[llvm] r364977 - [X86] Add a DAG combine for turning *_extend_vector_inreg+load into an appropriate extload if the load isn't volatile.

Jordan Rupprecht via llvm-commits llvm-commits at lists.llvm.org
Mon Jul 8 16:34:11 PDT 2019


FYI, we're seeing some kinda strange test failures after this patch. I'm
unable to get a reproducer, but it's on some utility code that is (at a
very high level) implementing a vector<bool>-type thing, and is now
returning 0 for some elements that were previously set.

On Tue, Jul 2, 2019 at 4:20 PM Craig Topper via llvm-commits <
llvm-commits at lists.llvm.org> wrote:

> Author: ctopper
> Date: Tue Jul  2 16:20:03 2019
> New Revision: 364977
>
> URL: http://llvm.org/viewvc/llvm-project?rev=364977&view=rev
> Log:
> [X86] Add a DAG combine for turning *_extend_vector_inreg+load into an
> appropriate extload if the load isn't volatile.
>
> Remove the corresponding isel patterns that did the same thing without
> checking for volatile.
>
> This fixes another variation of PR42079
>
> Modified:
>     llvm/trunk/lib/Target/X86/X86ISelLowering.cpp
>     llvm/trunk/lib/Target/X86/X86InstrAVX512.td
>     llvm/trunk/lib/Target/X86/X86InstrSSE.td
>
> Modified: llvm/trunk/lib/Target/X86/X86ISelLowering.cpp
> URL:
> http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/X86/X86ISelLowering.cpp?rev=364977&r1=364976&r2=364977&view=diff
>
> ==============================================================================
> --- llvm/trunk/lib/Target/X86/X86ISelLowering.cpp (original)
> +++ llvm/trunk/lib/Target/X86/X86ISelLowering.cpp Tue Jul  2 16:20:03 2019
> @@ -1876,6 +1876,7 @@ X86TargetLowering::X86TargetLowering(con
>    setTargetDAGCombine(ISD::SIGN_EXTEND);
>    setTargetDAGCombine(ISD::SIGN_EXTEND_INREG);
>    setTargetDAGCombine(ISD::ANY_EXTEND_VECTOR_INREG);
> +  setTargetDAGCombine(ISD::SIGN_EXTEND_VECTOR_INREG);
>    setTargetDAGCombine(ISD::ZERO_EXTEND_VECTOR_INREG);
>    setTargetDAGCombine(ISD::SINT_TO_FP);
>    setTargetDAGCombine(ISD::UINT_TO_FP);
> @@ -43914,16 +43915,35 @@ static SDValue combinePMULDQ(SDNode *N,
>  }
>
>  static SDValue combineExtInVec(SDNode *N, SelectionDAG &DAG,
> +                               TargetLowering::DAGCombinerInfo &DCI,
>                                 const X86Subtarget &Subtarget) {
> +  EVT VT = N->getValueType(0);
> +  SDValue In = N->getOperand(0);
> +
> +  // Try to merge vector loads and extend_inreg to an extload.
> +  if (!DCI.isBeforeLegalizeOps() && ISD::isNormalLoad(In.getNode()) &&
> +      In.hasOneUse()) {
> +    auto *Ld = cast<LoadSDNode>(In);
> +    if (!Ld->isVolatile()) {
> +      MVT SVT = In.getSimpleValueType().getVectorElementType();
> +      ISD::LoadExtType Ext = N->getOpcode() ==
> ISD::SIGN_EXTEND_VECTOR_INREG ? ISD::SEXTLOAD : ISD::ZEXTLOAD;
> +      EVT MemVT = EVT::getVectorVT(*DAG.getContext(), SVT,
> +                                   VT.getVectorNumElements());
> +      SDValue Load =
> +          DAG.getExtLoad(Ext, SDLoc(N), VT, Ld->getChain(),
> Ld->getBasePtr(),
> +                         Ld->getPointerInfo(), MemVT, Ld->getAlignment(),
> +                         Ld->getMemOperand()->getFlags());
> +      DAG.ReplaceAllUsesOfValueWith(SDValue(Ld, 1), Load.getValue(1));
> +      return Load;
> +    }
> +  }
> +
>    // Disabling for widening legalization for now. We can enable if we
> find a
>    // case that needs it. Otherwise it can be deleted when we switch to
>    // widening legalization.
