[llvm] r174325 - SelectionDAG: Teach FoldConstantArithmetic how to deal with vectors.
Hal Finkel
hfinkel at anl.gov
Mon Feb 4 07:43:14 PST 2013
----- Original Message -----
> From: "Benjamin Kramer" <benny.kra at googlemail.com>
> To: llvm-commits at cs.uiuc.edu
> Sent: Monday, February 4, 2013 9:19:18 AM
> Subject: [llvm] r174325 - SelectionDAG: Teach FoldConstantArithmetic how to deal with vectors.
>
> Author: d0k
> Date: Mon Feb 4 09:19:18 2013
> New Revision: 174325
>
> URL: http://llvm.org/viewvc/llvm-project?rev=174325&view=rev
> Log:
> SelectionDAG: Teach FoldConstantArithmetic how to deal with vectors.
>
> This required disabling a PowerPC optimization that did the
> following:
> input:
> x = BUILD_VECTOR <i32 16, i32 16, i32 16, i32 16>
> lowered to:
> tmp = BUILD_VECTOR <i32 8, i32 8, i32 8, i32 8>
> x = ADD tmp, tmp
>
> The add now gets folded immediately and we're back at the
> BUILD_VECTOR we
> started from. I don't see a way to fix this currently so I left it
> disabled
> for now.
Can we add a TLI callback to disable this so that PPC can avoid this optimization?
Thanks again,
Hal
>
> Fix some trivially foldable X86 tests too.
>
> Modified:
> llvm/trunk/include/llvm/CodeGen/SelectionDAG.h
> llvm/trunk/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
> llvm/trunk/lib/Target/PowerPC/PPCISelLowering.cpp
> llvm/trunk/test/CodeGen/PowerPC/2008-07-10-SplatMiscompile.ll
> llvm/trunk/test/CodeGen/X86/2011-11-30-or.ll
> llvm/trunk/test/CodeGen/X86/blend-msb.ll
> llvm/trunk/test/CodeGen/X86/vector-gep.ll
>
> Modified: llvm/trunk/include/llvm/CodeGen/SelectionDAG.h
> URL:
> http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm/CodeGen/SelectionDAG.h?rev=174325&r1=174324&r2=174325&view=diff
> ==============================================================================
> --- llvm/trunk/include/llvm/CodeGen/SelectionDAG.h (original)
> +++ llvm/trunk/include/llvm/CodeGen/SelectionDAG.h Mon Feb 4
> 09:19:18 2013
> @@ -992,10 +992,8 @@ public:
> SDValue CreateStackTemporary(EVT VT1, EVT VT2);
>
> /// FoldConstantArithmetic -
> - SDValue FoldConstantArithmetic(unsigned Opcode,
> - EVT VT,
> - ConstantSDNode *Cst1,
> - ConstantSDNode *Cst2);
> + SDValue FoldConstantArithmetic(unsigned Opcode, EVT VT,
> + SDNode *Cst1, SDNode *Cst2);
>
> /// FoldSetCC - Constant fold a setcc to true or false.
> SDValue FoldSetCC(EVT VT, SDValue N1,
>
> Modified: llvm/trunk/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
> URL:
> http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/SelectionDAG/SelectionDAG.cpp?rev=174325&r1=174324&r2=174325&view=diff
> ==============================================================================
> --- llvm/trunk/lib/CodeGen/SelectionDAG/SelectionDAG.cpp (original)
> +++ llvm/trunk/lib/CodeGen/SelectionDAG/SelectionDAG.cpp Mon Feb 4
> 09:19:18 2013
> @@ -2680,44 +2680,117 @@ SDValue SelectionDAG::getNode(unsigned O
> return SDValue(N, 0);
> }
>
> -SDValue SelectionDAG::FoldConstantArithmetic(unsigned Opcode,
> - EVT VT,
> - ConstantSDNode *Cst1,
> - ConstantSDNode *Cst2) {
> - const APInt &C1 = Cst1->getAPIntValue(), &C2 =
> Cst2->getAPIntValue();
> +SDValue SelectionDAG::FoldConstantArithmetic(unsigned Opcode, EVT
> VT,
> + SDNode *Cst1, SDNode
> *Cst2) {
> + SmallVector<std::pair<ConstantSDNode *, ConstantSDNode *>, 4>
> Inputs;
> + SmallVector<SDValue, 4> Outputs;
> + EVT SVT = VT.getScalarType();
> +
> + ConstantSDNode *Scalar1 = dyn_cast<ConstantSDNode>(Cst1);
> + ConstantSDNode *Scalar2 = dyn_cast<ConstantSDNode>(Cst2);
> + if (Scalar1 && Scalar2) {
> + // Scalar instruction.
