[mips][msa] Added support for matching bmnz, bmnzi, bmz, and bmzi from normal IR (i.e. not intrinsics)

Also corrected the definition of the intrinsics for these instructions (the
result register is also the first operand), and added intrinsics for bsel and
bseli to clang (they already existed in the backend).

These four operations are mostly equivalent to bsel, and bseli (the difference
is which operand is tied to the result). As a result some of the tests changed
as described below.

bitwise.ll:
- bsel.v test adapted so that the mask is unknown at compile-time. This stops
  it emitting bmnzi.b instead of the intended bsel.v.
- The bseli.b test now tests the right thing. Namely the case when one of the
  values is an uimm8, rather than when the condition is a uimm8 (which is
  covered by bmnzi.b)

compare.ll:
- bsel.v tests now (correctly) emits bmnz.v instead of bsel.v because this
  is the same operation (see MSA.txt).

i8.ll
- CHECK-DAG-ized test.
- bmzi.b test now (correctly) emits equivalent bmnzi.b with swapped operands
  because this is the same operation (see MSA.txt).
- bseli.b still emits bseli.b though because the immediate makes it
  distinguishable from bmnzi.b.

vec.ll:
- CHECK-DAG-ized test.
- bmz.v tests now (correctly) emits bmnz.v with swapped operands (see
  MSA.txt).
- bsel.v tests now (correctly) emits bmnz.v with swapped operands (see
  MSA.txt).



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@193693 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 103 insertions, 5 deletions

diff --git a/lib/Target/Mips/MipsSEISelLowering.cpp b/lib/Target/Mips/MipsSEISelLowering.cpp
index 9c543330cc..c6ca87caa5 100644
--- a/lib/Target/Mips/MipsSEISelLowering.cpp
+++ b/lib/Target/Mips/MipsSEISelLowering.cpp
@@ -516,6 +516,44 @@ static bool isVSplat(SDValue N, APInt &Imm, bool IsLittleEndian) {
   return true;
 }
 
+// Test whether the given node is an all-ones build_vector.
+static bool isVectorAllOnes(SDValue N) {
+  // Look through bitcasts. Endianness doesn't matter because we are looking
+  // for an all-ones value.
+  if (N->getOpcode() == ISD::BITCAST)
+    N = N->getOperand(0);
+
+  BuildVectorSDNode *BVN = dyn_cast<BuildVectorSDNode>(N);
+
+  if (!BVN)
+    return false;
+
+  APInt SplatValue, SplatUndef;
+  unsigned SplatBitSize;
+  bool HasAnyUndefs;
+
+  // Endianness doesn't matter in this context because we are looking for
+  // an all-ones value.
+  if (BVN->isConstantSplat(SplatValue, SplatUndef, SplatBitSize, HasAnyUndefs))
+    return SplatValue.isAllOnesValue();
+
+  return false;
+}
+
+// Test whether N is the bitwise inverse of OfNode.
+static bool isBitwiseInverse(SDValue N, SDValue OfNode) {
+  if (N->getOpcode() != ISD::XOR)
+    return false;
+
+  if (isVectorAllOnes(N->getOperand(0)))
+    return N->getOperand(1) == OfNode;
+
+  if (isVectorAllOnes(N->getOperand(1)))
+    return N->getOperand(0) == OfNode;
+
+  return false;
+}
+
 // Perform combines where ISD::OR is the root node.
 //
 // Performs the following transformations:
@@ -544,6 +582,7 @@ static SDValue performORCombine(SDNode *N, SelectionDAG &DAG,
     bool IsLittleEndian = !Subtarget->isLittle();
 
     SDValue IfSet, IfClr, Cond;
+    bool IsConstantMask = false;
     APInt Mask, InvMask;
 
     // If Op0Op0 is an appropriate mask, try to find it's inverse in either
@@ -558,6 +597,8 @@ static SDValue performORCombine(SDNode *N, SelectionDAG &DAG,
         IfClr = Op1Op1;
       else if (isVSplat(Op1Op1, InvMask, IsLittleEndian) && Mask == ~InvMask)
         IfClr = Op1Op0;
+
+      IsConstantMask = true;
     }
 
