Rename forgetLoopBackedgeTakenCount to forgetLoop, because it

clears out more information than just the stored backedge taken count.

llvm-svn: 85664

llvm/include/llvm/Analysis/ScalarEvolution.h

@@ -563,11 +563,10 @@ namespace llvm {
     /// has an analyzable loop-invariant backedge-taken count.
     bool hasLoopInvariantBackedgeTakenCount(const Loop *L);
 
-    /// forgetLoopBackedgeTakenCount - This method should be called by the
-    /// client when it has changed a loop in a way that may effect
-    /// ScalarEvolution's ability to compute a trip count, or if the loop
-    /// is deleted.
-    void forgetLoopBackedgeTakenCount(const Loop *L);
+    /// forgetLoop - This method should be called by the client when it has
+    /// changed a loop in a way that may effect ScalarEvolution's ability to
+    /// compute a trip count, or if the loop is deleted.
+    void forgetLoop(const Loop *L);
 
     /// GetMinTrailingZeros - Determine the minimum number of zero bits that S
     /// is guaranteed to end in (at every loop iteration).  It is, at the same

llvm/lib/Analysis/ScalarEvolution.cpp

@@ -3265,9 +3265,8 @@ ScalarEvolution::getBackedgeTakenInfo(const Loop *L) {
     // Now that we know more about the trip count for this loop, forget any
     // existing SCEV values for PHI nodes in this loop since they are only
     // conservative estimates made without the benefit of trip count
-    // information. This is similar to the code in
-    // forgetLoopBackedgeTakenCount, except that it handles SCEVUnknown PHI
-    // nodes specially.
+    // information. This is similar to the code in forgetLoop, except that
+    // it handles SCEVUnknown PHI nodes specially.
     if (ItCount.hasAnyInfo()) {
       SmallVector<Instruction *, 16> Worklist;
       PushLoopPHIs(L, Worklist);
@@ -3301,13 +3300,14 @@ ScalarEvolution::getBackedgeTakenInfo(const Loop *L) {
   return Pair.first->second;
 }
 
-/// forgetLoopBackedgeTakenCount - This method should be called by the
-/// client when it has changed a loop in a way that may effect
-/// ScalarEvolution's ability to compute a trip count, or if the loop
-/// is deleted.
-void ScalarEvolution::forgetLoopBackedgeTakenCount(const Loop *L) {
+/// forgetLoop - This method should be called by the client when it has
+/// changed a loop in a way that may effect ScalarEvolution's ability to
+/// compute a trip count, or if the loop is deleted.
+void ScalarEvolution::forgetLoop(const Loop *L) {
+  // Drop any stored trip count value.
   BackedgeTakenCounts.erase(L);
 
+  // Drop information about expressions based on loop-header PHIs.
   SmallVector<Instruction *, 16> Worklist;
   PushLoopPHIs(L, Worklist);
 

llvm/lib/Transforms/Scalar/IndVarSimplify.cpp

@@ -322,7 +322,7 @@ void IndVarSimplify::RewriteNonIntegerIVs(Loop *L) {
   // may not have been able to compute a trip count. Now that we've done some
   // re-writing, the trip count may be computable.
   if (Changed)
-    SE->forgetLoopBackedgeTakenCount(L);
+    SE->forgetLoop(L);
 }
 
 bool IndVarSimplify::runOnLoop(Loop *L, LPPassManager &LPM) {

llvm/lib/Transforms/Scalar/LoopDeletion.cpp

@@ -161,7 +161,7 @@ bool LoopDeletion::runOnLoop(Loop* L, LPPassManager& LPM) {
   // Tell ScalarEvolution that the loop is deleted. Do this before
   // deleting the loop so that ScalarEvolution can look at the loop
   // to determine what it needs to clean up.
-  SE.forgetLoopBackedgeTakenCount(L);
+  SE.forgetLoop(L);
 
   // Connect the preheader directly to the exit block.
   TerminatorInst* TI = preheader->getTerminator();

llvm/lib/Transforms/Scalar/LoopRotation.cpp

@@ -157,7 +157,7 @@ bool LoopRotate::rotateLoop(Loop *Lp, LPPassManager &LPM) {
   // Anything ScalarEvolution may know about this loop or the PHI nodes
   // in its header will soon be invalidated.
   if (ScalarEvolution *SE = getAnalysisIfAvailable<ScalarEvolution>())
-    SE->forgetLoopBackedgeTakenCount(L);
+    SE->forgetLoop(L);
 
   // Find new Loop header. NewHeader is a Header's one and only successor
   // that is inside loop.  Header's other successor is outside the