[llvm] r297971 - Salvage debug info from instructions about to be deleted

[Evgenii Stepanov via llvm-commits]

I can confirm the reverting this change helps. Would you mind doing
that? It's pretty bad, check-msan just nearly killed my machine.

I'm working on a test case.

On Thu, Mar 16, 2017 at 1:15 PM, Adrian Prantl <aprantl at apple.com> wrote:
> Is there a bot that catches this or otherwise any instructions to reproduce this?
>
> thanks,
> adrian
>
>> On Mar 16, 2017, at 1:13 PM, Evgenii Stepanov <eugeni.stepanov at gmail.com> wrote:
>>
>> Hi,
>>
>> ninja check-msan on linux/x86_64 has started using unlimited memory
>> and I suspect this change.
>> One common allocation is
>>
>> #9 0x00007f40f6cfae0d operator new(unsigned long)
>> /build/gcc-4.8-mW1ufQ/gcc-4.8-4.8.4/build/x86_64-linux-gnu/libstdc++-v3/libsupc++/../../../../src/libstdc++-v3/libsupc++/new_op.cc:56:0
>> #10 0x00000000017e3a8d llvm::DIExpression::getImpl(llvm::LLVMContext&,
>> llvm::ArrayRef<unsigned long>, llvm::Metadata::StorageType, bool)
>> (/code/build-llvm/bin/clang-5.0+0x17e3a8d)
>> #11 0x0000000001dae195 prependDIExpr(llvm::DIBuilder&,
>> llvm::DIExpression*, bool, long)
>> (/code/build-llvm/bin/clang-5.0+0x1dae195)
>> #12 0x0000000001db539b std::_Function_handler<void
>> (llvm::DbgValueInst&),
>> llvm::salvageDebugInfo(llvm::Instruction&)::$_2>::_M_invoke(std::_Any_data
>> const&, llvm::DbgValueInst&)
>> (/code/build-llvm/bin/clang-5.0+0x1db539b)
>> #13 0x0000000001dade35 llvm::findDbgValues(llvm::Value*,
>> std::function<void (llvm::DbgValueInst&)>)
>> (/code/build-llvm/bin/clang-5.0+0x1dade35)
>> #14 0x0000000001dae7f6 llvm::salvageDebugInfo(llvm::Instruction&)
>> (/code/build-llvm/bin/clang-5.0+0x1dae7f6)
>> #15 0x0000000001961964
>> llvm::InstCombiner::eraseInstFromFunction(llvm::Instruction&)
>> (/code/build-llvm/bin/clang-5.0+0x1961964)
>> #16 0x000000000196deb5 llvm::InstCombiner::run()
>> (/code/build-llvm/bin/clang-5.0+0x196deb5)
>>
>>
>