[llvm] [IR][ASMParser] Use default AS for alloca without explicit AS (PR #135786)

[Fabian Ritter via llvm-commits]

ritter-x2a wrote:

Then we should probably change the langref instead. There is also the point that the bitcode reader/writer represents an alloca with the default address space by omitting the address space record; I guess it might be sufficiently unlikely to see inconsistencies because of that.

https://github.com/llvm/llvm-project/pull/135786