diff options
| -rw-r--r-- | llvm/lib/Analysis/ScalarEvolution.cpp | 71 |
1 files changed, 34 insertions, 37 deletions
diff --git a/llvm/lib/Analysis/ScalarEvolution.cpp b/llvm/lib/Analysis/ScalarEvolution.cpp index 92634e3d2cd..76da5bd057f 100644 --- a/llvm/lib/Analysis/ScalarEvolution.cpp +++ b/llvm/lib/Analysis/ScalarEvolution.cpp @@ -7377,48 +7377,45 @@ SolveQuadraticEquation(const SCEVAddRecExpr *AddRec, ScalarEvolution &SE) { const APInt &N = NC->getAPInt(); APInt Two(BitWidth, 2); - { - using namespace APIntOps; - const APInt& C = L; - // Convert from chrec coefficients to polynomial coefficients AX^2+BX+C - // The B coefficient is M-N/2 - APInt B(M); - B -= N.sdiv(Two); - - // The A coefficient is N/2 - APInt A(N.sdiv(Two)); - - // Compute the B^2-4ac term. - APInt SqrtTerm(B); - SqrtTerm *= B; - SqrtTerm -= 4 * (A * C); - - if (SqrtTerm.isNegative()) { - // The loop is provably infinite. - return None; - } + const APInt& C = L; + // Convert from chrec coefficients to polynomial coefficients AX^2+BX+C + // The B coefficient is M-N/2 + APInt B(M); + B -= N.sdiv(Two); + + // The A coefficient is N/2 + APInt A(N.sdiv(Two)); + + // Compute the B^2-4ac term. + APInt SqrtTerm(B); + SqrtTerm *= B; + SqrtTerm -= 4 * (A * C); + + if (SqrtTerm.isNegative()) { + // The loop is provably infinite. + return None; + } - // Compute sqrt(B^2-4ac). This is guaranteed to be the nearest - // integer value or else APInt::sqrt() will assert. - APInt SqrtVal(SqrtTerm.sqrt()); + // Compute sqrt(B^2-4ac). This is guaranteed to be the nearest + // integer value or else APInt::sqrt() will assert. + APInt SqrtVal(SqrtTerm.sqrt()); - // Compute the two solutions for the quadratic formula. - // The divisions must be performed as signed divisions. - APInt NegB(-B); - APInt TwoA(A << 1); - if (TwoA.isMinValue()) - return None; + // Compute the two solutions for the quadratic formula. + // The divisions must be performed as signed divisions. + APInt NegB(-B); + APInt TwoA(A << 1); + if (TwoA.isMinValue()) + return None; - LLVMContext &Context = SE.getContext(); + LLVMContext &Context = SE.getContext(); - ConstantInt *Solution1 = - ConstantInt::get(Context, (NegB + SqrtVal).sdiv(TwoA)); - ConstantInt *Solution2 = - ConstantInt::get(Context, (NegB - SqrtVal).sdiv(TwoA)); + ConstantInt *Solution1 = + ConstantInt::get(Context, (NegB + SqrtVal).sdiv(TwoA)); + ConstantInt *Solution2 = + ConstantInt::get(Context, (NegB - SqrtVal).sdiv(TwoA)); - return std::make_pair(cast<SCEVConstant>(SE.getConstant(Solution1)), - cast<SCEVConstant>(SE.getConstant(Solution2))); - } // end APIntOps namespace + return std::make_pair(cast<SCEVConstant>(SE.getConstant(Solution1)), + cast<SCEVConstant>(SE.getConstant(Solution2))); } ScalarEvolution::ExitLimit |
