1 files changed, 51 insertions, 4 deletions

diff --git a/lib/Analysis/ScalarEvolution.cpp b/lib/Analysis/ScalarEvolution.cpp
index 6c91dca..70321fa 100644
--- a/lib/Analysis/ScalarEvolution.cpp
+++ b/lib/Analysis/ScalarEvolution.cpp
@@ -344,6 +344,24 @@ const Type *SCEVSDivExpr::getType() const {
   return LHS->getType();
 }
 
+// SCEVUDivs - Only allow the creation of one SCEVUDivExpr for any particular
+// input.  Don't use a SCEVHandle here, or else the object will never be
+// deleted!
+static ManagedStatic<std::map<std::pair<SCEV*, SCEV*>, 
+                     SCEVUDivExpr*> > SCEVUDivs;
+
+SCEVUDivExpr::~SCEVUDivExpr() {
+  SCEVUDivs->erase(std::make_pair(LHS, RHS));
+}
+
+void SCEVUDivExpr::print(std::ostream &OS) const {
+  OS << "(" << *LHS << " /u " << *RHS << ")";
+}
+
+const Type *SCEVUDivExpr::getType() const {
+  return LHS->getType();
+}
+
 // SCEVAddRecExprs - Only allow the creation of one SCEVAddRecExpr for any
 // particular input.  Don't use a SCEVHandle here, or else the object will never
 // be deleted!
@@ -573,7 +591,7 @@ SCEVHandle SCEVAddRecExpr::evaluateAtIteration(SCEVHandle It,
   for (unsigned i = 1, e = getNumOperands(); i != e; ++i) {
     SCEVHandle BC = PartialFact(It, i, SE);
     Divisor *= i;
-    SCEVHandle Val = SE.getSDivExpr(SE.getMulExpr(BC, getOperand(i)),
+    SCEVHandle Val = SE.getUDivExpr(SE.getMulExpr(BC, getOperand(i)),
                                     SE.getIntegerSCEV(Divisor,Ty));
     Result = SE.getAddExpr(Result, Val);
   }
@@ -1037,7 +1055,8 @@ SCEVHandle ScalarEvolution::getMulExpr(std::vector<SCEVHandle> &Ops) {
   return Result;
 }
 
-SCEVHandle ScalarEvolution::getSDivExpr(const SCEVHandle &LHS, const SCEVHandle &RHS) {
+SCEVHandle ScalarEvolution::getSDivExpr(const SCEVHandle &LHS,
+                                        const SCEVHandle &RHS) {
   if (SCEVConstant *RHSC = dyn_cast<SCEVConstant>(RHS)) {
     if (RHSC->getValue()->equalsInt(1))
       return LHS;                            // X sdiv 1 --> x
@@ -1058,6 +1077,26 @@ SCEVHandle ScalarEvolution::getSDivExpr(const SCEVHandle &LHS, const SCEVHandle
   return Result;
 }
 
+SCEVHandle ScalarEvolution::getUDivExpr(const SCEVHandle &LHS,
+                                        const SCEVHandle &RHS) {
+  if (SCEVConstant *RHSC = dyn_cast<SCEVConstant>(RHS)) {
+    if (RHSC->getValue()->equalsInt(1))
+      return LHS;                            // X udiv 1 --> x
+
+    if (SCEVConstant *LHSC = dyn_cast<SCEVConstant>(LHS)) {
+      Constant *LHSCV = LHSC->getValue();
+      Constant *RHSCV = RHSC->getValue();
+      return getUnknown(ConstantExpr::getUDiv(LHSCV, RHSCV));
+    }
+  }
+
+  // FIXME: implement folding of (X*4)/4 when we know X*4 doesn't overflow.
+
+  SCEVUDivExpr *&Result = (*SCEVUDivs)[std::make_pair(LHS, RHS)];
+  if (Result == 0) Result = new SCEVUDivExpr(LHS, RHS);
+  return Result;
+}
+
 
 /// SCEVAddRecExpr::get - Get a add recurrence expression for the
 /// specified loop.  Simplify the expression as much as possible.
@@ -1484,8 +1523,6 @@ SCEVHandle ScalarEvolutionsImpl::createSCEV(Value *V) {
     case Instruction::SDiv:
       return SE.getSDivExpr(getSCEV(I->getOperand(0)),
                             getSCEV(I->getOperand(1)));
-      break;
-
     case Instruction::Sub:
       return SE.getMinusSCEV(getSCEV(I->getOperand(0)),
                              getSCEV(I->getOperand(1)));
@@ -2145,6 +2182,16 @@ SCEVHandle ScalarEvolutionsImpl::getSCEVAtScope(SCEV *V, const Loop *L) {
     return SE.getSDivExpr(LHS, RHS);
   }
 
+  if (SCEVUDivExpr *Div = dyn_cast<SCEVUDivExpr>(V)) {
+    SCEVHandle LHS = getSCEVAtScope(Div->getLHS(), L);
+    if (LHS == UnknownValue) return LHS;
+    SCEVHandle RHS = getSCEVAtScope(Div->getRHS(), L);
+    if (RHS == UnknownValue) return RHS;
+    if (LHS == Div->getLHS() && RHS == Div->getRHS())
+      return Div;   // must be loop invariant
+    return SE.getUDivExpr(LHS, RHS);
+  }
+
   // If this is a loop recurrence for a loop that does not contain L, then we
   // are dealing with the final value computed by the loop.
   if (SCEVAddRecExpr *AddRec = dyn_cast<SCEVAddRecExpr>(V)) {