[PATCH] D40604: [GlobalISel][IRTranslator] Fix crash during translation of zero sized loads and stores

[Amara Emerson via llvm-commits]

SDAGBuilder doesn’t create anything for loads and stores if the operands are zero size.

Amara

> On Nov 29, 2017, at 5:40 PM, Quentin Colombet <qcolombet at apple.com> wrote:
> 
> What does SDISel do in those situations?
> 
>> On Nov 29, 2017, at 9:27 AM, Amara Emerson via Phabricator via llvm-commits <llvm-commits at lists.llvm.org> wrote:
>> 
>> aemerson added inline comments.
>> 
>> 
>> ================
>> Comment at: lib/CodeGen/GlobalISel/IRTranslator.cpp:340-341
>> 
>> +  if (DL->getTypeStoreSize(LI.getType()) == 0)
>> +    return true;
>> +
>> ----------------
>> dsanders wrote:
>>> I'm not sure this is correct for the load. If the load result has a use then I'd expect -verify-machineinstrs to complain about a missing def. I think we need to emit an IMPLICIT_DEF.
>> That would require getting an LLT for a zero size type to create a vreg and running into the initial cause of the crash.
>> 
>> Also, is there anything meaningful you can do with the load result? You can't bitcast it to anything (I think?) and storing it won't result in a store being generated, so no instructions are emitted for the verifier.
>> 
>> 
>> Repository:
>> rL LLVM
>> 
>> https://reviews.llvm.org/D40604
>> 
>> 
>> 
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