================
@@ -428,6 +431,85 @@ Value *VPInstruction::generatePerPart(VPTransformState
&State, unsigned Part) {
{PredTy, ScalarTC->getType()},
{VIVElem0, ScalarTC}, nullptr, Name);
}
+ case VPInstruction::AliasLaneMask: {
+ // Given a pointer A that is being stored to, and pointer B that is being
+ // read from, both with unknown lengths, create a mask that disables
+ // elements which could overlap across a loop iteration. For example, if A
+ // is X and B is X + 2 with VF being 4, only the final two elements of the
+ // loaded vector can be stored since they don't overlap with the stored
+ // vector. %b.vec = load %b ; = [s, t, u, v]
+ // [...]
+ // store %a, %b.vec ; only u and v can be stored as their addresses don't
+ // overlap with %a + (VF - 1)
+ Value *ReadPtr = State.get(getOperand(0), VPIteration(Part, 0));
+ Value *StorePtr = State.get(getOperand(1), VPIteration(Part, 0));
+ unsigned ElementSize = 0;
+
+ // We expect the operands to the alias mask to be ptrtoint. Sometimes it's
+ // an add of a ptrtoint.
+ auto *ReadInsn = cast<Instruction>(ReadPtr);
+ auto *ReadCast = dyn_cast<CastInst>(ReadPtr);
+ if (ReadInsn->getOpcode() == Instruction::Add)
+ ReadCast = dyn_cast<CastInst>(ReadInsn->getOperand(0));
+
+ if (ReadCast && ReadCast->getOpcode() == Instruction::PtrToInt) {
+ Value *Ptr = ReadCast->getOperand(0);
+ for (auto *Use : Ptr->users()) {
----------------
fhahn wrote:
Execution should avoid inspecting the original IR or generated IR values.
can the necessary info be encoded in the recipe?
https://github.com/llvm/llvm-project/pull/100579
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