     // If IfClr is not yet set, and Op0Op1 is an appropriate mask, try the same
@@ -571,6 +612,47 @@ static SDValue performORCombine(SDNode *N, SelectionDAG &DAG,
         IfClr = Op1Op1;
       else if (isVSplat(Op1Op1, InvMask, IsLittleEndian) && Mask == ~InvMask)
         IfClr = Op1Op0;
+
+      IsConstantMask = true;
+    }
+
+    // If IfClr is not yet set, try looking for a non-constant match.
+    // IfClr will be set if we find a valid match amongst the eight
+    // possibilities.
+    if (!IfClr.getNode()) {
+      if (isBitwiseInverse(Op0Op0, Op1Op0)) {
+        Cond = Op1Op0;
+        IfSet = Op1Op1;
+        IfClr = Op0Op1;
+      } else if (isBitwiseInverse(Op0Op1, Op1Op0)) {
+        Cond = Op1Op0;
+        IfSet = Op1Op1;
+        IfClr = Op0Op0;
+      } else if (isBitwiseInverse(Op0Op0, Op1Op1)) {
+        Cond = Op1Op1;
+        IfSet = Op1Op0;
+        IfClr = Op0Op1;
+      } else if (isBitwiseInverse(Op0Op1, Op1Op1)) {
+        Cond = Op1Op1;
+        IfSet = Op1Op0;
+        IfClr = Op0Op0;
+      } else if (isBitwiseInverse(Op1Op0, Op0Op0)) {
+        Cond = Op0Op0;
+        IfSet = Op0Op1;
+        IfClr = Op1Op1;
+      } else if (isBitwiseInverse(Op1Op1, Op0Op0)) {
+        Cond = Op0Op0;
+        IfSet = Op0Op1;
+        IfClr = Op1Op0;
+      } else if (isBitwiseInverse(Op1Op0, Op0Op1)) {
+        Cond = Op0Op1;
+        IfSet = Op0Op0;
+        IfClr = Op1Op1;
+      } else if (isBitwiseInverse(Op1Op1, Op0Op1)) {
+        Cond = Op0Op1;
+        IfSet = Op0Op0;
+        IfClr = Op1Op0;
+      }
     }
 
     // At this point, IfClr will be set if we have a valid match.
@@ -580,10 +662,12 @@ static SDValue performORCombine(SDNode *N, SelectionDAG &DAG,
     assert(Cond.getNode() && IfSet.getNode());
 
     // Fold degenerate cases.
-    if (Mask.isAllOnesValue())
-      return IfSet;
-    else if (Mask == 0)
-      return IfClr;
+    if (IsConstantMask) {
+      if (Mask.isAllOnesValue())
+        return IfSet;
+      else if (Mask == 0)
+        return IfClr;
+    }
 
     // Transform the DAG into an equivalent VSELECT.
     return DAG.getNode(ISD::VSELECT, SDLoc(N), Ty, Cond, IfClr, IfSet);
@@ -1284,6 +1368,20 @@ SDValue MipsSETargetLowering::lowerINTRINSIC_WO_CHAIN(SDValue Op,
                        DAG.getConstant(Mask, VecTy, true), Op->getOperand(1),
                        Op->getOperand(2));
   }
+  case Intrinsic::mips_bmnz_v:
+    return DAG.getNode(ISD::VSELECT, DL, Op->getValueType(0), Op->getOperand(3),
+                       Op->getOperand(2), Op->getOperand(1));
+  case Intrinsic::mips_bmnzi_b:
+    return DAG.getNode(ISD::VSELECT, DL, Op->getValueType(0),
+                       lowerMSASplatImm(Op, 3, DAG), Op->getOperand(2),
+                       Op->getOperand(1));
+  case Intrinsic::mips_bmz_v:
+    return DAG.getNode(ISD::VSELECT, DL, Op->getValueType(0), Op->getOperand(3),
+                       Op->getOperand(1), Op->getOperand(2));
+  case Intrinsic::mips_bmzi_b:
+    return DAG.getNode(ISD::VSELECT, DL, Op->getValueType(0),
+                       lowerMSASplatImm(Op, 3, DAG), Op->getOperand(1),
+                       Op->getOperand(2));
   case Intrinsic::mips_bnz_b:
   case Intrinsic::mips_bnz_h:
   case Intrinsic::mips_bnz_w:
@@ -1872,7 +1970,7 @@ SDValue MipsSETargetLowering::lowerINTRINSIC_VOID(SDValue Op,
 /// true.
 static bool isSplatVector(const BuildVectorSDNode *N) {
   unsigned int nOps = N->getNumOperands();
-  assert(nOps > 1 && "isSplat has 0 or 1 sized build vector");
+  assert(nOps > 1 && "isSplatVector has 0 or 1 sized build vector");
 
   SDValue Operand0 = N->getOperand(0);