[X86] Move IsElementEquivalent above shuffle comparison helpers. NFC.

No change - but makes it easier for the shuffle helpers to call IsElementEquivalent.

Author: RKSimon

llvm/lib/Target/X86/X86ISelLowering.cpp

@@ -9793,6 +9793,93 @@ static SDValue LowerCONCAT_VECTORS(SDValue Op,
 // patterns.
 //===----------------------------------------------------------------------===//
 
+/// Checks whether the vector elements referenced by two shuffle masks are
+/// equivalent.
+static bool IsElementEquivalent(int MaskSize, SDValue Op, SDValue ExpectedOp,
+                                int Idx, int ExpectedIdx) {
+  assert(0 <= Idx && Idx < MaskSize && 0 <= ExpectedIdx &&
+         ExpectedIdx < MaskSize && "Out of range element index");
+  if (!Op || !ExpectedOp || Op.getOpcode() != ExpectedOp.getOpcode())
+    return false;
+
+  EVT VT = Op.getValueType();
+  switch (Op.getOpcode()) {
+  case ISD::BUILD_VECTOR:
+    // If the values are build vectors, we can look through them to find
+    // equivalent inputs that make the shuffles equivalent.
+    // TODO: Handle MaskSize != Op.getNumOperands()?
+    if (MaskSize == (int)Op.getNumOperands() &&
+        MaskSize == (int)ExpectedOp.getNumOperands())
+      return Op.getOperand(Idx) == ExpectedOp.getOperand(ExpectedIdx);
+    break;
+  case ISD::BITCAST: {
+    SDValue Src = peekThroughBitcasts(Op);
+    EVT SrcVT = Src.getValueType();
+    if (Op == ExpectedOp && SrcVT.isVector() &&
+        (int)VT.getVectorNumElements() == MaskSize) {
+      if ((SrcVT.getScalarSizeInBits() % VT.getScalarSizeInBits()) == 0) {
+        unsigned Scale = SrcVT.getScalarSizeInBits() / VT.getScalarSizeInBits();
+        return (Idx % Scale) == (ExpectedIdx % Scale) &&
+               IsElementEquivalent(SrcVT.getVectorNumElements(), Src, Src,
+                                   Idx / Scale, ExpectedIdx / Scale);
+      }
+      if ((VT.getScalarSizeInBits() % SrcVT.getScalarSizeInBits()) == 0) {
+        unsigned Scale = VT.getScalarSizeInBits() / SrcVT.getScalarSizeInBits();
+        for (unsigned I = 0; I != Scale; ++I)
+          if (!IsElementEquivalent(SrcVT.getVectorNumElements(), Src, Src,
+                                   (Idx * Scale) + I,
+                                   (ExpectedIdx * Scale) + I))
+            return false;
+        return true;
+      }
+    }
+    break;
+  }
+  case ISD::VECTOR_SHUFFLE: {
+    auto *SVN = cast<ShuffleVectorSDNode>(Op);
+    return Op == ExpectedOp && (int)VT.getVectorNumElements() == MaskSize &&
+           SVN->getMaskElt(Idx) == SVN->getMaskElt(ExpectedIdx);
+  }
+  case X86ISD::VBROADCAST:
+  case X86ISD::VBROADCAST_LOAD:
+    // TODO: Handle MaskSize != VT.getVectorNumElements()?
+    return (Op == ExpectedOp && (int)VT.getVectorNumElements() == MaskSize);
+  case X86ISD::SUBV_BROADCAST_LOAD:
+    // TODO: Handle MaskSize != VT.getVectorNumElements()?
+    if (Op == ExpectedOp && (int)VT.getVectorNumElements() == MaskSize) {
+      auto *MemOp = cast<MemSDNode>(Op);
+      unsigned NumMemElts = MemOp->getMemoryVT().getVectorNumElements();
+      return (Idx % NumMemElts) == (ExpectedIdx % NumMemElts);
+    }
+    break;
+  case X86ISD::HADD:
+  case X86ISD::HSUB:
+  case X86ISD::FHADD:
+  case X86ISD::FHSUB:
+  case X86ISD::PACKSS:
+  case X86ISD::PACKUS:
+    // HOP(X,X) can refer to the elt from the lower/upper half of a lane.
+    // TODO: Handle MaskSize != NumElts?
+    // TODO: Handle HOP(X,Y) vs HOP(Y,X) equivalence cases.
+    if (Op == ExpectedOp && Op.getOperand(0) == Op.getOperand(1)) {
+      int NumElts = VT.getVectorNumElements();
+      if (MaskSize == NumElts) {
+        int NumLanes = VT.getSizeInBits() / 128;
+        int NumEltsPerLane = NumElts / NumLanes;
+        int NumHalfEltsPerLane = NumEltsPerLane / 2;
+        bool SameLane =
+            (Idx / NumEltsPerLane) == (ExpectedIdx / NumEltsPerLane);
+        bool SameElt =
+            (Idx % NumHalfEltsPerLane) == (ExpectedIdx % NumHalfEltsPerLane);
+        return SameLane && SameElt;
+      }
+    }
+    break;
+  }
+
+  return false;
+}
+
 /// Tiny helper function to identify a no-op mask.
 ///
 /// This is a somewhat boring predicate function. It checks whether the mask
@@ -9968,93 +10055,6 @@ static bool isRepeatedTargetShuffleMask(unsigned LaneSizeInBits, MVT VT,
                                      Mask, RepeatedMask);
 }
 
