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[x86] Factor out the logic to generically decombose a vector shuffle 

into unblended shuffles and a blend.

This is the consistent fallback for the lowering paths that have fast
blend operations available, and its getting quite repetitive.

No functionality changed.

llvm-svn: 218399
This commit is contained in:
Chandler Carruth 2014-09-24 18:20:09 +00:00
parent c4067328cf
commit edcba62b4a
1 changed files with 42 additions and 72 deletions
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114
llvm/lib/Target/X86/X86ISelLowering.cpp
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@ -7317,6 +7317,36 @@ static SDValue lowerVectorShuffleAsBlend(SDLoc DL, MVT VT, SDValue V1,
}
}
/// \brief Generic routine to lower a shuffle and blend as a decomposed set of
/// unblended shuffles followed by an unshuffled blend.
///
/// This matches the extremely common pattern for handling combined
/// shuffle+blend operations on newer X86 ISAs where we have very fast blend
/// operations.
static SDValue lowerVectorShuffleAsDecomposedShuffleBlend(SDLoc DL, MVT VT,
SDValue V1,
SDValue V2,
ArrayRef<int> Mask,
SelectionDAG &DAG) {
// Shuffle the input elements into the desired positions in V1 and V2 and
// blend them together.
SmallVector<int, 32> V1Mask(Mask.size(), -1);
SmallVector<int, 32> V2Mask(Mask.size(), -1);
SmallVector<int, 32> BlendMask(Mask.size(), -1);
for (int i = 0, Size = Mask.size(); i < Size; ++i)
if (Mask[i] >= 0 && Mask[i] < Size) {
V1Mask[i] = Mask[i];
BlendMask[i] = i;
} else if (Mask[i] >= Size) {
V2Mask[i] = Mask[i] - Size;
BlendMask[i] = i + Size;
}
V1 = DAG.getVectorShuffle(VT, DL, V1, DAG.getUNDEF(VT), V1Mask);
V2 = DAG.getVectorShuffle(VT, DL, V2, DAG.getUNDEF(VT), V2Mask);
return DAG.getVectorShuffle(VT, DL, V1, V2, BlendMask);
}
/// \brief Try to lower a vector shuffle as a byte rotation.
///
/// We have a generic PALIGNR instruction in x86 that will do an arbitrary
@ -9362,26 +9392,9 @@ static SDValue lowerV4F64VectorShuffle(SDValue Op, SDValue V1, SDValue V2,
DAG.getConstant(SHUFPDMask, MVT::i8));
}
// Shuffle the input elements into the desired positions in V1 and V2 and
// blend them together.
int V1Mask[] = {-1, -1, -1, -1};
int V2Mask[] = {-1, -1, -1, -1};
for (int i = 0; i < 4; ++i)
if (Mask[i] >= 0 && Mask[i] < 4)
V1Mask[i] = Mask[i];
else if (Mask[i] >= 4)
V2Mask[i] = Mask[i] - 4;
V1 = DAG.getVectorShuffle(MVT::v4f64, DL, V1, DAG.getUNDEF(MVT::v4f64), V1Mask);
V2 = DAG.getVectorShuffle(MVT::v4f64, DL, V2, DAG.getUNDEF(MVT::v4f64), V2Mask);
unsigned BlendMask = 0;
for (int i = 0; i < 4; ++i)
if (Mask[i] >= 4)
BlendMask |= 1 << i;
return DAG.getNode(X86ISD::BLENDI, DL, MVT::v4f64, V1, V2,
DAG.getConstant(BlendMask, MVT::i8));
// Otherwise fall back on generic blend lowering.
return lowerVectorShuffleAsDecomposedShuffleBlend(DL, MVT::v4f64, V1, V2,
Mask, DAG);
}
/// \brief Handle lowering of 4-lane 64-bit integer shuffles.
