[PATCH] D17983: Eliminate many benign instances of "potentially uninitialized local variable" warnings

Teresa Johnson via cfe-commits cfe-commits at lists.llvm.org
Wed Mar 9 08:18:32 PST 2016


On Wed, Mar 9, 2016 at 8:13 AM, David Blaikie <dblaikie at gmail.com> wrote:

>
> On Mar 9, 2016 8:11 AM, "Teresa Johnson via llvm-commits" <
> llvm-commits at lists.llvm.org> wrote:
> >
> > tejohnson added a subscriber: tejohnson.
> > tejohnson added a comment.
> >
> > Thanks for doing this!
> >
> > I will fix these 3, which one of my changes would have provoked. It is a
> benign case since we do have an assert at the use site checking the same
> condition that the inits are guarded with, but there is no reason not to 0
> init these to avoid the bogus warning.
>
> The reason not to is that it would silence msan catching the unintentional
> codepath (eg: if you didn't have the assert there, and they init and use
> conditions didn't match, msan would tell us - if we add what we believe to
> be a dead init, then msan no longer helps us here)
>

Hmm, ok. It's unfortunate that the warning and msan are at odds, although I
don't know how to reconcile them. Will leave as is then. Is it worth a
comment indicating why we are leaving them uninitialized?

> >
> > Warning C4701   potentially uninitialized local variable
> 'FnEntry8BitAbbrev' used       LLVMBitWriter
>  c:\llvm\llvm\lib\bitcode\writer\bitcodewriter.cpp       2353
> > Warning C4701   potentially uninitialized local variable
> 'FnEntry7BitAbbrev' used       LLVMBitWriter
>  c:\llvm\llvm\lib\bitcode\writer\bitcodewriter.cpp       2357
> > Warning C4701   potentially uninitialized local variable
> 'FnEntry6BitAbbrev' used       LLVMBitWriter
>  c:\llvm\llvm\lib\bitcode\writer\bitcodewriter.cpp       2355
> >
> >
> > http://reviews.llvm.org/D17983
> >
> >
> >
> > _______________________________________________
> > llvm-commits mailing list
> > llvm-commits at lists.llvm.org
> > http://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-commits
>



-- 
Teresa Johnson |  Software Engineer |  tejohnson at google.com |  408-460-2413
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