Transforms/InstCombine/InstCombineVectorOps.cpp

325 /// elements from either LHS or RHS, return the shuffle mask and true.
327 static bool CollectSingleShuffleElements(Value *V, Value *LHS, Value *RHS,
329   assert(V->getType() == LHS->getType() && V->getType() == RHS->getType() &&
338   if (V == LHS) {
364       if (CollectSingleShuffleElements(VecOp, LHS, RHS, Mask)) {
375         // This must be extracting from either LHS or RHS.
376         if (EI->getOperand(0) == LHS || EI->getOperand(0) == RHS) {
379           if (CollectSingleShuffleElements(VecOp, LHS, RHS, Mask)) {
381             if (EI->getOperand(0) == LHS) {
404 /// that computes V and the LHS value of the shuffle.
511         Value *LHS = CollectShuffleElements(&IE, Mask, RHS);
512         if (RHS == 0) RHS = UndefValue::get(LHS->getType());
513         // We now have a shuffle of LHS, RHS, Mask.
514         return new ShuffleVectorInst(LHS, RHS, ConstantVector::get(Mask));
781   Value *LHS = SVI.getOperand(0);
798     LHS = SVI.getOperand(0);
803   unsigned LHSWidth = cast<VectorType>(LHS->getType())->getNumElements();
807   if (LHS == RHS || isa<UndefValue>(LHS)) {
808     if (isa<UndefValue>(LHS) && LHS == RHS) {
811                       ? LHS : UndefValue::get(SVI.getType());
815     // Remap any references to RHS to use LHS.
824           (Mask[i] <  (int)e && isa<UndefValue>(LHS))) {
828         Mask[i] = Mask[i] % e;  // Force to LHS.
836     LHS = SVI.getOperand(0);
842     // Analyze the shuffle, are the LHS or RHS and identity shuffles?
847       // Is this an identity shuffle of the LHS value?
855     if (isLHSID) return ReplaceInstUsesWith(SVI, LHS);
859   if (isa<UndefValue>(RHS) && CanEvaluateShuffled(LHS, Mask)) {
860     Value *V = EvaluateInDifferentElementOrder(LHS, Mask);
864   // If the LHS is a shufflevector itself, see if we can combine it with this
907   ShuffleVectorInst* LHSShuffle = dyn_cast<ShuffleVectorInst>(LHS);
932   Value* newLHS = LHS;
955   if (newLHS == LHS && newRHS == RHS)
960   if (newLHS != LHS)
965   unsigned newLHSWidth = (newLHS != LHS) ? LHSOp0Width : LHSWidth;
979       // If LHS is going to be replaced (case 1, 2, or 4), calculate the
981       if (newLHS != LHS) {
1010       // If LHS's width is changed, shift the mask value accordingly.