[llvm-dev] uninitialized values in Attributes.cpp

[Hal Finkel via llvm-dev]

----- Original Message -----
> From: "regehr via llvm-dev" <llvm-dev at lists.llvm.org>
> To: "Mehdi Amini" <mehdi.amini at apple.com>
> Cc: "llvm-dev" <llvm-dev at lists.llvm.org>
> Sent: Sunday, November 20, 2016 5:50:35 PM
> Subject: Re: [llvm-dev] uninitialized values in Attributes.cpp
> 
> > If 3.9 shipped with these issues (assuming these are not false
> > positive), it would be interesting to 1) know why the sanitizers
> > didn’t catch it, and 2) add valgrind to the release qualification
> > process (CC Hans).
> 
> Yes, I'd be interested to see some corroboration.

We should first confirm that there is actually a problem. At least on some platforms (e.g. PowerPC), valgrind's ability to accurately track uses of undefined data is limited.

 -Hal

>  Note that the
> issue
> here is pretty specific: it only happens during optimized compile
> using
> Clang-3.9.
> 
> This is all I did:
> 
> 1. checkout LLVM/clang trunk
> 
> 2. make sure clang in path is clang-3.9
> 
> 3.
> 
> cmake .. -GNinja -DCMAKE_BUILD_TYPE=RelWithDebInfo
> -DLLVM_ENABLE_ASSERTIONS=On -DCMAKE_CXX_COMPILER=clang++
> -DCMAKE_C_COMPILER=clang -DLLVM_LIT_ARGS="-v --vg"
> 
> 4.
> 
> ninja check
> 
> John
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-- 
Hal Finkel
Lead, Compiler Technology and Programming Languages
Leadership Computing Facility
Argonne National Laboratory