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Differential D41794 Diff 129789 lib/Target/X86/X86ISelLowering.cpp

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lib/Target/X86/X86ISelLowering.cpp

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Show First 20 Lines • Show All 10,741 Lines • ▼ Show 20 Lines return DAG.getVectorShuffle(
VT, DL, DAG.getNode(NumLoInputs == 0 ? X86ISD::UNPCKH : X86ISD::UNPCKL, VT, DL, DAG.getNode(NumLoInputs == 0 ? X86ISD::UNPCKH : X86ISD::UNPCKL,
DL, VT, V1, V2), DL, VT, V1, V2),
DAG.getUNDEF(VT), PermMask); DAG.getUNDEF(VT), PermMask);
} }
return SDValue(); return SDValue();
} }
// Attempt to lower a shuffle where one lane comes from V1 and the other
// lane comes from V2 and the lanes do the same operation. We can create
// a new V1 with the lower lane of V1 and the lower lane of V2. And a new
// V2 with the upper lane of V1 and the upper lane of V2 and then do a
// repeated lane shuffle.
static SDValue lowerVectorShuffleSplitLowHigh(const SDLoc &DL,
MVT VT, SDValue V1,
SDValue V2,
ArrayRef<int> Mask,
SelectionDAG &DAG) {
int Size = Mask.size();
SmallVector<int, 8> RepeatMask(Size, -1);
RKSimonUnsubmitted
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Should't RepeatMask be just LaneSize wide?

RKSimon: Should't RepeatMask be just LaneSize wide?
craig.topperAuthorUnsubmitted
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Yes it should.

craig.topper: Yes it should.
int LaneSize = 128 / VT.getScalarSizeInBits();
for (int i = 0; i != Size; ++i) {
int M = Mask[i];
if (M < 0)
continue;
// Make sure the element comes from the same source as the half.
if ((M / Size) != (i / LaneSize))
return SDValue();
int LocalM = M % Size;
if (RepeatMask[i % LaneSize] < 0)
RepeatMask[i % LaneSize] = LocalM;
else if (RepeatMask[i % LaneSize] != LocalM)
return SDValue();
}
SmallVector<int, 8> PermuteMask(Size, -1);
for (int i = 0; i != Size; ++i)
PermuteMask[i] = (i % LaneSize) + (i / LaneSize) * Size;
SDValue NewV1 = DAG.getVectorShuffle(VT, DL, V1, V2, PermuteMask);
for (int i = 0; i != Size; ++i)
PermuteMask[i] = (i % LaneSize) + (i / LaneSize) * Size + LaneSize;
SDValue NewV2 = DAG.getVectorShuffle(VT, DL, V1, V2, PermuteMask);
for (int i = 0; i != Size; ++i) {
int M = RepeatMask[i % LaneSize];
PermuteMask[i] = M;
if (PermuteMask[i] < 0)
RKSimonUnsubmitted
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Do we gain anything by relaxing this and keeping PermuteMask[i] as UNDEF if the original Mask[i] was UNDEF?

RKSimon: Do we gain anything by relaxing this and keeping PermuteMask[i] as UNDEF if the original Mask…
craig.topperAuthorUnsubmitted
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Not sure. I was trying to create a repeated lane shuffle so its based on both lanes. If its undef in both lanes it will be undef here.

craig.topper: Not sure. I was trying to create a repeated lane shuffle so its based on both lanes. If its…
continue;
if (PermuteMask[i] >= LaneSize)
PermuteMask[i] += Size - LaneSize;
PermuteMask[i] += (i / LaneSize) * LaneSize;
}
return DAG.getVectorShuffle(VT, DL, NewV1, NewV2, PermuteMask);
}
/// \brief Handle lowering of 2-lane 64-bit floating point shuffles. /// \brief Handle lowering of 2-lane 64-bit floating point shuffles.
/// ///
/// This is the basis function for the 2-lane 64-bit shuffles as we have full /// This is the basis function for the 2-lane 64-bit shuffles as we have full
/// support for floating point shuffles but not integer shuffles. These /// support for floating point shuffles but not integer shuffles. These
/// instructions will incur a domain crossing penalty on some chips though so /// instructions will incur a domain crossing penalty on some chips though so
/// it is better to avoid lowering through this for integer vectors where /// it is better to avoid lowering through this for integer vectors where
/// possible. /// possible.
static SDValue lowerV2F64VectorShuffle(const SDLoc &DL, ArrayRef<int> Mask, static SDValue lowerV2F64VectorShuffle(const SDLoc &DL, ArrayRef<int> Mask,
▲ Show 20 Lines • Show All 1,924 Lines • ▼ Show 20 Lines
/// This will only succeed when the result of fixing the 128-bit lanes results /// This will only succeed when the result of fixing the 128-bit lanes results
/// in a single-input non-lane-crossing shuffle with a repeating shuffle mask in /// in a single-input non-lane-crossing shuffle with a repeating shuffle mask in
/// each 128-bit lanes. This handles many cases where we can quickly blend away /// each 128-bit lanes. This handles many cases where we can quickly blend away
/// the lane crosses early and then use simpler shuffles within each lane. /// the lane crosses early and then use simpler shuffles within each lane.
/// ///
/// FIXME: It might be worthwhile at some point to support this without /// FIXME: It might be worthwhile at some point to support this without
/// requiring the 128-bit lane-relative shuffles to be repeating, but currently /// requiring the 128-bit lane-relative shuffles to be repeating, but currently
/// in x86 only floating point has interesting non-repeating shuffles, and even /// in x86 only floating point has interesting non-repeating shuffles, and even
/// those are still *marginally* more expensive. /// those are still *marginally* more expensive.
RKSimonUnsubmitted
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This comment + FIXME needs updating