-/// Checks whether the vector elements referenced by two shuffle masks are
-/// equivalent.
-static bool IsElementEquivalent(int MaskSize, SDValue Op, SDValue ExpectedOp,
-                                int Idx, int ExpectedIdx) {
-  assert(0 <= Idx && Idx < MaskSize && 0 <= ExpectedIdx &&
-         ExpectedIdx < MaskSize && "Out of range element index");
-  if (!Op || !ExpectedOp || Op.getOpcode() != ExpectedOp.getOpcode())
-    return false;
-
-  EVT VT = Op.getValueType();
-  switch (Op.getOpcode()) {
-  case ISD::BUILD_VECTOR:
-    // If the values are build vectors, we can look through them to find
-    // equivalent inputs that make the shuffles equivalent.
-    // TODO: Handle MaskSize != Op.getNumOperands()?
-    if (MaskSize == (int)Op.getNumOperands() &&
-        MaskSize == (int)ExpectedOp.getNumOperands())
-      return Op.getOperand(Idx) == ExpectedOp.getOperand(ExpectedIdx);
-    break;
-  case ISD::BITCAST: {
-    SDValue Src = peekThroughBitcasts(Op);
-    EVT SrcVT = Src.getValueType();
-    if (Op == ExpectedOp && SrcVT.isVector() &&
-        (int)VT.getVectorNumElements() == MaskSize) {
-      if ((SrcVT.getScalarSizeInBits() % VT.getScalarSizeInBits()) == 0) {
-        unsigned Scale = SrcVT.getScalarSizeInBits() / VT.getScalarSizeInBits();
-        return (Idx % Scale) == (ExpectedIdx % Scale) &&
-               IsElementEquivalent(SrcVT.getVectorNumElements(), Src, Src,
-                                   Idx / Scale, ExpectedIdx / Scale);
-      }
-      if ((VT.getScalarSizeInBits() % SrcVT.getScalarSizeInBits()) == 0) {
-        unsigned Scale = VT.getScalarSizeInBits() / SrcVT.getScalarSizeInBits();
-        for (unsigned I = 0; I != Scale; ++I)
-          if (!IsElementEquivalent(SrcVT.getVectorNumElements(), Src, Src,
-                                   (Idx * Scale) + I,
-                                   (ExpectedIdx * Scale) + I))
-            return false;
-        return true;
-      }
-    }
-    break;
-  }
-  case ISD::VECTOR_SHUFFLE: {
-    auto *SVN = cast<ShuffleVectorSDNode>(Op);
-    return Op == ExpectedOp && (int)VT.getVectorNumElements() == MaskSize &&
-           SVN->getMaskElt(Idx) == SVN->getMaskElt(ExpectedIdx);
-  }
-  case X86ISD::VBROADCAST:
-  case X86ISD::VBROADCAST_LOAD:
-    // TODO: Handle MaskSize != VT.getVectorNumElements()?
-    return (Op == ExpectedOp && (int)VT.getVectorNumElements() == MaskSize);
-  case X86ISD::SUBV_BROADCAST_LOAD:
-    // TODO: Handle MaskSize != VT.getVectorNumElements()?
-    if (Op == ExpectedOp && (int)VT.getVectorNumElements() == MaskSize) {
-      auto *MemOp = cast<MemSDNode>(Op);
-      unsigned NumMemElts = MemOp->getMemoryVT().getVectorNumElements();
-      return (Idx % NumMemElts) == (ExpectedIdx % NumMemElts);
-    }
-    break;
-  case X86ISD::HADD:
-  case X86ISD::HSUB:
-  case X86ISD::FHADD:
-  case X86ISD::FHSUB:
-  case X86ISD::PACKSS:
-  case X86ISD::PACKUS:
-    // HOP(X,X) can refer to the elt from the lower/upper half of a lane.
-    // TODO: Handle MaskSize != NumElts?
-    // TODO: Handle HOP(X,Y) vs HOP(Y,X) equivalence cases.
-    if (Op == ExpectedOp && Op.getOperand(0) == Op.getOperand(1)) {
-      int NumElts = VT.getVectorNumElements();
-      if (MaskSize == NumElts) {
-        int NumLanes = VT.getSizeInBits() / 128;
-        int NumEltsPerLane = NumElts / NumLanes;
-        int NumHalfEltsPerLane = NumEltsPerLane / 2;
-        bool SameLane =
-            (Idx / NumEltsPerLane) == (ExpectedIdx / NumEltsPerLane);
-        bool SameElt =
-            (Idx % NumHalfEltsPerLane) == (ExpectedIdx % NumHalfEltsPerLane);
-        return SameLane && SameElt;
-      }
-    }
-    break;
-  }
-
-  return false;
-}
-
 /// Checks whether a shuffle mask is equivalent to an explicit list of
 /// arguments.
 ///