Use a target-specific VMOVIMM DAG node instead of BUILD_VECTOR to represent
NEON VMOV-immediate instructions. This simplifies some things.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@108275 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Target/ARM/ARMISelLowering.cpp b/lib/Target/ARM/ARMISelLowering.cpp
index d56b157..762e9b0 100644
--- a/lib/Target/ARM/ARMISelLowering.cpp
+++ b/lib/Target/ARM/ARMISelLowering.cpp
@@ -624,6 +624,7 @@
case ARMISD::VQRSHRNsu: return "ARMISD::VQRSHRNsu";
case ARMISD::VGETLANEu: return "ARMISD::VGETLANEu";
case ARMISD::VGETLANEs: return "ARMISD::VGETLANEs";
+ case ARMISD::VMOVIMM: return "ARMISD::VMOVIMM";
case ARMISD::VDUP: return "ARMISD::VDUP";
case ARMISD::VDUPLANE: return "ARMISD::VDUPLANE";
case ARMISD::VEXT: return "ARMISD::VEXT";
@@ -2644,51 +2645,18 @@
}
/// getZeroVector - Returns a vector of specified type with all zero elements.
-///
+/// Zero vectors are used to represent vector negation and in those cases
+/// will be implemented with the NEON VNEG instruction. However, VNEG does
+/// not support i64 elements, so sometimes the zero vectors will need to be
+/// explicitly constructed. Regardless, use a canonical VMOV to create the
+/// zero vector.
static SDValue getZeroVector(EVT VT, SelectionDAG &DAG, DebugLoc dl) {
assert(VT.isVector() && "Expected a vector type");
-
- // Zero vectors are used to represent vector negation and in those cases
- // will be implemented with the NEON VNEG instruction. However, VNEG does
- // not support i64 elements, so sometimes the zero vectors will need to be
- // explicitly constructed. For those cases, and potentially other uses in
- // the future, always build zero vectors as <16 x i8> or <8 x i8> bitcasted
- // to their dest type. This ensures they get CSE'd.
- SDValue Vec;
- SDValue Cst = DAG.getTargetConstant(0, MVT::i8);
- SmallVector<SDValue, 8> Ops;
- MVT TVT;
-
- if (VT.getSizeInBits() == 64) {
- Ops.assign(8, Cst); TVT = MVT::v8i8;
- } else {
- Ops.assign(16, Cst); TVT = MVT::v16i8;
- }
- Vec = DAG.getNode(ISD::BUILD_VECTOR, dl, TVT, &Ops[0], Ops.size());
-
- return DAG.getNode(ISD::BIT_CONVERT, dl, VT, Vec);
-}
-
-/// getOnesVector - Returns a vector of specified type with all bits set.
-///
-static SDValue getOnesVector(EVT VT, SelectionDAG &DAG, DebugLoc dl) {
- assert(VT.isVector() && "Expected a vector type");
-
- // Always build ones vectors as <16 x i8> or <8 x i8> bitcasted to their
- // dest type. This ensures they get CSE'd.
- SDValue Vec;
- SDValue Cst = DAG.getTargetConstant(0xFF, MVT::i8);
- SmallVector<SDValue, 8> Ops;
- MVT TVT;
-
- if (VT.getSizeInBits() == 64) {
- Ops.assign(8, Cst); TVT = MVT::v8i8;
- } else {
- Ops.assign(16, Cst); TVT = MVT::v16i8;
- }
- Vec = DAG.getNode(ISD::BUILD_VECTOR, dl, TVT, &Ops[0], Ops.size());
-
- return DAG.getNode(ISD::BIT_CONVERT, dl, VT, Vec);
+ // The canonical modified immediate encoding of a zero vector is....0!
+ SDValue EncodedVal = DAG.getTargetConstant(0, MVT::i32);
+ EVT VmovVT = VT.is128BitVector() ? MVT::v4i32 : MVT::v2i32;
+ SDValue Vmov = DAG.getNode(ARMISD::VMOVIMM, dl, VmovVT, EncodedVal);
+ return DAG.getNode(ISD::BIT_CONVERT, dl, VT, Vmov);
}
/// LowerShiftRightParts - Lower SRA_PARTS, which returns two
@@ -2941,13 +2909,11 @@
/// isNEONModifiedImm - Check if the specified splat value corresponds to a
/// valid vector constant for a NEON instruction with a "modified immediate"
-/// operand (e.g., VMOV). If so, return either the constant being
-/// splatted or the encoded value, depending on the DoEncode parameter.
+/// operand (e.g., VMOV). If so, return the encoded value.
static SDValue isNEONModifiedImm(uint64_t SplatBits, uint64_t SplatUndef,
unsigned SplatBitSize, SelectionDAG &DAG,
- bool isVMOV, bool DoEncode) {
+ EVT &VT, bool is128Bits, bool isVMOV) {
unsigned OpCmode, Imm;
- EVT VT;
// SplatBitSize is set to the smallest size that splats the vector, so a
// zero vector will always have SplatBitSize == 8. However, NEON modified
@@ -2963,12 +2929,12 @@
assert((SplatBits & ~0xff) == 0 && "one byte splat value is too big");
OpCmode = 0xe;
Imm = SplatBits;
- VT = MVT::i8;
+ VT = is128Bits ? MVT::v16i8 : MVT::v8i8;
break;
case 16:
// NEON's 16-bit VMOV supports splat values where only one byte is nonzero.