>    if (ExperimentalVectorWideningLegalization)
>      return SDValue();
>
> -  EVT VT = N->getValueType(0);
> -  SDValue In = N->getOperand(0);
> -
>    // Combine (ext_invec (ext_invec X)) -> (ext_invec X)
>    const TargetLowering &TLI = DAG.getTargetLoweringInfo();
>    if (In.getOpcode() == N->getOpcode() &&
> @@ -43932,7 +43952,7 @@ static SDValue combineExtInVec(SDNode *N
>
>    // Attempt to combine as a shuffle.
>    // TODO: SSE41 support
> -  if (Subtarget.hasAVX()) {
> +  if (Subtarget.hasAVX() && N->getOpcode() !=
> ISD::SIGN_EXTEND_VECTOR_INREG) {
>      SDValue Op(N, 0);
>      if (TLI.isTypeLegal(VT) && TLI.isTypeLegal(In.getValueType()))
>        if (SDValue Res = combineX86ShufflesRecursively(Op, DAG, Subtarget))
> @@ -44010,7 +44030,9 @@ SDValue X86TargetLowering::PerformDAGCom
>    case ISD::SIGN_EXTEND:    return combineSext(N, DAG, DCI, Subtarget);
>    case ISD::SIGN_EXTEND_INREG: return combineSignExtendInReg(N, DAG,
> Subtarget);
>    case ISD::ANY_EXTEND_VECTOR_INREG:
> -  case ISD::ZERO_EXTEND_VECTOR_INREG: return combineExtInVec(N, DAG,
> Subtarget);
> +  case ISD::SIGN_EXTEND_VECTOR_INREG:
> +  case ISD::ZERO_EXTEND_VECTOR_INREG: return combineExtInVec(N, DAG, DCI,
> +                                                             Subtarget);
>    case ISD::SETCC:          return combineSetCC(N, DAG, Subtarget);
>    case X86ISD::SETCC:       return combineX86SetCC(N, DAG, Subtarget);
>    case X86ISD::BRCOND:      return combineBrCond(N, DAG, Subtarget);
>
> Modified: llvm/trunk/lib/Target/X86/X86InstrAVX512.td
> URL:
> http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/X86/X86InstrAVX512.td?rev=364977&r1=364976&r2=364977&view=diff
>
> ==============================================================================
> --- llvm/trunk/lib/Target/X86/X86InstrAVX512.td (original)
> +++ llvm/trunk/lib/Target/X86/X86InstrAVX512.td Tue Jul  2 16:20:03 2019
> @@ -9632,21 +9632,15 @@ multiclass AVX512_pmovx_patterns<string
>              (!cast<I>(OpcPrefix#BWZ128rm) addr:$src)>;
>    def : Pat<(v8i16 (InVecOp (v16i8 (vzload_v2i64 addr:$src)))),
>              (!cast<I>(OpcPrefix#BWZ128rm) addr:$src)>;
> -  def : Pat<(v8i16 (InVecOp (loadv16i8 addr:$src))),
> -            (!cast<I>(OpcPrefix#BWZ128rm) addr:$src)>;
>    }
>    let Predicates = [HasVLX] in {
>    def : Pat<(v4i32 (InVecOp (bc_v16i8 (v4i32 (scalar_to_vector (loadi32
> addr:$src)))))),
>              (!cast<I>(OpcPrefix#BDZ128rm) addr:$src)>;
>    def : Pat<(v4i32 (InVecOp (v16i8 (vzload_v4i32 addr:$src)))),
