[llvm] [VectorCombine][TTI] Disable Load Widening for SPIR-V (PR #227623)

[Gregory Roth via llvm-commits]

pow2clk wrote:

> Can't you just adjust the costs with SPIRVTTIImpl::getMemoryOpCost?

Thanks for the prompt response! 

I explored that possibility, but ultimately modeled this after #150216. Are you suggesting inserting an arbitrarily large cost for SPIR-V or something more detailed? 

https://github.com/llvm/llvm-project/pull/227623