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[Bug tree-optimization/66946] Spurious uninitialized warning
- From: "wdijkstr at arm dot com" <gcc-bugzilla at gcc dot gnu dot org>
- To: gcc-bugs at gcc dot gnu dot org
- Date: Tue, 21 Jul 2015 13:42:26 +0000
- Subject: [Bug tree-optimization/66946] Spurious uninitialized warning
- Auto-submitted: auto-generated
- References: <bug-66946-4 at http dot gcc dot gnu dot org/bugzilla/>
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=66946
--- Comment #4 from Wilco <wdijkstr at arm dot com> ---
(In reply to Andrew Pinski from comment #2)
> Comment on attachment 36021 [details]
> minimal example
>
> written == ((wchar_t) 0xfffd)
>
> Will ever be true or is there some sign extending going on which causes this
> to be false for the default case?
The issue seems related to signextension indeed. My GCC builds include this
patch: https://gcc.gnu.org/ml/gcc-patches/2015-05/msg00005.html
When I disable this new phase the warning disappears, so it might be due to a
transformation it makes. The generated code is virtually identical, just
different register allocation.