Tighten the API for ScalarEvolutionNormalization

llvm-svn: 300331

3 files changed, 40 insertions, 16 deletions

diff --git a/llvm/lib/Analysis/IVUsers.cpp b/llvm/lib/Analysis/IVUsers.cpp
index de38cf8366c..fde805a5fde 100644
--- a/llvm/lib/Analysis/IVUsers.cpp
+++ b/llvm/lib/Analysis/IVUsers.cpp
@@ -270,17 +270,15 @@ bool IVUsers::AddUsersImpl(Instruction *I,
         return Result;
       };
 
-      ISE = TransformForPostIncUse(Normalize, ISE,
-                                   Optional<NormalizePredTy>(NormalizePred),
-                                   NewUse.PostIncLoops, *SE);
+      ISE = normalizeForPostIncUseIf(ISE, NormalizePred, *SE);
 
       // PostIncNormalization effectively simplifies the expression under
       // pre-increment assumptions. Those assumptions (no wrapping) might not
       // hold for the post-inc value. Catch such cases by making sure the
       // transformation is invertible.
       if (OriginalISE != ISE) {
-        const SCEV *DenormalizedISE = TransformForPostIncUse(
-            Denormalize, ISE, None, NewUse.PostIncLoops, *SE);
+        const SCEV *DenormalizedISE =
+            denormalizeForPostIncUse(ISE, NewUse.PostIncLoops, *SE);
 
         // If we normalized the expression, but denormalization doesn't give the
         // original one, discard this user.
@@ -398,9 +396,8 @@ const SCEV *IVUsers::getReplacementExpr(const IVStrideUse &IU) const {
 
 /// getExpr - Return the expression for the use.
 const SCEV *IVUsers::getExpr(const IVStrideUse &IU) const {
-  return TransformForPostIncUse(
-      Normalize, getReplacementExpr(IU), None,
-      const_cast<PostIncLoopSet &>(IU.getPostIncLoops()), *SE);
+  return normalizeForPostIncUse(getReplacementExpr(IU), IU.getPostIncLoops(),
+                                *SE);
 }
 
 static const SCEVAddRecExpr *findAddRecForLoop(const SCEV *S, const Loop *L) {
diff --git a/llvm/lib/Analysis/ScalarEvolutionExpander.cpp b/llvm/lib/Analysis/ScalarEvolutionExpander.cpp
index 66df34dbe7f..6dd10441c4c 100644
--- a/llvm/lib/Analysis/ScalarEvolutionExpander.cpp
+++ b/llvm/lib/Analysis/ScalarEvolutionExpander.cpp
@@ -1268,8 +1268,7 @@ Value *SCEVExpander::expandAddRecExprLiterally(const SCEVAddRecExpr *S) {
   if (PostIncLoops.count(L)) {
     PostIncLoopSet Loops;
     Loops.insert(L);
-    Normalized = cast<SCEVAddRecExpr>(
-        TransformForPostIncUse(Normalize, S, None, Loops, SE));
+    Normalized = cast<SCEVAddRecExpr>(normalizeForPostIncUse(S, Loops, SE));
   }
 
   // Strip off any non-loop-dominating component from the addrec start.
diff --git a/llvm/lib/Analysis/ScalarEvolutionNormalization.cpp b/llvm/lib/Analysis/ScalarEvolutionNormalization.cpp
index becc4bb6010..89237273d01 100644
--- a/llvm/lib/Analysis/ScalarEvolutionNormalization.cpp
+++ b/llvm/lib/Analysis/ScalarEvolutionNormalization.cpp
@@ -19,19 +19,29 @@ using namespace llvm;
 
 namespace {
 
+/// TransformKind - Different types of transformations that
+/// TransformForPostIncUse can do.
+enum TransformKind {
+  /// Normalize - Normalize according to the given loops.
+  Normalize,
+  /// Denormalize - Perform the inverse transform on the expression with the
+  /// given loop set.
+  Denormalize
+};
+
 /// Hold the state used during post-inc expression transformation, including a
 /// map of transformed expressions.
 class PostIncTransform {
   TransformKind Kind;
   Optional<NormalizePredTy> Pred;
-  PostIncLoopSet &Loops;
+  const PostIncLoopSet &Loops;
   ScalarEvolution &SE;
 
   DenseMap<const SCEV*, const SCEV*> Transformed;
 
 public:
   PostIncTransform(TransformKind kind, Optional<NormalizePredTy> Pred,
-                   PostIncLoopSet &loops, ScalarEvolution &se)
+                   const PostIncLoopSet &loops, ScalarEvolution &se)
       : Kind(kind), Pred(Pred), Loops(loops), SE(se) {}
 
   const SCEV *TransformSubExpr(const SCEV *S);
@@ -160,10 +170,28 @@ const SCEV *PostIncTransform::TransformSubExpr(const SCEV *S) {
 
 /// Top level driver for transforming an expression DAG into its requested
 /// post-inc form (either "Normalized" or "Denormalized").
-const SCEV *llvm::TransformForPostIncUse(TransformKind Kind, const SCEV *S,
-                                         Optional<NormalizePredTy> Pred,
-                                         PostIncLoopSet &Loops,
-                                         ScalarEvolution &SE) {
+static const SCEV *TransformForPostIncUse(TransformKind Kind, const SCEV *S,
+                                          Optional<NormalizePredTy> Pred,
+                                          const PostIncLoopSet &Loops,
+                                          ScalarEvolution &SE) {
   PostIncTransform Transform(Kind, Pred, Loops, SE);
   return Transform.TransformSubExpr(S);
 }
+
+const SCEV *llvm::normalizeForPostIncUse(const SCEV *S,
+                                         const PostIncLoopSet &Loops,
+                                         ScalarEvolution &SE) {
+  return TransformForPostIncUse(Normalize, S, None, Loops, SE);
+}
+
+const SCEV *llvm::normalizeForPostIncUseIf(const SCEV *S, NormalizePredTy Pred,
+                                           ScalarEvolution &SE) {
+  PostIncLoopSet Empty;
+  return TransformForPostIncUse(Normalize, S, Pred, Empty, SE);
+}
+
+const SCEV *llvm::denormalizeForPostIncUse(const SCEV *S,
+                                           const PostIncLoopSet &Loops,
+                                           ScalarEvolution &SE) {
+  return TransformForPostIncUse(Denormalize, S, None, Loops, SE);
+}