implement missing SCEVDivision case

without this case we would end on an infinite recursion: the remainder is zero,
so Numerator - Remainder is equal to Numerator and so we would recursively ask
for the division of Numerator by Denominator.

llvm-svn: 209838

1 files changed, 9 insertions, 0 deletions

diff --git a/llvm/lib/Analysis/ScalarEvolution.cpp b/llvm/lib/Analysis/ScalarEvolution.cpp
index 935d4158c39..bc9f45b2043 100644
--- a/llvm/lib/Analysis/ScalarEvolution.cpp
+++ b/llvm/lib/Analysis/ScalarEvolution.cpp
@@ -7216,6 +7216,15 @@ public:
         cast<SCEVConstant>(Zero)->getValue();
     Remainder = SCEVParameterRewriter::rewrite(Numerator, SE, RewriteMap, true);
 
+    if (Remainder->isZero()) {
+      // The Quotient is obtained by replacing Denominator by 1 in Numerator.
+      RewriteMap[cast<SCEVUnknown>(Denominator)->getValue()] =
+          cast<SCEVConstant>(One)->getValue();
+      Quotient =
+          SCEVParameterRewriter::rewrite(Numerator, SE, RewriteMap, true);
+      return;
+    }
+
     // Quotient is (Numerator - Remainder) divided by Denominator.
     const SCEV *Q, *R;
     const SCEV *Diff = SE.getMinusSCEV(Numerator, Remainder);