[clang] [HLSL][Matrix] Load and store ConstantMatrixBoolTypes as i32 FixedVectorTypes (PR #175245)

[Farzon Lotfi via cfe-commits]

https://github.com/farzonl approved this pull request.

LGTM. One nit to use `getNumElementsFlattened` and one clarification needed on why we don't need to check language mode for the zext case?

https://github.com/llvm/llvm-project/pull/175245