[llvm] r209838 - implement missing SCEVDivision case

[Sebastian Pop]

Author: spop
Date: Thu May 29 14:44:09 2014
New Revision: 209838

URL: http://llvm.org/viewvc/llvm-project?rev=209838&view=rev
Log:
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.

Modified:
    llvm/trunk/lib/Analysis/ScalarEvolution.cpp

Modified: llvm/trunk/lib/Analysis/ScalarEvolution.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Analysis/ScalarEvolution.cpp?rev=209838&r1=209837&r2=209838&view=diff
==============================================================================
--- llvm/trunk/lib/Analysis/ScalarEvolution.cpp (original)
+++ llvm/trunk/lib/Analysis/ScalarEvolution.cpp Thu May 29 14:44:09 2014
@@ -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);