[clang] [llvm] [SPIRV] add pre legalization instruction combine (PR #122839)

[Farzon Lotfi via llvm-commits]

farzonl wrote:

> @farzonl Was enabled GISelCSEAnalysisWrapperPass a reason of problems with inline_asm?

It was CSE and The combiner pass does dead code elimination. I removed one and turned the other off. Their is a bug in the SPIRVPreLegalizer where its expecting a matching number of inline asm and the spv inline asm intrinsics. Im not sure what the fix for the bug should be so it was simpler to just turn off cse and dce.

https://github.com/llvm/llvm-project/pull/122839