@ -9434,23 +9447,9 @@ static SDValue lowerV4I64VectorShuffle(SDValue Op, SDValue V1, SDValue V2,
return DAG.getNode(X86ISD::VPERMI, DL, MVT::v4i64, V1,
getV4X86ShuffleImm8ForMask(Mask, DAG));
// Shuffle the input elements into the desired positions in V1 and V2 and
// blend them together.
int V1Mask[] = {-1, -1, -1, -1};
int V2Mask[] = {-1, -1, -1, -1};
int BlendMask[] = {-1, -1, -1, -1};
for (int i = 0; i < 4; ++i)
if (Mask[i] >= 0 && Mask[i] < 4) {
V1Mask[i] = Mask[i];
BlendMask[i] = i;
} else if (Mask[i] >= 4) {
V2Mask[i] = Mask[i] - 4;
BlendMask[i] = i + 4;
}
V1 = DAG.getVectorShuffle(MVT::v4i64, DL, V1, DAG.getUNDEF(MVT::v4i64), V1Mask);
V2 = DAG.getVectorShuffle(MVT::v4i64, DL, V2, DAG.getUNDEF(MVT::v4i64), V2Mask);
return DAG.getVectorShuffle(MVT::v4i64, DL, V1, V2, BlendMask);
// Otherwise fall back on generic blend lowering.
return lowerVectorShuffleAsDecomposedShuffleBlend(DL, MVT::v4i64, V1, V2,
Mask, DAG);
}
/// \brief Handle lowering of 8-lane 32-bit floating point shuffles.
@ -9509,24 +9508,9 @@ static SDValue lowerV8F32VectorShuffle(SDValue Op, SDValue V1, SDValue V2,
DAG.getNode(ISD::BUILD_VECTOR, DL, MVT::v8i32, VPermMask));
}
// Shuffle the input elements into the desired positions in V1 and V2 and
// blend them together.
int V1Mask[] = {-1, -1, -1, -1, -1, -1, -1, -1};
int V2Mask[] = {-1, -1, -1, -1, -1, -1, -1, -1};
unsigned BlendMask = 0;
for (int i = 0; i < 8; ++i)
if (Mask[i] >= 0 && Mask[i] < 8) {
V1Mask[i] = Mask[i];
} else if (Mask[i] >= 8) {
V2Mask[i] = Mask[i] - 8;
BlendMask |= 1 << i;
}
V1 = DAG.getVectorShuffle(MVT::v8f32, DL, V1, DAG.getUNDEF(MVT::v8f32), V1Mask);
V2 = DAG.getVectorShuffle(MVT::v8f32, DL, V2, DAG.getUNDEF(MVT::v8f32), V2Mask);
return DAG.getNode(X86ISD::BLENDI, DL, MVT::v8f32, V1, V2,
DAG.getConstant(BlendMask, MVT::i8));
// Otherwise fall back on generic blend lowering.
return lowerVectorShuffleAsDecomposedShuffleBlend(DL, MVT::v8f32, V1, V2,
Mask, DAG);
}
/// \brief Handle lowering of 8-lane 32-bit integer shuffles.
@ -9577,23 +9561,9 @@ static SDValue lowerV8I32VectorShuffle(SDValue Op, SDValue V1, SDValue V2,
DAG.getNode(ISD::BUILD_VECTOR, DL, MVT::v8i32, VPermMask), V1);
}
// Shuffle the input elements into the desired positions in V1 and V2 and
// blend them together.
int V1Mask[] = {-1, -1, -1, -1, -1, -1, -1, -1};
int V2Mask[] = {-1, -1, -1, -1, -1, -1, -1, -1};
int BlendMask[] = {-1, -1, -1, -1, -1, -1, -1, -1};
for (int i = 0; i < 8; ++i)
if (Mask[i] >= 0 && Mask[i] < 8) {
V1Mask[i] = Mask[i];
BlendMask[i] = i;
} else if (Mask[i] >= 8) {
V2Mask[i] = Mask[i] - 8;
BlendMask[i] = i + 8;
}
V1 = DAG.getVectorShuffle(MVT::v8i32, DL, V1, DAG.getUNDEF(MVT::v8i32), V1Mask);
V2 = DAG.getVectorShuffle(MVT::v8i32, DL, V2, DAG.getUNDEF(MVT::v8i32), V2Mask);
return DAG.getVectorShuffle(MVT::v8i32, DL, V1, V2, BlendMask);
// Otherwise fall back on generic blend lowering.
return lowerVectorShuffleAsDecomposedShuffleBlend(DL, MVT::v8i32, V1, V2,
Mask, DAG);
}
/// \brief Handle lowering of 16-lane 16-bit integer shuffles.