[llvm] d77f944 - [LoopInfo] Add getOutermostLoop() (NFC)

[Nikita Popov via llvm-commits]

Author: Nikita Popov
Date: 2022-06-10T11:48:21+02:00
New Revision: d77f944832ae6fcb33397072c717c7971df6d3ee

URL: https://github.com/llvm/llvm-project/commit/d77f944832ae6fcb33397072c717c7971df6d3ee
DIFF: https://github.com/llvm/llvm-project/commit/d77f944832ae6fcb33397072c717c7971df6d3ee.diff

LOG: [LoopInfo] Add getOutermostLoop() (NFC)

This is a recurring pattern, add an API function for it.

Added: 
    

Modified: 
    llvm/include/llvm/Analysis/LoopInfo.h
    llvm/include/llvm/Analysis/LoopInfoImpl.h
    llvm/lib/Analysis/CFG.cpp
    llvm/lib/Analysis/DependenceAnalysis.cpp
    llvm/lib/Analysis/ScalarEvolution.cpp
    llvm/lib/Transforms/Utils/LoopUtils.cpp

Removed: 
    


################################################################################
diff  --git a/llvm/include/llvm/Analysis/LoopInfo.h b/llvm/include/llvm/Analysis/LoopInfo.h
index 8bef178dda18b..9351b83ad7479 100644
--- a/llvm/include/llvm/Analysis/LoopInfo.h
+++ b/llvm/include/llvm/Analysis/LoopInfo.h
@@ -112,6 +112,22 @@ template <class BlockT, class LoopT> class LoopBase {
   /// parent is the innermost loop in which it is enclosed.
   LoopT *getParentLoop() const { return ParentLoop; }
 
+  /// Get the outermost loop in which this loop is contained.
+  /// This may be the loop itself, if it already is the outermost loop.
+  const LoopT *getOutermostLoop() const {
+    const LoopT *L = static_cast<const LoopT *>(this);
+    while (L->ParentLoop)
+      L = L->ParentLoop;
+    return L;
+  }
+
+  LoopT *getOutermostLoop() {
+    LoopT *L = static_cast<LoopT *>(this);
+    while (L->ParentLoop)
+      L = L->ParentLoop;
+    return L;
+  }
+
   /// This is a raw interface for bypassing addChildLoop.
   void setParentLoop(LoopT *L) {
     assert(!isInvalid() && "Loop not in a valid state!");

diff  --git a/llvm/include/llvm/Analysis/LoopInfoImpl.h b/llvm/include/llvm/Analysis/LoopInfoImpl.h
index fdaa6df8832fe..a96a698f3afbc 100644
--- a/llvm/include/llvm/Analysis/LoopInfoImpl.h
+++ b/llvm/include/llvm/Analysis/LoopInfoImpl.h
@@ -453,8 +453,7 @@ static void discoverAndMapSubloop(LoopT *L, ArrayRef<BlockT *> Backedges,
                                 InvBlockTraits::child_end(PredBB));
     } else {
       // This is a discovered block. Find its outermost discovered loop.
-      while (LoopT *Parent = Subloop->getParentLoop())
-        Subloop = Parent;
+      Subloop = Subloop->getOutermostLoop();
 
       // If it is already discovered to be a subloop of this loop, continue.
       if (Subloop == L)

diff  --git a/llvm/lib/Analysis/CFG.cpp b/llvm/lib/Analysis/CFG.cpp
index ec25ee161e2cf..1902d72f2f89b 100644
--- a/llvm/lib/Analysis/CFG.cpp
+++ b/llvm/lib/Analysis/CFG.cpp
@@ -127,11 +127,7 @@ bool llvm::isCriticalEdge(const Instruction *TI, const BasicBlock *Dest,
 // the outermost loop in the loop nest that contains BB.
 static const Loop *getOutermostLoop(const LoopInfo *LI, const BasicBlock *BB) {
   const Loop *L = LI->getLoopFor(BB);
-  if (L) {
-    while (const Loop *Parent = L->getParentLoop())
-      L = Parent;
-  }
-  return L;
+  return L ? L->getOutermostLoop() : nullptr;
 }
 
 bool llvm::isPotentiallyReachableFromMany(

diff  --git a/llvm/lib/Analysis/DependenceAnalysis.cpp b/llvm/lib/Analysis/DependenceAnalysis.cpp
index 1c6a99ea788f1..1778b4617ec2d 100644
--- a/llvm/lib/Analysis/DependenceAnalysis.cpp
+++ b/llvm/lib/Analysis/DependenceAnalysis.cpp
@@ -803,10 +803,7 @@ bool DependenceInfo::isLoopInvariant(const SCEV *Expression,
 
   // If the expression is invariant in the outermost loop of the loop nest, it
   // is invariant anywhere in the loop nest.
-  const Loop *OutermostLoop = LoopNest;
-  while (OutermostLoop->getParentLoop())
-    OutermostLoop = OutermostLoop->getParentLoop();
-  return SE->isLoopInvariant(Expression, OutermostLoop);
+  return SE->isLoopInvariant(Expression, LoopNest->getOutermostLoop());
 }
 
 

diff  --git a/llvm/lib/Analysis/ScalarEvolution.cpp b/llvm/lib/Analysis/ScalarEvolution.cpp
index 13591c0638181..57d1366b4066f 100644
--- a/llvm/lib/Analysis/ScalarEvolution.cpp
+++ b/llvm/lib/Analysis/ScalarEvolution.cpp
@@ -8085,9 +8085,7 @@ void ScalarEvolution::forgetLoop(const Loop *L) {
 }
 
 void ScalarEvolution::forgetTopmostLoop(const Loop *L) {
-  while (Loop *Parent = L->getParentLoop())
-    L = Parent;
-  forgetLoop(L);
+  forgetLoop(L->getOutermostLoop());
 }
 
 void ScalarEvolution::forgetValue(Value *V) {

diff  --git a/llvm/lib/Transforms/Utils/LoopUtils.cpp b/llvm/lib/Transforms/Utils/LoopUtils.cpp
index c5582fb90bbfe..965b35a50978b 100644
--- a/llvm/lib/Transforms/Utils/LoopUtils.cpp
+++ b/llvm/lib/Transforms/Utils/LoopUtils.cpp
@@ -686,18 +686,12 @@ void llvm::deleteDeadLoop(Loop *L, DominatorTree *DT, ScalarEvolution *SE,
   }
 }
 
-static Loop *getOutermostLoop(Loop *L) {
-  while (Loop *Parent = L->getParentLoop())
-    L = Parent;
-  return L;
-}
-
 void llvm::breakLoopBackedge(Loop *L, DominatorTree &DT, ScalarEvolution &SE,
                              LoopInfo &LI, MemorySSA *MSSA) {
   auto *Latch = L->getLoopLatch();
   assert(Latch && "multiple latches not yet supported");
   auto *Header = L->getHeader();
-  Loop *OutermostLoop = getOutermostLoop(L);
+  Loop *OutermostLoop = L->getOutermostLoop();
 
   SE.forgetLoop(L);