- VT = MVT::i16;
+ VT = is128Bits ? MVT::v8i16 : MVT::v4i16;
if ((SplatBits & ~0xff) == 0) {
// Value = 0x00nn: Op=x, Cmode=100x.
OpCmode = 0x8;
@@ -2988,7 +2954,7 @@
// * only one byte is nonzero, or
// * the least significant byte is 0xff and the second byte is nonzero, or
// * the least significant 2 bytes are 0xff and the third is nonzero.
- VT = MVT::i32;
+ VT = is128Bits ? MVT::v4i32 : MVT::v2i32;
if ((SplatBits & ~0xff) == 0) {
// Value = 0x000000nn: Op=x, Cmode=000x.
OpCmode = 0;
@@ -3060,7 +3026,7 @@
// Op=1, Cmode=1110.
OpCmode = 0x1e;
SplatBits = Val;
- VT = MVT::i64;
+ VT = is128Bits ? MVT::v2i64 : MVT::v1i64;
break;
}
@@ -3069,32 +3035,8 @@
return SDValue();
}
- if (DoEncode) {
- unsigned EncodedVal = ARM_AM::createNEONModImm(OpCmode, Imm);
- return DAG.getTargetConstant(EncodedVal, MVT::i32);
- }
- return DAG.getTargetConstant(SplatBits, VT);
-}
-
-/// getNEONModImm - If this is a valid vector constant for a NEON instruction
-/// with a "modified immediate" operand (e.g., VMOV) of the specified element
-/// size, return the encoded value for that immediate. The ByteSize field
-/// indicates the number of bytes of each element [1248].
-SDValue ARM::getNEONModImm(SDNode *N, unsigned ByteSize, bool isVMOV,
- SelectionDAG &DAG) {
- BuildVectorSDNode *BVN = dyn_cast<BuildVectorSDNode>(N);
- APInt SplatBits, SplatUndef;
- unsigned SplatBitSize;
- bool HasAnyUndefs;
- if (! BVN || ! BVN->isConstantSplat(SplatBits, SplatUndef, SplatBitSize,
- HasAnyUndefs, ByteSize * 8))
- return SDValue();
-
- if (SplatBitSize > ByteSize * 8)
- return SDValue();
-
- return isNEONModifiedImm(SplatBits.getZExtValue(), SplatUndef.getZExtValue(),
- SplatBitSize, DAG, isVMOV, true);
+ unsigned EncodedVal = ARM_AM::createNEONModImm(OpCmode, Imm);
+ return DAG.getTargetConstant(EncodedVal, MVT::i32);
}
static bool isVEXTMask(const SmallVectorImpl<int> &M, EVT VT,
@@ -3285,43 +3227,6 @@
return true;
}
-
-static SDValue BuildSplat(SDValue Val, EVT VT, SelectionDAG &DAG, DebugLoc dl) {
- // Canonicalize all-zeros and all-ones vectors.
- ConstantSDNode *ConstVal = cast<ConstantSDNode>(Val.getNode());
- if (ConstVal->isNullValue())
- return getZeroVector(VT, DAG, dl);
- if (ConstVal->isAllOnesValue())
- return getOnesVector(VT, DAG, dl);
-
- EVT CanonicalVT;
- if (VT.is64BitVector()) {
- switch (Val.getValueType().getSizeInBits()) {
- case 8: CanonicalVT = MVT::v8i8; break;
- case 16: CanonicalVT = MVT::v4i16; break;
- case 32: CanonicalVT = MVT::v2i32; break;
- case 64: CanonicalVT = MVT::v1i64; break;
- default: llvm_unreachable("unexpected splat element type"); break;
- }
- } else {
- assert(VT.is128BitVector() && "unknown splat vector size");
- switch (Val.getValueType().getSizeInBits()) {
- case 8: CanonicalVT = MVT::v16i8; break;
- case 16: CanonicalVT = MVT::v8i16; break;
- case 32: CanonicalVT = MVT::v4i32; break;
- case 64: CanonicalVT = MVT::v2i64; break;
- default: llvm_unreachable("unexpected splat element type"); break;
- }
- }
-
- // Build a canonical splat for this value.
- SmallVector<SDValue, 8> Ops;
- Ops.assign(CanonicalVT.getVectorNumElements(), Val);
- SDValue Res = DAG.getNode(ISD::BUILD_VECTOR, dl, CanonicalVT, &Ops[0],
- Ops.size());
- return DAG.getNode(ISD::BIT_CONVERT, dl, VT, Res);
-}
-
// If this is a case we can't handle, return null and let the default
// expansion code take care of it.
static SDValue LowerBUILD_VECTOR(SDValue Op, SelectionDAG &DAG) {
@@ -3335,11 +3240,14 @@
if (BVN->isConstantSplat(SplatBits, SplatUndef, SplatBitSize, HasAnyUndefs)) {
if (SplatBitSize <= 64) {
// Check if an immediate VMOV works.
+ EVT VmovVT;
SDValue Val = isNEONModifiedImm(SplatBits.getZExtValue(),
- SplatUndef.getZExtValue(),
- SplatBitSize, DAG, true, false);
- if (Val.getNode())
- return BuildSplat(Val, VT, DAG, dl);
+ SplatUndef.getZExtValue(), SplatBitSize,
+ DAG, VmovVT, VT.is128BitVector(), true);
+ if (Val.getNode()) {
+ SDValue Vmov = DAG.getNode(ARMISD::VMOVIMM, dl, VmovVT, Val);
+ return DAG.getNode(ISD::BIT_CONVERT, dl, VT, Vmov);
+ }
}
}