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[X86][InstCombine] Tidyup VPERMILVAR -> shufflevector conversion to helper function. NFCI. 

llvm-svn: 267352
This commit is contained in:
Simon Pilgrim 2016-04-24 17:23:46 +00:00
parent c0c56e747a
commit 2f6097d113
1 changed files with 47 additions and 36 deletions
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83
llvm/lib/Transforms/InstCombine/InstCombineCalls.cpp
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@ -630,6 +630,49 @@ static Value *simplifyX86pshufb(const IntrinsicInst &II,
return Builder.CreateShuffleVector(V1, V2, ShuffleMask);
}
/// Attempt to convert vpermilvar* to shufflevector if the mask is constant.
static Value *simplifyX86vpermilvar(const IntrinsicInst &II,
InstCombiner::BuilderTy &Builder) {
Value *V = II.getArgOperand(1);
unsigned Size = cast<VectorType>(V->getType())->getNumElements();
assert(Size == 8 || Size == 4 || Size == 2);
uint32_t Indexes[8];
if (auto C = dyn_cast<ConstantDataVector>(V)) {
// The intrinsics only read one or two bits, clear the rest.
for (unsigned I = 0; I < Size; ++I) {
uint32_t Index = C->getElementAsInteger(I) & 0x3;
// The PD variants uses bit 1 to select per-lane element index, so
// shift down to convert to generic shuffle mask index.
if (II.getIntrinsicID() == Intrinsic::x86_avx_vpermilvar_pd ||
II.getIntrinsicID() == Intrinsic::x86_avx_vpermilvar_pd_256)
Index >>= 1;
Indexes[I] = Index;
}
} else if (isa<ConstantAggregateZero>(V)) {
for (unsigned I = 0; I < Size; ++I)
Indexes[I] = 0;
} else {
return nullptr;
}
// The _256 variants are a bit trickier since the mask bits always index
// into the corresponding 128 half. In order to convert to a generic
// shuffle, we have to make that explicit.
if (II.getIntrinsicID() == Intrinsic::x86_avx_vpermilvar_ps_256 ||
II.getIntrinsicID() == Intrinsic::x86_avx_vpermilvar_pd_256) {
for (unsigned I = Size / 2; I < Size; ++I)
Indexes[I] += Size / 2;
}
auto ShuffleMask =
ConstantDataVector::get(V->getContext(), makeArrayRef(Indexes, Size));
auto V1 = II.getArgOperand(0);
auto V2 = UndefValue::get(V1->getType());
return Builder.CreateShuffleVector(V1, V2, ShuffleMask);
}
/// The shuffle mask for a perm2*128 selects any two halves of two 256-bit
/// source vectors, unless a zero bit is set. If a zero bit is set,
/// then ignore that half of the mask and clear that half of the vector.
@ -1635,42 +1678,10 @@ Instruction *InstCombiner::visitCallInst(CallInst &CI) {
case Intrinsic::x86_avx_vpermilvar_ps:
case Intrinsic::x86_avx_vpermilvar_ps_256:
case Intrinsic::x86_avx_vpermilvar_pd:
case Intrinsic::x86_avx_vpermilvar_pd_256: {
// Convert vpermil* to shufflevector if the mask is constant.
Value *V = II->getArgOperand(1);
unsigned Size = cast<VectorType>(V->getType())->getNumElements();
assert(Size == 8 || Size == 4 || Size == 2);
uint32_t Indexes[8];
if (auto C = dyn_cast<ConstantDataVector>(V)) {
// The intrinsics only read one or two bits, clear the rest.
for (unsigned I = 0; I < Size; ++I) {
uint32_t Index = C->getElementAsInteger(I) & 0x3;
if (II->getIntrinsicID() == Intrinsic::x86_avx_vpermilvar_pd ||
II->getIntrinsicID() == Intrinsic::x86_avx_vpermilvar_pd_256)
Index >>= 1;
Indexes[I] = Index;
}
} else if (isa<ConstantAggregateZero>(V)) {
for (unsigned I = 0; I < Size; ++I)
Indexes[I] = 0;
} else {
break;
}
// The _256 variants are a bit trickier since the mask bits always index
// into the corresponding 128 half. In order to convert to a generic
// shuffle, we have to make that explicit.
if (II->getIntrinsicID() == Intrinsic::x86_avx_vpermilvar_ps_256 ||
II->getIntrinsicID() == Intrinsic::x86_avx_vpermilvar_pd_256) {
for (unsigned I = Size / 2; I < Size; ++I)
Indexes[I] += Size / 2;
}
auto NewC =
ConstantDataVector::get(V->getContext(), makeArrayRef(Indexes, Size));
auto V1 = II->getArgOperand(0);
auto V2 = UndefValue::get(V1->getType());
auto Shuffle = Builder->CreateShuffleVector(V1, V2, NewC);
return replaceInstUsesWith(CI, Shuffle);
}
case Intrinsic::x86_avx_vpermilvar_pd_256:
if (Value *V = simplifyX86vpermilvar(*II, *Builder))
return replaceInstUsesWith(*II, V);
break;
case Intrinsic::x86_avx_vperm2f128_pd_256:
case Intrinsic::x86_avx_vperm2f128_ps_256: