[PATCH] D134641: [AMDGPU][Backend] Fix user-after-free in AMDGPUReleaseVGPRs::isLastVGPRUseVMEMStore

[Juan Manuel Martinez Caamaño via Phabricator via llvm-commits]

jmmartinez added inline comments.


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Comment at: llvm/lib/Target/AMDGPU/AMDGPUReleaseVGPRs.cpp:43
   // Used to cache the result of isLastInstructionVMEMStore for each block
   using BlockVMEMStoreType = DenseMap<MachineBasicBlock *, bool>;
   BlockVMEMStoreType BlockVMEMStore;
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arsenm wrote:
> If you're going to resize to the number of blocks, do you really need to use a DenseMap at all? You could use a bit vector indexed by the block number 
It doesn't map direclty into a bit-vector since there are 3 states considered (has-a-vmem-store, does-not-have-vmem-store and not-yet-computed).

What do you think about a `SmallVector<VMEMStore>` with an `enum class UsesVMEMStoreTy { UsesVMEMStore, DoesNotUseVMEMStore, NotYetComputed }` ?


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  https://reviews.llvm.org/D134641/new/

https://reviews.llvm.org/D134641