpr we saw' technique with a separate pass to classify the DeclRefExprs as use or initialization. Fixing this exposed some "false" positives on some benchmarking code which looks like:
> 
> void f() {
>   volatile int n;
>   for (int i = 0; i < N; ++i)
>     n += f();
> }
> 
> ... so the patch classifies compound-assignments as neither initialization nor use (it leaves the variable uninitialized if it was before, and leaves it initialized if it was before).
> 

Hi Richard,

One comment on this last point.  We tend to like avoiding the uninitialized value taint propagating after the first use to avoid a cascade of warnings.  Your last comment here implies that were we to flag a warning at "n += f()" we might also flag another warning later if 'n' is used again.  Is that true?

Ted
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