diff options
Diffstat (limited to 'llvm/lib')
| -rw-r--r-- | llvm/lib/Target/X86/X86ISelLowering.cpp | 22 |
1 files changed, 14 insertions, 8 deletions
diff --git a/llvm/lib/Target/X86/X86ISelLowering.cpp b/llvm/lib/Target/X86/X86ISelLowering.cpp index e2e63eb4c18..032c2106543 100644 --- a/llvm/lib/Target/X86/X86ISelLowering.cpp +++ b/llvm/lib/Target/X86/X86ISelLowering.cpp @@ -11964,10 +11964,9 @@ static SDValue lowerVectorShuffleAsInsertPS(const SDLoc &DL, SDValue V1, /// because for floating point vectors we have a generalized SHUFPS lowering /// strategy that handles everything that doesn't *exactly* match an unpack, /// making this clever lowering unnecessary. -static SDValue lowerVectorShuffleAsPermuteAndUnpack(const SDLoc &DL, MVT VT, - SDValue V1, SDValue V2, - ArrayRef<int> Mask, - SelectionDAG &DAG) { +static SDValue lowerVectorShuffleAsPermuteAndUnpack( + const SDLoc &DL, MVT VT, SDValue V1, SDValue V2, ArrayRef<int> Mask, + const X86Subtarget &Subtarget, SelectionDAG &DAG) { assert(!VT.isFloatingPoint() && "This routine only supports integer vectors."); assert(VT.is128BitVector() && @@ -12036,6 +12035,13 @@ static SDValue lowerVectorShuffleAsPermuteAndUnpack(const SDLoc &DL, MVT VT, if (SDValue Unpack = TryUnpack(ScalarSize, ScalarSize / OrigScalarSize)) return Unpack; + // If we have PSHUFB, and we're shuffling with a zero vector then we're + // better off not doing VECTOR_SHUFFLE(UNPCK()) as we lose track of those + // zero elements. + if (Subtarget.hasSSSE3() && (ISD::isBuildVectorAllZeros(V1.getNode()) || + ISD::isBuildVectorAllZeros(V2.getNode()))) + return SDValue(); + // If none of the unpack-rooted lowerings worked (or were profitable) try an // initial unpack. if (NumLoInputs == 0 || NumHiInputs == 0) { @@ -12549,7 +12555,7 @@ static SDValue lowerV4I32VectorShuffle(const SDLoc &DL, ArrayRef<int> Mask, // Try to lower by permuting the inputs into an unpack instruction. if (SDValue Unpack = lowerVectorShuffleAsPermuteAndUnpack( - DL, MVT::v4i32, V1, V2, Mask, DAG)) + DL, MVT::v4i32, V1, V2, Mask, Subtarget, DAG)) return Unpack; } @@ -13245,8 +13251,8 @@ static SDValue lowerV8I16VectorShuffle(const SDLoc &DL, ArrayRef<int> Mask, return BitBlend; // Try to lower by permuting the inputs into an unpack instruction. - if (SDValue Unpack = lowerVectorShuffleAsPermuteAndUnpack(DL, MVT::v8i16, V1, - V2, Mask, DAG)) + if (SDValue Unpack = lowerVectorShuffleAsPermuteAndUnpack( + DL, MVT::v8i16, V1, V2, Mask, Subtarget, DAG)) return Unpack; // If we can't directly blend but can use PSHUFB, that will be better as it @@ -13534,7 +13540,7 @@ static SDValue lowerV16I8VectorShuffle(const SDLoc &DL, ArrayRef<int> Mask, // shuffles will both be pshufb, in which case we shouldn't bother with // this. if (SDValue Unpack = lowerVectorShuffleAsPermuteAndUnpack( - DL, MVT::v16i8, V1, V2, Mask, DAG)) + DL, MVT::v16i8, V1, V2, Mask, Subtarget, DAG)) return Unpack; // If we have VBMI we can use one VPERM instead of multiple PSHUFBs. |
