3 files changed, 30 insertions, 16 deletions
diff --git a/include/llvm/Transforms/Utils/LoopUtils.h b/include/llvm/Transforms/Utils/LoopUtils.h
index 5864e22e13..64e18ca1b6 100644
--- a/include/llvm/Transforms/Utils/LoopUtils.h
+++ b/include/llvm/Transforms/Utils/LoopUtils.h
@@ -47,6 +47,17 @@ bool simplifyLoop(Loop *L, DominatorTree *DT, LoopInfo *LI, Pass *PP,
 /// Returns true if any modifications are made to the loop.
 bool formLCSSA(Loop &L, DominatorTree &DT, ScalarEvolution *SE = 0);
 
+/// \brief Put a loop nest into LCSSA form.
+///
+/// This recursively forms LCSSA for a loop nest.
+///
+/// LoopInfo and DominatorTree are required and preserved.
+///
+/// If ScalarEvolution is passed in, it will be preserved.
+///
+/// Returns true if any modifications are made to the loop.
+bool formLCSSARecursively(Loop &L, DominatorTree &DT, ScalarEvolution *SE = 0);
+
 }
 
 #endif
diff --git a/lib/Transforms/Utils/LCSSA.cpp b/lib/Transforms/Utils/LCSSA.cpp
index 546f4b160a..5959324da6 100644
--- a/lib/Transforms/Utils/LCSSA.cpp
+++ b/lib/Transforms/Utils/LCSSA.cpp
@@ -226,6 +226,19 @@ bool llvm::formLCSSA(Loop &L, DominatorTree &DT, ScalarEvolution *SE) {
   return Changed;
 }
 
+/// Process a loop nest depth first.
+bool llvm::formLCSSARecursively(Loop &L, DominatorTree &DT,
+                                ScalarEvolution *SE) {
+  bool Changed = false;
+
+  // Recurse depth-first through inner loops.
+  for (Loop::iterator LI = L.begin(), LE = L.end(); LI != LE; ++LI)
+    Changed |= formLCSSARecursively(**LI, DT, SE);
+
+  Changed |= formLCSSA(L, DT, SE);
+  return Changed;
+}
+
 namespace {
 struct LCSSA : public FunctionPass {
   static char ID; // Pass identification, replacement for typeid
@@ -278,20 +291,8 @@ bool LCSSA::runOnFunction(Function &F) {
 
   // Simplify each loop nest in the function.
   for (LoopInfo::iterator I = LI->begin(), E = LI->end(); I != E; ++I)
-    Changed |= processLoop(**I);
-
-  return Changed;
-}
-
-/// Process a loop nest depth first.
-bool LCSSA::processLoop(Loop &L) {
-  bool Changed = false;
-
-  // Recurse depth-first through inner loops.
-  for (Loop::iterator LI = L.begin(), LE = L.end(); LI != LE; ++LI)
-    Changed |= processLoop(**LI);
+    Changed |= formLCSSARecursively(**I, *DT, SE);
 
-  Changed |= formLCSSA(L, *DT, SE);
   return Changed;
 }
 
diff --git a/lib/Transforms/Utils/LoopUnroll.cpp b/lib/Transforms/Utils/LoopUnroll.cpp
index 3c43fbbe82..d2dfc20e4d 100644
--- a/lib/Transforms/Utils/LoopUnroll.cpp
+++ b/lib/Transforms/Utils/LoopUnroll.cpp
@@ -468,9 +468,11 @@ bool llvm::UnrollLoop(Loop *L, unsigned Count, unsigned TripCount,
   if (PP && DT) {
     if (!OuterL && !CompletelyUnroll)
       OuterL = L;
-    if (OuterL)
-      simplifyLoop(OuterL, DT, LI, PP, /*AliasAnalysis*/ 0,
-                   PP->getAnalysisIfAvailable<ScalarEvolution>());
+    if (OuterL) {
+      ScalarEvolution *SE = PP->getAnalysisIfAvailable<ScalarEvolution>();
+      simplifyLoop(OuterL, DT, LI, PP, /*AliasAnalysis*/ 0, SE);
+      formLCSSARecursively(*OuterL, *DT, SE);
+    }
   }
 
   return true;