[llvm] [AArch64] Return early rather than asserting when Size of value passed to targetShrinkDemandedConstant is not 32 or 64 (PR #123084)

[Will Froom via llvm-commits]

WillFroom wrote:

@davemgreen thanks for the review, I am waiting on commit access (https://github.com/llvm/llvm-project/issues/122733) so if you are happy could you press merge, cheers.

https://github.com/llvm/llvm-project/pull/123084