[llvm-dev] funnel shift, select, and poison

[John Regehr via llvm-dev]

Poison has to propagate through calls and loads/stores, or else 
basically nothing works.

John



On 2/25/19 10:29 AM, Krzysztof Parzyszek via llvm-dev wrote:
> On 2/25/2019 11:15 AM, John Regehr via llvm-dev wrote:
>> I'd just like to add that the general question here is "where does 
>> poison stop propagating" and this question needs to be definitively 
>> answered by this community.
> 
> Does a call stop poison?
> 
> Whatever the decision is may be contradicted after inlining, so what 
> should such a call return?  A superposition of poison and non-poison, 
> until the function is inlined? It's a serious question.
> 
> -Krzysztof
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