[llvm] [VPlan] Support early-exit loops in optimizeForVFAndUF. (PR #131539)

[David Sherwood via llvm-commits]

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@@ -1005,6 +1005,33 @@ void VPlanTransforms::simplifyRecipes(VPlan &Plan, Type &CanonicalIVTy) {
   }
 }
 
+/// Return true if \p Cond is known to be true for given \p BestVF and \p
+/// BestUF.
+static bool isConditionKnown(VPValue *Cond, VPlan &Plan, ElementCount BestVF,
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david-arm wrote:

The condition could be known to be either false or true, so to avoid ambiguity perhaps this should be renamed to `isBranchConditionKnownTrue`? I also think adding the word `Branch` indicates the condition relates to the terminator branch condition, as opposed to the condition for a select, etc.

https://github.com/llvm/llvm-project/pull/131539