>              (!cast<I>(OpcPrefix#BDZ128rm) addr:$src)>;
> -  def : Pat<(v4i32 (InVecOp (loadv16i8 addr:$src))),
> -            (!cast<I>(OpcPrefix#BDZ128rm) addr:$src)>;
>
>    def : Pat<(v2i64 (InVecOp (bc_v16i8 (v4i32 (scalar_to_vector
> (extloadi32i16 addr:$src)))))),
>              (!cast<I>(OpcPrefix#BQZ128rm) addr:$src)>;
> -  def : Pat<(v2i64 (InVecOp (loadv16i8 addr:$src))),
> -            (!cast<I>(OpcPrefix#BQZ128rm) addr:$src)>;
>
>    def : Pat<(v4i32 (InVecOp (bc_v8i16 (v2i64 (scalar_to_vector (loadi64
> addr:$src)))))),
>              (!cast<I>(OpcPrefix#WDZ128rm) addr:$src)>;
> @@ -9654,15 +9648,11 @@ multiclass AVX512_pmovx_patterns<string
>              (!cast<I>(OpcPrefix#WDZ128rm) addr:$src)>;
>    def : Pat<(v4i32 (InVecOp (v8i16 (vzload_v2i64 addr:$src)))),
>              (!cast<I>(OpcPrefix#WDZ128rm) addr:$src)>;
> -  def : Pat<(v4i32 (InVecOp (loadv8i16 addr:$src))),
> -            (!cast<I>(OpcPrefix#WDZ128rm) addr:$src)>;
>
>    def : Pat<(v2i64 (InVecOp (bc_v8i16 (v4i32 (scalar_to_vector (loadi32
> addr:$src)))))),
>              (!cast<I>(OpcPrefix#WQZ128rm) addr:$src)>;
>    def : Pat<(v2i64 (InVecOp (v8i16 (vzload_v4i32 addr:$src)))),
>              (!cast<I>(OpcPrefix#WQZ128rm) addr:$src)>;
> -  def : Pat<(v2i64 (InVecOp (loadv8i16 addr:$src))),
> -            (!cast<I>(OpcPrefix#WQZ128rm) addr:$src)>;
>
>    def : Pat<(v2i64 (InVecOp (bc_v4i32 (v2i64 (scalar_to_vector (loadi64
> addr:$src)))))),
>              (!cast<I>(OpcPrefix#DQZ128rm) addr:$src)>;
> @@ -9670,37 +9660,27 @@ multiclass AVX512_pmovx_patterns<string
>              (!cast<I>(OpcPrefix#DQZ128rm) addr:$src)>;
>    def : Pat<(v2i64 (InVecOp (v4i32 (vzload_v2i64 addr:$src)))),
>              (!cast<I>(OpcPrefix#DQZ128rm) addr:$src)>;
> -  def : Pat<(v2i64 (InVecOp (loadv4i32 addr:$src))),
> -            (!cast<I>(OpcPrefix#DQZ128rm) addr:$src)>;
>    }
>    let Predicates = [HasVLX] in {
>    def : Pat<(v8i32 (InVecOp (bc_v16i8 (v2i64 (scalar_to_vector (loadi64
> addr:$src)))))),
>              (!cast<I>(OpcPrefix#BDZ256rm) addr:$src)>;
>    def : Pat<(v8i32 (InVecOp (v16i8 (vzload_v2i64 addr:$src)))),
>              (!cast<I>(OpcPrefix#BDZ256rm) addr:$src)>;
> -  def : Pat<(v8i32 (InVecOp (loadv16i8 addr:$src))),
> -            (!cast<I>(OpcPrefix#BDZ256rm) addr:$src)>;
>
>    def : Pat<(v4i64 (InVecOp (bc_v16i8 (v4i32 (scalar_to_vector (loadi32
> addr:$src)))))),
>              (!cast<I>(OpcPrefix#BQZ256rm) addr:$src)>;
>    def : Pat<(v4i64 (InVecOp (v16i8 (vzload_v4i32 addr:$src)))),
>              (!cast<I>(OpcPrefix#BQZ256rm) addr:$src)>;
