Stay rational; don't assert trying to take the square root of a negative value.
If it's negative, the loop is already proven to be infinite. Fixes PR13489!
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@161107 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Analysis/ScalarEvolution.cpp b/lib/Analysis/ScalarEvolution.cpp
index f0f3b1c..a654648 100644
--- a/lib/Analysis/ScalarEvolution.cpp
+++ b/lib/Analysis/ScalarEvolution.cpp
@@ -5370,6 +5370,12 @@
SqrtTerm *= B;
SqrtTerm -= Four * (A * C);
+ if (SqrtTerm.isNegative()) {
+ // The loop is provably infinite.
+ const SCEV *CNC = SE.getCouldNotCompute();
+ return std::make_pair(CNC, CNC);
+ }
+
// Compute sqrt(B^2-4ac). This is guaranteed to be the nearest
// integer value or else APInt::sqrt() will assert.
APInt SqrtVal(SqrtTerm.sqrt());