> + Inputs.push_back(std::make_pair(Scalar1, Scalar2));
> + } else {
> + // For vectors extract each constant element into Inputs so we
> can constant
> + // fold them individually.
> + BuildVectorSDNode *BV1 = dyn_cast<BuildVectorSDNode>(Cst1);
> + BuildVectorSDNode *BV2 = dyn_cast<BuildVectorSDNode>(Cst2);
> + if (!BV1 || !BV2)
> + return SDValue();
> +
> + assert(BV1->getNumOperands() == BV2->getNumOperands() && "Out of
> sync!");
> +
> + for (unsigned I = 0, E = BV1->getNumOperands(); I != E; ++I) {
> + ConstantSDNode *V1 =
> dyn_cast<ConstantSDNode>(BV1->getOperand(I));
> + ConstantSDNode *V2 =
> dyn_cast<ConstantSDNode>(BV2->getOperand(I));
> + if (!V1 || !V2) // Not a constant, bail.
> + return SDValue();
> +
> + // Avoid BUILD_VECTOR nodes that perform implicit truncation.
> + // FIXME: This is valid and could be handled by truncating the
> APInts.
> + if (V1->getValueType(0) != SVT || V2->getValueType(0) != SVT)
> + return SDValue();
> +
> + Inputs.push_back(std::make_pair(V1, V2));
> + }
> + }
>
> - switch (Opcode) {
> - case ISD::ADD: return getConstant(C1 + C2, VT);
> - case ISD::SUB: return getConstant(C1 - C2, VT);
> - case ISD::MUL: return getConstant(C1 * C2, VT);
> - case ISD::UDIV:
> - if (C2.getBoolValue()) return getConstant(C1.udiv(C2), VT);
> - break;
> - case ISD::UREM:
> - if (C2.getBoolValue()) return getConstant(C1.urem(C2), VT);
> - break;
> - case ISD::SDIV:
> - if (C2.getBoolValue()) return getConstant(C1.sdiv(C2), VT);
> - break;
> - case ISD::SREM:
> - if (C2.getBoolValue()) return getConstant(C1.srem(C2), VT);
> - break;
> - case ISD::AND: return getConstant(C1 & C2, VT);
> - case ISD::OR: return getConstant(C1 | C2, VT);
> - case ISD::XOR: return getConstant(C1 ^ C2, VT);
> - case ISD::SHL: return getConstant(C1 << C2, VT);
> - case ISD::SRL: return getConstant(C1.lshr(C2), VT);
> - case ISD::SRA: return getConstant(C1.ashr(C2), VT);
> - case ISD::ROTL: return getConstant(C1.rotl(C2), VT);
> - case ISD::ROTR: return getConstant(C1.rotr(C2), VT);
> - default: break;
> + // We have a number of constant values, constant fold them element
> by element.
