[llvm] [ExtendLifetimes] Implement llvm.fake.use to extend variable lifetimes (PR #86149)

[Matt Arsenault via llvm-commits]

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@@ -0,0 +1,17 @@
+; assert in DAGlegalizer with fake use of half precision float.
+; Changes to half float promotion.
+; RUN: llc -O2 -stop-after=finalize-isel -filetype=asm -o - %s | FileCheck %s
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arsenm wrote:

-O2 and -filetype=asm are the defaults 

https://github.com/llvm/llvm-project/pull/86149