[llvm] [RegAlloc] Scale the spill weight by the weight of register class (PR #113675)

[Ulrich Weigand via llvm-commits]

uweigand wrote:

> I have some impressions about this test `cond-move-regalloc-hints.mir` when fixing these tests that are not using `utils/update_llc_test_checks.py`. :-)

Ah, you're right, that is an improvement.  The test probably should switch to auto-generated, so that it's clearer what it tests ...

https://github.com/llvm/llvm-project/pull/113675