> + for (unsigned I = 0, E = Inputs.size(); I != E; ++I) {
> + const APInt &C1 = Inputs[I].first->getAPIntValue();
> + const APInt &C2 = Inputs[I].second->getAPIntValue();
> +
> + switch (Opcode) {
> + case ISD::ADD:
> + Outputs.push_back(getConstant(C1 + C2, SVT));
> + break;
> + case ISD::SUB:
> + Outputs.push_back(getConstant(C1 - C2, SVT));
> + break;
> + case ISD::MUL:
> + Outputs.push_back(getConstant(C1 * C2, SVT));
> + break;
> + case ISD::UDIV:
> + if (!C2.getBoolValue())
> + return SDValue();
> + Outputs.push_back(getConstant(C1.udiv(C2), SVT));
> + break;
> + case ISD::UREM:
> + if (!C2.getBoolValue())
> + return SDValue();
> + Outputs.push_back(getConstant(C1.urem(C2), SVT));
> + break;
> + case ISD::SDIV:
> + if (!C2.getBoolValue())
> + return SDValue();
> + Outputs.push_back(getConstant(C1.sdiv(C2), SVT));
> + break;
> + case ISD::SREM:
> + if (!C2.getBoolValue())
> + return SDValue();
> + Outputs.push_back(getConstant(C1.srem(C2), SVT));
> + break;
> + case ISD::AND:
> + Outputs.push_back(getConstant(C1 & C2, SVT));
> + break;
> + case ISD::OR:
> + Outputs.push_back(getConstant(C1 | C2, SVT));
> + break;
> + case ISD::XOR:
> + Outputs.push_back(getConstant(C1 ^ C2, SVT));
> + break;
> + case ISD::SHL:
> + Outputs.push_back(getConstant(C1 << C2, SVT));
> + break;
> + case ISD::SRL:
> + Outputs.push_back(getConstant(C1.lshr(C2), SVT));
> + break;
> + case ISD::SRA:
> + Outputs.push_back(getConstant(C1.ashr(C2), SVT));
> + break;
> + case ISD::ROTL:
> + Outputs.push_back(getConstant(C1.rotl(C2), SVT));
> + break;
> + case ISD::ROTR:
> + Outputs.push_back(getConstant(C1.rotr(C2), SVT));
> + break;
> + default:
> + return SDValue();
> + }
> }
>
> - return SDValue();
> + // Handle the scalar case first.
> + if (Outputs.size() == 1)
> + return Outputs.back();
> +
> + // Otherwise build a big vector out of the scalar elements we
> generated.
> + return getNode(ISD::BUILD_VECTOR, DebugLoc(), VT, Outputs.data(),
> + Outputs.size());
> }
>
> -SDValue SelectionDAG::getNode(unsigned Opcode, DebugLoc DL, EVT VT,
> - SDValue N1, SDValue N2) {
> +SDValue SelectionDAG::getNode(unsigned Opcode, DebugLoc DL, EVT VT,
> SDValue N1,
> + SDValue N2) {
> ConstantSDNode *N1C = dyn_cast<ConstantSDNode>(N1.getNode());
> ConstantSDNode *N2C = dyn_cast<ConstantSDNode>(N2.getNode());
> switch (Opcode) {
> @@ -3013,16 +3086,14 @@ SDValue SelectionDAG::getNode(unsigned O
> }
> }
>
> - if (N1C) {
> - if (N2C) {
> - SDValue SV = FoldConstantArithmetic(Opcode, VT, N1C, N2C);
> - if (SV.getNode()) return SV;
> - } else { // Cannonicalize constant to RHS if commutative
> - if (isCommutativeBinOp(Opcode)) {
> - std::swap(N1C, N2C);
> - std::swap(N1, N2);
> - }
> - }
> + // Perform trivial constant folding.
> + SDValue SV = FoldConstantArithmetic(Opcode, VT, N1.getNode(),
> N2.getNode());
> + if (SV.getNode()) return SV;
> +
> + // Canonicalize constant to RHS if commutative.
> + if (N1C && !N2C && isCommutativeBinOp(Opcode)) {
> + std::swap(N1C, N2C);
> + std::swap(N1, N2);
> }
>
> // Constant fold FP operations.
