[llvm] [ARM] Reduce loop unroll when low overhead branching is available (PR #120065)

[David Green via llvm-commits]

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@@ -2592,11 +2592,23 @@ void ARMTTIImpl::getUnrollingPreferences(Loop *L, ScalarEvolution &SE,
       return;
   }
 
+  bool Runtime = true;
+  if (ST->hasLOB()) {
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davemgreen wrote:

Can you add a comment explaining the reason?

https://github.com/llvm/llvm-project/pull/120065