[llvm] r372743 - ConstantFold - silence static analyzer dyn_cast<> null dereference warning. NFCI.

[David Blaikie via llvm-commits]

Because the condition comes from a Constant it must itself be a Constant?
Could you change it to a cast<> then?

On Tue, Oct 1, 2019 at 1:31 AM Simon Pilgrim <llvm-dev at redking.me.uk> wrote:

> TBH I think was being over cautious - we should be able to just use
> cast<Constant> as we've already confirmed that CondV is a ConstantVector
> On 30/09/2019 21:35, David Blaikie wrote:
>
> Any test coverage for this codepath?
>
> On Tue, Sep 24, 2019 at 5:28 AM Simon Pilgrim via llvm-commits <
> llvm-commits at lists.llvm.org> wrote:
>
>> Author: rksimon
>> Date: Tue Sep 24 05:30:13 2019
>> New Revision: 372743
>>
>> URL: http://llvm.org/viewvc/llvm-project?rev=372743&view=rev
>> Log:
>> ConstantFold - silence static analyzer dyn_cast<> null dereference
>> warning. NFCI.
>>
>> Early out if the vector element is not Constant.
>>
>> Modified:
>>     llvm/trunk/lib/IR/ConstantFold.cpp
>>
>> Modified: llvm/trunk/lib/IR/ConstantFold.cpp
>> URL:
>> http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/IR/ConstantFold.cpp?rev=372743&r1=372742&r2=372743&view=diff
>>
>> ==============================================================================
>> --- llvm/trunk/lib/IR/ConstantFold.cpp (original)
>> +++ llvm/trunk/lib/IR/ConstantFold.cpp Tue Sep 24 05:30:13 2019
>> @@ -747,6 +747,7 @@ Constant *llvm::ConstantFoldSelectInstru
>>        Constant *V2Element = ConstantExpr::getExtractElement(V2,
>>                                                      ConstantInt::get(Ty,
>> i));
>>        Constant *Cond = dyn_cast<Constant>(CondV->getOperand(i));
>> +      if (!Cond) break;
>>        if (V1Element == V2Element) {
>>          V = V1Element;
>>        } else if (isa<UndefValue>(Cond)) {
>>
>>
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>
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