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[X86] Remove 128-bit lane handling from the main loop of matchVectorShuffleAsByteRotate. Instead check for is128LaneRepeatedSuffleMask before the loop and just loop over the repeated mask. 

I plan to use the loop to support VALIGND/Q shuffles so this makes it easier to reuse.

llvm-svn: 284912
This commit is contained in:
Craig Topper 2016-10-22 06:51:44 +00:00
parent 0d376bcbf0
commit bea5cb5491
1 changed files with 47 additions and 52 deletions
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99
llvm/lib/Target/X86/X86ISelLowering.cpp
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@ -7126,6 +7126,7 @@ static bool isRepeatedShuffleMask(unsigned LaneSizeInBits, MVT VT,
RepeatedMask.assign(LaneSize, -1);
int Size = Mask.size();
for (int i = 0; i < Size; ++i) {
assert(Mask[i] == SM_SentinelUndef || Mask[i] >= 0);
if (Mask[i] < 0)
continue;
if ((Mask[i] % Size) / LaneSize != i / LaneSize)
@ -7760,9 +7761,16 @@ static SDValue lowerVectorShuffleAsDecomposedShuffleBlend(const SDLoc &DL,
/// rotate* of the vector lanes.
static int matchVectorShuffleAsByteRotate(MVT VT, SDValue &V1, SDValue &V2,
ArrayRef<int> Mask) {
int NumElts = Mask.size();
int NumLanes = VT.getSizeInBits() / 128;
int NumLaneElts = NumElts / NumLanes;
// Don't accept any shuffles with zero elements.
if (any_of(Mask, [](int M) { return M == SM_SentinelZero; }))
return -1;
// PALIGNR works on 128-bit lanes.
SmallVector<int, 16> RepeatedMask;
if (!is128BitLaneRepeatedShuffleMask(VT, Mask, RepeatedMask))
return -1;
int NumElts = RepeatedMask.size();
// We need to detect various ways of spelling a rotation:
// [11, 12, 13, 14, 15, 0, 1, 2]
@ -7773,59 +7781,46 @@ static int matchVectorShuffleAsByteRotate(MVT VT, SDValue &V1, SDValue &V2,
// [-1, 4, 5, 6, -1, -1, -1, -1]
int Rotation = 0;
SDValue Lo, Hi;
for (int l = 0; l < NumElts; l += NumLaneElts) {
for (int i = 0; i < NumLaneElts; ++i) {
int M = Mask[l + i];
for (int i = 0; i < NumElts; ++i) {
int M = RepeatedMask[i];
assert((M == SM_SentinelUndef || (0 <= M && M < (2*NumElts))) &&
"Unexpected mask index.");
if (M < 0)
continue;
if (M == SM_SentinelUndef)
continue;
// Determine where a rotated vector would have started.
int StartIdx = i - (M % NumElts);
if (StartIdx == 0)
// The identity rotation isn't interesting, stop.
return -1;
if (M == SM_SentinelZero)
return -1;
// If we found the tail of a vector the rotation must be the missing
// front. If we found the head of a vector, it must be how much of the
// head.
int CandidateRotation = StartIdx < 0 ? -StartIdx : NumElts - StartIdx;
assert(0 <= M && M < (2*NumElts) && "Unexpected mask index.");
if (Rotation == 0)
Rotation = CandidateRotation;
else if (Rotation != CandidateRotation)
// The rotations don't match, so we can't match this mask.
return -1;
// Get the mod-Size index and lane correct it.
int LaneIdx = (M % NumElts) - l;
// Compute which value this mask is pointing at.
SDValue MaskV = M < NumElts ? V1 : V2;
// Make sure it was in this lane.
if (LaneIdx < 0 || LaneIdx >= NumLaneElts)
return -1;
// Compute which of the two target values this index should be assigned
// to. This reflects whether the high elements are remaining or the low
// elements are remaining.
SDValue &TargetV = StartIdx < 0 ? Hi : Lo;
// Determine where a rotated vector would have started.
int StartIdx = i - LaneIdx;
if (StartIdx == 0)
// The identity rotation isn't interesting, stop.
return -1;
// If we found the tail of a vector the rotation must be the missing
// front. If we found the head of a vector, it must be how much of the
// head.
int CandidateRotation = StartIdx < 0 ? -StartIdx : NumLaneElts - StartIdx;
if (Rotation == 0)
Rotation = CandidateRotation;
else if (Rotation != CandidateRotation)
// The rotations don't match, so we can't match this mask.
return -1;
// Compute which value this mask is pointing at.
SDValue MaskV = M < NumElts ? V1 : V2;
// Compute which of the two target values this index should be assigned
// to. This reflects whether the high elements are remaining or the low
// elements are remaining.
SDValue &TargetV = StartIdx < 0 ? Hi : Lo;
// Either set up this value if we've not encountered it before, or check
// that it remains consistent.
if (!TargetV)
TargetV = MaskV;
else if (TargetV != MaskV)
// This may be a rotation, but it pulls from the inputs in some
// unsupported interleaving.
return -1;
}
// Either set up this value if we've not encountered it before, or check
// that it remains consistent.
if (!TargetV)
TargetV = MaskV;
else if (TargetV != MaskV)
// This may be a rotation, but it pulls from the inputs in some
// unsupported interleaving.
return -1;
}
// Check that we successfully analyzed the mask, and normalize the results.
@ -7839,9 +7834,9 @@ static int matchVectorShuffleAsByteRotate(MVT VT, SDValue &V1, SDValue &V2,
V1 = Lo;
V2 = Hi;
// The actual rotate instruction rotates bytes, so we need to scale the
// PALIGNR rotates bytes, so we need to scale the
// rotation based on how many bytes are in the vector lane.
int Scale = 16 / NumLaneElts;
int Scale = 16 / NumElts;
return Rotation * Scale;
}