[llvm] [LoopPeel] Peel last iteration to enable load widening (PR #173420)

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``````````bash
git-clang-format --diff origin/main HEAD --extensions h,cpp -- llvm/include/llvm/IR/DataLayout.h llvm/include/llvm/Transforms/Utils/LoopPeel.h llvm/include/llvm/Transforms/Utils/UnrollLoop.h llvm/lib/Transforms/Scalar/LoopUnrollPass.cpp llvm/lib/Transforms/Utils/LoopPeel.cpp llvm/lib/Transforms/Vectorize/VectorCombine.cpp --diff_from_common_commit
``````````

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``````````diff
diff --git a/llvm/lib/Transforms/Scalar/LoopUnrollPass.cpp b/llvm/lib/Transforms/Scalar/LoopUnrollPass.cpp
index 585d6799d..184282247 100644
--- a/llvm/lib/Transforms/Scalar/LoopUnrollPass.cpp
+++ b/llvm/lib/Transforms/Scalar/LoopUnrollPass.cpp
@@ -1033,18 +1033,15 @@ shouldPartialUnroll(const unsigned LoopSize, const unsigned TripCount,
 // FIXME: This function is used by LoopUnroll and LoopUnrollAndJam, but consumes
 // many LoopUnroll-specific options. The shared functionality should be
 // refactored into it own function.
-void llvm::computeUnrollCount(Loop *L, const TargetTransformInfo &TTI,
-                              DominatorTree &DT, LoopInfo *LI,
-                              AssumptionCache *AC, ScalarEvolution &SE,
-                              const SmallPtrSetImpl<const Value *> &EphValues,
-                              OptimizationRemarkEmitter *ORE,
-                              const unsigned TripCount,
-                              const unsigned MaxTripCount, const bool MaxOrZero,
-                              const unsigned TripMultiple,
-                              const UnrollCostEstimator &UCE,
-                              TargetTransformInfo::UnrollingPreferences &UP,
-                              TargetTransformInfo::PeelingPreferences &PP,
-                              bool AllowLoadWideningPeel) {
+void llvm::computeUnrollCount(
+    Loop *L, const TargetTransformInfo &TTI, DominatorTree &DT, LoopInfo *LI,
+    AssumptionCache *AC, ScalarEvolution &SE,
+    const SmallPtrSetImpl<const Value *> &EphValues,
+    OptimizationRemarkEmitter *ORE, const unsigned TripCount,
+    const unsigned MaxTripCount, const bool MaxOrZero,
+    const unsigned TripMultiple, const UnrollCostEstimator &UCE,
+    TargetTransformInfo::UnrollingPreferences &UP,
+    TargetTransformInfo::PeelingPreferences &PP, bool AllowLoadWideningPeel) {
 
   unsigned LoopSize = UCE.getRolledLoopSize();
 
@@ -1150,7 +1147,8 @@ void llvm::computeUnrollCount(Loop *L, const TargetTransformInfo &TTI,
 
   // 5th priority is loop peeling.
   LLVM_DEBUG(dbgs().indent(1) << "Trying loop peeling...\n");
-  computePeelCount(L, LoopSize, PP, TripCount, DT, SE, TTI, AC, UP.Threshold, AllowLoadWideningPeel);
+  computePeelCount(L, LoopSize, PP, TripCount, DT, SE, TTI, AC, UP.Threshold,
+                   AllowLoadWideningPeel);
   if (PP.PeelCount) {
     LLVM_DEBUG(dbgs().indent(2)
                << "Peeling with count: " << PP.PeelCount << ".\n");
@@ -1420,7 +1418,8 @@ tryToUnrollLoop(Loop *L, DominatorTree &DT, LoopInfo *LI, ScalarEvolution &SE,
   // fully unroll the loop.
   bool AllowLoadWideningPeel = !OnlyFullUnroll;
   computeUnrollCount(L, TTI, DT, LI, &AC, SE, EphValues, &ORE, TripCount,
-                     MaxTripCount, MaxOrZero, TripMultiple, UCE, UP, PP, AllowLoadWideningPeel);
+                     MaxTripCount, MaxOrZero, TripMultiple, UCE, UP, PP,
+                     AllowLoadWideningPeel);
   if (!UP.Count) {
     LLVM_DEBUG(dbgs().indent(1)
                << "Not unrolling: no viable strategy found.\n");

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https://github.com/llvm/llvm-project/pull/173420