> @@ -3030,7 +3101,7 @@ SDValue SelectionDAG::getNode(unsigned O
> ConstantFPSDNode *N2CFP =
> dyn_cast<ConstantFPSDNode>(N2.getNode());
> if (N1CFP) {
> if (!N2CFP && isCommutativeBinOp(Opcode)) {
> - // Cannonicalize constant to RHS if commutative
> + // Canonicalize constant to RHS if commutative.
> std::swap(N1CFP, N2CFP);
> std::swap(N1, N2);
> } else if (N2CFP) {
>
> Modified: llvm/trunk/lib/Target/PowerPC/PPCISelLowering.cpp
> URL:
> http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/PowerPC/PPCISelLowering.cpp?rev=174325&r1=174324&r2=174325&view=diff
> ==============================================================================
> --- llvm/trunk/lib/Target/PowerPC/PPCISelLowering.cpp (original)
> +++ llvm/trunk/lib/Target/PowerPC/PPCISelLowering.cpp Mon Feb 4
> 09:19:18 2013
> @@ -5032,9 +5032,14 @@ SDValue PPCTargetLowering::LowerBUILD_VE
> // If this value is in the range [-32,30] and is even, use:
> // tmp = VSPLTI[bhw], result = add tmp, tmp
> if (SextVal >= -32 && SextVal <= 30 && (SextVal & 1) == 0) {
> + // FIXME: This is currently disabled because the ADD will be
> folded back
> + // into an invalid BUILD_VECTOR immediately.
> + return SDValue();
> +#if 0
> SDValue Res = BuildSplatI(SextVal >> 1, SplatSize, MVT::Other,
> DAG, dl);
> Res = DAG.getNode(ISD::ADD, dl, Res.getValueType(), Res, Res);
> return DAG.getNode(ISD::BITCAST, dl, Op.getValueType(), Res);
> +#endif
> }
>
> // If this is 0x8000_0000 x 4, turn into vspltisw + vslw. If it
> is
>
> Modified:
> llvm/trunk/test/CodeGen/PowerPC/2008-07-10-SplatMiscompile.ll
> URL:
> http://llvm.org/viewvc/llvm-project/llvm/trunk/test/CodeGen/PowerPC/2008-07-10-SplatMiscompile.ll?rev=174325&r1=174324&r2=174325&view=diff
> ==============================================================================
> --- llvm/trunk/test/CodeGen/PowerPC/2008-07-10-SplatMiscompile.ll
> (original)
> +++ llvm/trunk/test/CodeGen/PowerPC/2008-07-10-SplatMiscompile.ll Mon
> Feb 4 09:19:18 2013
> @@ -1,5 +1,6 @@
> ; RUN: llc < %s -march=ppc32 -mcpu=g5 | grep vadduhm
> ; RUN: llc < %s -march=ppc32 -mcpu=g5 | grep vsubuhm
> +; XFAIL: *
>
> define <4 x i32> @test() nounwind {
> ret <4 x i32> < i32 4293066722, i32 4293066722, i32 4293066722, i32
> 4293066722>
>
> Modified: llvm/trunk/test/CodeGen/X86/2011-11-30-or.ll
> URL:
> http://llvm.org/viewvc/llvm-project/llvm/trunk/test/CodeGen/X86/2011-11-30-or.ll?rev=174325&r1=174324&r2=174325&view=diff
> ==============================================================================
> --- llvm/trunk/test/CodeGen/X86/2011-11-30-or.ll (original)
> +++ llvm/trunk/test/CodeGen/X86/2011-11-30-or.ll Mon Feb 4 09:19:18
> 2013
> @@ -8,9 +8,9 @@ target triple = "x86_64-apple-macosx10.6
> ; CHECK: pblendvb %xmm1, %xmm2
> ; CHECK: ret
>
> -define void @select_func() {
