[llvm] [RISCV] Pass sign-extended value to isInt check in expandMul (PR #150211)

[Sudharsan Veeravalli via llvm-commits]

svs-quic wrote:

> Is it possible to test?

I am not sure how to test this. I noticed that with the current logic negative numbers in the isInt<12> range would fail the check since they would show up as large unsigned values. I am able to verify the fix locally by adding some debug logs but not sure how to translate this into a test case. I'll think about this and probably add a test case as a follow-up.

https://github.com/llvm/llvm-project/pull/150211