[llvm] [PGO] Add `llvm.loop.estimated_trip_count` metadata (PR #148758)

[Mircea Trofin via llvm-commits]

================
@@ -869,9 +951,9 @@ bool llvm::setLoopEstimatedTripCount(Loop *L, unsigned EstimatedTripCount,
   unsigned LatchExitWeight = 0;
   unsigned BackedgeTakenWeight = 0;
 
-  if (EstimatedTripCount > 0) {
-    LatchExitWeight = EstimatedloopInvocationWeight;
-    BackedgeTakenWeight = (EstimatedTripCount - 1) * LatchExitWeight;
+  if (*EstimatedTripCount > 0) {
----------------
mtrofin wrote:

Nit: since it's an unsigned, `*EstimatedTripCount != 0`?

https://github.com/llvm/llvm-project/pull/148758