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