[llvm] [SandboxIR][SandboxVectorizer][NFC] Move Region to SandboxVectorizer. (PR #117237)

[Jorge Gorbe Moya via llvm-commits]

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@@ -107,6 +109,25 @@ class Region {
 #endif
 };
 
+/// A pass that runs on a Region.
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slackito wrote:

All the Region-related stuff is currently already in SandboxIR, so "move it into SandboxIR" is just dropping this PR (which is, of course, an option). Or were you talking about something different?

https://github.com/llvm/llvm-project/pull/117237