[llvm] [NFC][AMDGPU][SIMemoryLegalizer] remove effectively empty function (PR #156806)

[Sameer Sahasrabuddhe via llvm-commits]

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@@ -443,10 +443,6 @@ class SIGfx90ACacheControl : public SIGfx7CacheControl {
                              SIAtomicScope Scope,
                              SIAtomicAddrSpace AddrSpace) const override;
 
-  bool enableStoreCacheBypass(const MachineBasicBlock::iterator &MI,
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ssahasra wrote:

I don't think that's necessary. There are other CacheControl classes in the same file that skip this function without a comment. And in general, that's the expected usage of a virtual function, right? If the derived class does not override the base class, then the base class applies by default.

https://github.com/llvm/llvm-project/pull/156806