[llvm] Refine the examples in the debug info document (PR #86272)

[Jeremy Morse via llvm-commits]

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@@ -91,8 +91,12 @@ misattributed to a block containing one of the instructions-to-be-merged.
 
 Examples of transformations that should follow this rule include:
 
-* Merging identical loads/stores which occur on both sides of a CFG diamond
-  (see the ``MergedLoadStoreMotion`` pass).
+* Hoisting identical instructions from all successors of a conditional branch
+  or sinking those from all different predecessors. For example, merging
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jmorse wrote:

I feel "from all different predecessors" would be better written "from all paths to a postdominating block". The term postdominating should put the reader in mind of the sort of CFG you're describing.

https://github.com/llvm/llvm-project/pull/86272