RKSimon: This comment + FIXME needs updating
static SDValue lowerVectorShuffleByMerging128BitLanes( static SDValue lowerVectorShuffleByMerging128BitLanes(
const SDLoc &DL, MVT VT, SDValue V1, SDValue V2, ArrayRef<int> Mask, const SDLoc &DL, MVT VT, SDValue V1, SDValue V2, ArrayRef<int> Mask,
const X86Subtarget &Subtarget, SelectionDAG &DAG) { const X86Subtarget &Subtarget, SelectionDAG &DAG) {
assert(!V2.isUndef() && "This is only useful with multiple inputs."); assert(!V2.isUndef() && "This is only useful with multiple inputs.");
int Size = Mask.size(); int Size = Mask.size();
int LaneSize = 128 / VT.getScalarSizeInBits(); int LaneSize = 128 / VT.getScalarSizeInBits();
int NumLanes = Size / LaneSize; int NumLanes = Size / LaneSize;
RKSimonUnsubmitted
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There is a is128BitLaneRepeatedShuffleMask(VT, Mask) version that you can use instead

RKSimon: There is a is128BitLaneRepeatedShuffleMask(VT, Mask) version that you can use instead
assert(NumLanes > 1 && "Only handles 256-bit and wider shuffles."); assert(NumLanes > 1 && "Only handles 256-bit and wider shuffles.");
// See if we can build a hypothetical 128-bit lane-fixing shuffle mask. Also // See if we can build a hypothetical 128-bit lane-fixing shuffle mask. Also
// check whether the in-128-bit lane shuffles share a repeating pattern. // check whether the in-128-bit lane shuffles share a repeating pattern.
SmallVector<int, 4> Lanes((unsigned)NumLanes, -1); SmallVector<int, 4> Lanes((unsigned)NumLanes, -1);
SmallVector<int, 4> InLaneMask((unsigned)LaneSize, -1); SmallVector<int, 4> InLaneMask((unsigned)LaneSize, -1);
for (int i = 0; i < Size; ++i) { for (int i = 0; i < Size; ++i) {
if (Mask[i] < 0) if (Mask[i] < 0)
RKSimonUnsubmitted
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This seems easier to grok (at least to me):

int Src;
if (Srcs[0] < 0 || Srcs[0] == LaneSrc)
  Src = 0;
else if (Srcs[1] < 0 || Srcs[1] == LaneSrc)
  Src = 1;
else
  return SDValue();

Srcs[Src] = LaneSrc;
InLaneMask[i] = (M % LaneSize) + Src * Size;
RKSimon: This seems easier to grok (at least to me): ``` int Src; if (Srcs[0] < 0 || Srcs[0] == LaneSrc)…
continue; continue;
int j = i / LaneSize; int j = i / LaneSize;
if (Lanes[j] < 0) { if (Lanes[j] < 0) {
// First entry we've seen for this lane. // First entry we've seen for this lane.
Lanes[j] = Mask[i] / LaneSize; Lanes[j] = Mask[i] / LaneSize;
} else if (Lanes[j] != Mask[i] / LaneSize) { } else if (Lanes[j] != Mask[i] / LaneSize) {
// This doesn't match the lane selected previously! // This doesn't match the lane selected previously!
return SDValue(); return SDValue();
} }
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for (int i = 0, e = M1.size(); i != e; ++i)

RKSimon: for (int i = 0, e = M1.size(); i != e; ++i)
// Check that within each lane we have a consistent shuffle mask. // Check that within each lane we have a consistent shuffle mask.
int k = i % LaneSize; int k = i % LaneSize;
if (InLaneMask[k] < 0) { if (InLaneMask[k] < 0) {
InLaneMask[k] = Mask[i] % LaneSize; InLaneMask[k] = Mask[i] % LaneSize;
} else if (InLaneMask[k] != Mask[i] % LaneSize) { } else if (InLaneMask[k] != Mask[i] % LaneSize) {
// This doesn't fit a repeating in-lane mask. // This doesn't fit a repeating in-lane mask.
return SDValue(); return SDValue();
} }
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for (int i = 0, e = MergedMask.size(); i != e; ++i) {

