[llvm] [LegalizeDAG] PromoteNode FABS: Override promotion with clear sign bit (PR #106076)

[Matt Arsenault via llvm-commits]

arsenm wrote:

This should be resurrected. The promotion to float through fpext is simply wrong. There should be no fall through for it, it should fail 

https://github.com/llvm/llvm-project/pull/106076