From 6ce2471806316ae9e1c7715f703c380d4f4311b6 Mon Sep 17 00:00:00 2001 From: Nick Lewycky Date: Wed, 1 Aug 2012 09:14:36 +0000 Subject: 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 --- lib/Analysis/ScalarEvolution.cpp | 6 ++++++ 1 file changed, 6 insertions(+) (limited to 'lib/Analysis') diff --git a/lib/Analysis/ScalarEvolution.cpp b/lib/Analysis/ScalarEvolution.cpp index f0f3b1cb66..a654648578 100644 --- a/lib/Analysis/ScalarEvolution.cpp +++ b/lib/Analysis/ScalarEvolution.cpp @@ -5370,6 +5370,12 @@ SolveQuadraticEquation(const SCEVAddRecExpr *AddRec, ScalarEvolution &SE) { 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()); -- cgit v1.2.3