RKSimon: for (int i = 0, e = MergedMask.size(); i != e; ++i) {
} }
// First shuffle the lanes into place. // First shuffle the lanes into place.
MVT LaneVT = MVT::getVectorVT(VT.isFloatingPoint() ? MVT::f64 : MVT::i64, MVT LaneVT = MVT::getVectorVT(VT.isFloatingPoint() ? MVT::f64 : MVT::i64,
VT.getSizeInBits() / 64); VT.getSizeInBits() / 64);
SmallVector<int, 8> LaneMask((unsigned)NumLanes * 2, -1); SmallVector<int, 8> LaneMask((unsigned)NumLanes * 2, -1);
for (int i = 0; i < NumLanes; ++i) for (int i = 0; i < NumLanes; ++i)
if (Lanes[i] >= 0) { if (Lanes[i] >= 0) {
▲ Show 20 Lines • Show All 468 Lines • ▼ Show 20 Lines if (SDValue V = lowerVectorShuffleToEXPAND(DL, MVT::v4f64, Zeroable, Mask,
return V; return V;
// If we have AVX2 then we always want to lower with a blend because an v4 we // If we have AVX2 then we always want to lower with a blend because an v4 we
// can fully permute the elements. // can fully permute the elements.
if (Subtarget.hasAVX2()) if (Subtarget.hasAVX2())
return lowerVectorShuffleAsDecomposedShuffleBlend(DL, MVT::v4f64, V1, V2, return lowerVectorShuffleAsDecomposedShuffleBlend(DL, MVT::v4f64, V1, V2,
Mask, DAG); Mask, DAG);
// Attempt to lower a shuffle where one lane comes from V1 and the other
// lane comes from V2 and the lanes do the same operation. We can create
// a new V1 with the lower lane of V1 and the lower lane of V2. And a new
// V2 with the upper lane of V1 and the upper lane of V2 and then do a
// repeated lane shuffle.
if (SDValue V = lowerVectorShuffleSplitLowHigh(DL, MVT::v4f64, V1, V2,
Mask, DAG))
return V;
// Otherwise fall back on generic lowering. // Otherwise fall back on generic lowering.
return lowerVectorShuffleAsSplitOrBlend(DL, MVT::v4f64, V1, V2, Mask, DAG); return lowerVectorShuffleAsSplitOrBlend(DL, MVT::v4f64, V1, V2, Mask, DAG);
} }
/// \brief Handle lowering of 4-lane 64-bit integer shuffles. /// \brief Handle lowering of 4-lane 64-bit integer shuffles.
/// ///
/// This routine is only called when we have AVX2 and thus a reasonable /// This routine is only called when we have AVX2 and thus a reasonable
/// instruction set for v4i64 shuffling.. /// instruction set for v4i64 shuffling..
▲ Show 20 Lines • Show All 177 Lines • ▼ Show 20 Lines if (SDValue V = lowerVectorShuffleAsSplitOrBlend(DL, MVT::v8f32, V1, V2,
return V; return V;
// If we have AVX2 then we always want to lower with a blend because at v8 we // If we have AVX2 then we always want to lower with a blend because at v8 we
// can fully permute the elements. // can fully permute the elements.
if (Subtarget.hasAVX2()) if (Subtarget.hasAVX2())
return lowerVectorShuffleAsDecomposedShuffleBlend(DL, MVT::v8f32, V1, V2, return lowerVectorShuffleAsDecomposedShuffleBlend(DL, MVT::v8f32, V1, V2,
Mask, DAG); Mask, DAG);
// Attempt to lower a shuffle where one lane comes from V1 and the other
// lane comes from V2 and the lanes do the same operation. We can create
// a new V1 with the lower lane of V1 and the lower lane of V2. And a new
// V2 with the upper lane of V1 and the upper lane of V2 and then do a
// repeated lane shuffle.
if (SDValue V = lowerVectorShuffleSplitLowHigh(DL, MVT::v8f32, V1, V2,
Mask, DAG))
return V;
// Otherwise fall back on generic lowering. // Otherwise fall back on generic lowering.
return lowerVectorShuffleAsSplitOrBlend(DL, MVT::v8f32, V1, V2, Mask, DAG); return lowerVectorShuffleAsSplitOrBlend(DL, MVT::v8f32, V1, V2, Mask, DAG);
} }
/// \brief Handle lowering of 8-lane 32-bit integer shuffles. /// \brief Handle lowering of 8-lane 32-bit integer shuffles.
/// ///
/// This routine is only called when we have AVX2 and thus a reasonable /// This routine is only called when we have AVX2 and thus a reasonable
/// instruction set for v8i32 shuffling.. /// instruction set for v8i32 shuffling..
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