> -  def : Pat<(v4i64 (InVecOp (loadv16i8 addr:$src))),
> -            (!cast<I>(OpcPrefix#BQZ256rm) addr:$src)>;
>
>    def : Pat<(v4i64 (InVecOp (bc_v8i16 (v2i64 (scalar_to_vector (loadi64
> addr:$src)))))),
>              (!cast<I>(OpcPrefix#WQZ256rm) addr:$src)>;
>    def : Pat<(v4i64 (InVecOp (v8i16 (vzload_v2i64 addr:$src)))),
>              (!cast<I>(OpcPrefix#WQZ256rm) addr:$src)>;
> -  def : Pat<(v4i64 (InVecOp (loadv8i16 addr:$src))),
> -            (!cast<I>(OpcPrefix#WQZ256rm) addr:$src)>;
>    }
>    // 512-bit patterns
>    let Predicates = [HasAVX512] in {
>    def : Pat<(v8i64 (InVecOp (bc_v16i8 (v2i64 (scalar_to_vector (loadi64
> addr:$src)))))),
>              (!cast<I>(OpcPrefix#BQZrm) addr:$src)>;
> -  def : Pat<(v8i64 (InVecOp (loadv16i8 addr:$src))),
> -            (!cast<I>(OpcPrefix#BQZrm) addr:$src)>;
>    }
>  }
>
>
> Modified: llvm/trunk/lib/Target/X86/X86InstrSSE.td
> URL:
> http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/X86/X86InstrSSE.td?rev=364977&r1=364976&r2=364977&view=diff
>
> ==============================================================================
> --- llvm/trunk/lib/Target/X86/X86InstrSSE.td (original)
> +++ llvm/trunk/lib/Target/X86/X86InstrSSE.td Tue Jul  2 16:20:03 2019
> @@ -4947,8 +4947,6 @@ multiclass SS41I_pmovx_avx2_patterns<str
>              (!cast<I>(OpcPrefix#BDYrm) addr:$src)>;
>    def : Pat<(v8i32 (InVecOp (v16i8 (vzload_v2i64 addr:$src)))),
>              (!cast<I>(OpcPrefix#BDYrm) addr:$src)>;
> -  def : Pat<(v8i32 (InVecOp (loadv16i8 addr:$src))),
> -            (!cast<I>(OpcPrefix#BDYrm) addr:$src)>;
>
>    def : Pat<(v4i64 (ExtOp (loadv4i32 addr:$src))),
>              (!cast<I>(OpcPrefix#DQYrm) addr:$src)>;
> @@ -4957,15 +4955,11 @@ multiclass SS41I_pmovx_avx2_patterns<str
>              (!cast<I>(OpcPrefix#BQYrm) addr:$src)>;
>    def : Pat<(v4i64 (InVecOp (v16i8 (vzload_v2i64 addr:$src)))),
>              (!cast<I>(OpcPrefix#BQYrm) addr:$src)>;
> -  def : Pat<(v4i64 (InVecOp (loadv16i8 addr:$src))),
> -            (!cast<I>(OpcPrefix#BQYrm) addr:$src)>;
>
>    def : Pat<(v4i64 (InVecOp (bc_v8i16 (v2i64 (scalar_to_vector (loadi64
> addr:$src)))))),
>              (!cast<I>(OpcPrefix#WQYrm) addr:$src)>;
>    def : Pat<(v4i64 (InVecOp (v8i16 (vzload_v2i64 addr:$src)))),
>              (!cast<I>(OpcPrefix#WQYrm) addr:$src)>;
> -  def : Pat<(v4i64 (InVecOp (loadv8i16 addr:$src))),
> -            (!cast<I>(OpcPrefix#WQYrm) addr:$src)>;
>    }
>  }
>
>
>
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