> +define void @select_func(<8 x i16> %in) {
> entry:
> - %c.lobit.i.i.i = ashr <8 x i16> <i16 17, i16 5, i16 1, i16 15, i16
> 19, i16 15, i16 4, i16 1> , <i16 15, i16 15, i16 15, i16 15, i16 15,
> i16 15, i16 15, i16 15>
> + %c.lobit.i.i.i = ashr <8 x i16> %in, <i16 15, i16 15, i16 15, i16
> 15, i16 15, i16 15, i16 15, i16 15>
> %and.i56.i.i.i = and <8 x i16> %c.lobit.i.i.i, <i16 25, i16 8, i16
> 65, i16 25, i16 8, i16 95, i16 15, i16 45>
> %and.i5.i.i.i = bitcast <8 x i16> %and.i56.i.i.i to <2 x i64>
> %neg.i.i.i.i = xor <8 x i16> %c.lobit.i.i.i, <i16 -1, i16 -1, i16
> -1, i16 -1, i16 -1, i16 -1, i16 -1, i16 -1>
>
> Modified: llvm/trunk/test/CodeGen/X86/blend-msb.ll
> URL:
> http://llvm.org/viewvc/llvm-project/llvm/trunk/test/CodeGen/X86/blend-msb.ll?rev=174325&r1=174324&r2=174325&view=diff
> ==============================================================================
> --- llvm/trunk/test/CodeGen/X86/blend-msb.ll (original)
> +++ llvm/trunk/test/CodeGen/X86/blend-msb.ll Mon Feb 4 09:19:18 2013
> @@ -5,7 +5,8 @@
> ; shifting the needed bit to the MSB, and not using shl+sra.
>
> ;CHECK: vsel_float
> -;CHECK: pslld
> +;CHECK: movl $-2147483648
> +;CHECK-NEXT: movd
> ;CHECK-NEXT: blendvps
> ;CHECK: ret
> define <4 x float> @vsel_float(<4 x float> %v1, <4 x float> %v2) {
> @@ -14,7 +15,8 @@ define <4 x float> @vsel_float(<4 x floa
> }
>
> ;CHECK: vsel_4xi8
> -;CHECK: pslld
> +;CHECK: movl $-2147483648
> +;CHECK-NEXT: movd
> ;CHECK-NEXT: blendvps
> ;CHECK: ret
> define <4 x i8> @vsel_4xi8(<4 x i8> %v1, <4 x i8> %v2) {
>
> Modified: llvm/trunk/test/CodeGen/X86/vector-gep.ll
> URL:
> http://llvm.org/viewvc/llvm-project/llvm/trunk/test/CodeGen/X86/vector-gep.ll?rev=174325&r1=174324&r2=174325&view=diff
> ==============================================================================
> --- llvm/trunk/test/CodeGen/X86/vector-gep.ll (original)
> +++ llvm/trunk/test/CodeGen/X86/vector-gep.ll Mon Feb 4 09:19:18
> 2013
> @@ -8,10 +8,8 @@ entry:
> %vecinit2.i = insertelement <4 x i32*> %vecinit.i, i32* %ptr, i32
> 1
> %vecinit4.i = insertelement <4 x i32*> %vecinit2.i, i32* %ptr, i32
> 2
> %vecinit6.i = insertelement <4 x i32*> %vecinit4.i, i32* %ptr, i32
> 3
> -;CHECK: pslld $2
> ;CHECK: padd
> %A2 = getelementptr <4 x i32*> %vecinit6.i, <4 x i32> <i32 1, i32
> 2, i32 3, i32 4>
> -;CHECK: pslld $2
> ;CHECK: padd
> %A3 = getelementptr <4 x i32*> %A2, <4 x i32> <i32 10, i32 14, i32
> 19, i32 233>
> ret <4 x i32*> %A3
> @@ -21,7 +19,6 @@ entry:
> ;CHECK: AGEP1:
> define i32 @AGEP1(<4 x i32*> %param) nounwind {
> entry:
> -;CHECK: pslld $2
> ;CHECK: padd
> %A2 = getelementptr <4 x i32*> %param, <4 x i32> <i32 1, i32 2,
> i32 3, i32 4>
> %k = extractelement <4 x i32*> %A2, i32 3
>
>
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