LatticeVal &V2State = getValueState(I.getOperand(1));
if (V1State.isOverdefined() || V2State.isOverdefined()) {
+ // If this is an AND or OR with 0 or -1, it doesn't matter that the other
+ // operand is overdefined.
+ if (I.getOpcode() == Instruction::And || I.getOpcode() == Instruction::Or) {
+ LatticeVal *NonOverdefVal = 0;
+ if (!V1State.isOverdefined()) {
+ NonOverdefVal = &V1State;
+ } else if (!V2State.isOverdefined()) {
+ NonOverdefVal = &V2State;
+ }
+
+ if (NonOverdefVal) {
+ if (NonOverdefVal->isUndefined()) {
+ // Could annihilate value.
+ if (I.getOpcode() == Instruction::And)
+ markConstant(IV, &I, Constant::getNullValue(I.getType()));
+ else
+ markConstant(IV, &I, ConstantInt::getAllOnesValue(I.getType()));
+ return;
+ } else {
+ if (I.getOpcode() == Instruction::And) {
+ if (NonOverdefVal->getConstant()->isNullValue()) {
+ markConstant(IV, &I, NonOverdefVal->getConstant());
+ return; // X or 0 = -1
+ }
+ } else {
+ if (ConstantIntegral *CI =
+ dyn_cast<ConstantIntegral>(NonOverdefVal->getConstant()))
+ if (CI->isAllOnesValue()) {
+ markConstant(IV, &I, NonOverdefVal->getConstant());
+ return; // X or -1 = -1
+ }
+ }
+ }
+ }
+ }
+
+
// If both operands are PHI nodes, it is possible that this instruction has
// a constant value, despite the fact that the PHI node doesn't. Check for
// this condition now.