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[NFC][InstCombine] `vector_reduce_xor(?ext(<n x i1>))` --> `?ext(vector_reduce_add(<n x i1>))` 

Instead of expanding it ourselves,
we can just forward to `?ext(vector_reduce_add(<n x i1>))`, as per alive2:
https://alive2.llvm.org/ce/z/ymz7zE (self)
https://alive2.llvm.org/ce/z/eKu2v2 (skipped zext)
https://alive2.llvm.org/ce/z/c3BXgc (skipped sext)
This commit is contained in:
Roman Lebedev 2021-08-07 15:59:21 +03:00
parent c6ff867f92
commit 0a241e90d4
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GPG Key ID: 083C3EBB4A1689E0
1 changed files with 4 additions and 7 deletions
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11
llvm/lib/Transforms/InstCombine/InstCombineCalls.cpp
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@ -2038,20 +2038,17 @@ Instruction *InstCombinerImpl::visitCallInst(CallInst &CI) {
if (IID == Intrinsic::vector_reduce_xor) {
// Exclusive disjunction reduction over the vector with
// (potentially-extended) i1 element type is actually a
// (potentially-extended) parity check:
// (potentially-extended) arithmetic `add` reduction over the original
// non-extended value:
// vector_reduce_xor(?ext(<n x i1>))
// -->
// ?ext(trunc(vector_reduce_and(<n x i1>) to i1))
// ?ext(vector_reduce_add(<n x i1>))
Value *Arg = II->getArgOperand(0);
Value *Vect;
if (match(Arg, m_ZExtOrSExtOrSelf(m_Value(Vect)))) {
if (auto *FTy = dyn_cast<FixedVectorType>(Vect->getType()))
if (FTy->getElementType() == Builder.getInt1Ty()) {
Value *V = Builder.CreateBitCast(
Vect, Builder.getIntNTy(FTy->getNumElements()));
Value *Res = Builder.CreateUnaryIntrinsic(Intrinsic::ctpop, V);
Res = Builder.CreateTrunc(Res,
IntegerType::get(Res->getContext(), 1));
Value *Res = Builder.CreateAddReduce(Vect);
if (Arg != Vect)
Res = Builder.CreateCast(cast<CastInst>(Arg)->getOpcode(), Res,
II->getType());