[AArch64] AArch64TargetLowering::computeKnownBitsForTargetNode - add support for AArch64ISD::MOV/MVN constants

llvm/lib/Target/AArch64/AArch64ISelLowering.cpp

@@ -2619,6 +2619,32 @@ void AArch64TargetLowering::computeKnownBitsForTargetNode(
                                        << Op->getConstantOperandVal(1)));
     break;
   }
+  case AArch64ISD::MOVImsl: {
+    Known = KnownBits::makeConstant(
+        APInt(Known.getBitWidth(), ~(~Op->getConstantOperandVal(0)
+                                     << Op->getConstantOperandVal(1))));
+    break;
+  }
+  case AArch64ISD::MOVIedit: {
+    Known = KnownBits::makeConstant(APInt(
+        Known.getBitWidth(),
+        AArch64_AM::decodeAdvSIMDModImmType10(Op->getConstantOperandVal(0))));
+    break;
+  }
+  case AArch64ISD::MVNIshift: {
+    Known = KnownBits::makeConstant(
+        APInt(Known.getBitWidth(),
+              (~Op->getConstantOperandVal(0) << Op->getConstantOperandVal(1)),
+              /*isSigned*/ false, /*implicitTrunc*/ true));
+    break;
+  }
+  case AArch64ISD::MVNImsl: {
+    Known = KnownBits::makeConstant(
+        APInt(Known.getBitWidth(),
+              ~(Op->getConstantOperandVal(0) << Op->getConstantOperandVal(1)),
+              /*isSigned*/ false, /*implicitTrunc*/ true));
+    break;
+  }
   case AArch64ISD::LOADgot:
   case AArch64ISD::ADDlow: {
     if (!Subtarget->isTargetILP32())
@@ -30637,6 +30663,16 @@ bool AArch64TargetLowering::isTargetCanonicalConstantNode(SDValue Op) const {
   return Op.getOpcode() == AArch64ISD::DUP ||
          Op.getOpcode() == AArch64ISD::MOVI ||
          Op.getOpcode() == AArch64ISD::MOVIshift ||
+         Op.getOpcode() == AArch64ISD::MOVImsl ||
+         Op.getOpcode() == AArch64ISD::MOVIedit ||
+         Op.getOpcode() == AArch64ISD::MVNIshift ||
+         Op.getOpcode() == AArch64ISD::MVNImsl ||
+         // Ignoring fneg(movi(0)), because if it is folded to FPConstant(-0.0),
+         // ISel will select fmov(mov i64 0x8000000000000000), resulting in a
+         // fmov from fpr to gpr, which is more expensive than fneg(movi(0))
+         (Op.getOpcode() == ISD::FNEG &&
+          Op.getOperand(0).getOpcode() == AArch64ISD::MOVIedit &&
+          Op.getOperand(0).getConstantOperandVal(0) == 0) ||
          (Op.getOpcode() == ISD::EXTRACT_SUBVECTOR &&
           Op.getOperand(0).getOpcode() == AArch64ISD::DUP) ||
          TargetLowering::isTargetCanonicalConstantNode(Op);

llvm/unittests/Target/AArch64/AArch64SelectionDAGTest.cpp

@@ -318,6 +318,118 @@ TEST_F(AArch64SelectionDAGTest, ComputeKnownBits_UADDO_CARRY) {
   EXPECT_EQ(Known.One, APInt(8, 0x86));
 }
 
+// Piggy-backing on the AArch64 tests to verify SelectionDAG::computeKnownBits.
+TEST_F(AArch64SelectionDAGTest, ComputeKnownBits_MOVI) {
+  SDLoc Loc;
+  auto IntSca32VT = MVT::i32;
+  auto Int8Vec8VT = MVT::v8i8;
+  auto Int16Vec8VT = MVT::v16i8;
+  auto Int4Vec16VT = MVT::v4i16;
+  auto Int8Vec16VT = MVT::v8i16;
+  auto Int2Vec32VT = MVT::v2i32;
+  auto Int4Vec32VT = MVT::v4i32;
+  auto IntVec64VT = MVT::v1i64;
+  auto Int2Vec64VT = MVT::v2i64;
+  auto N0 = DAG->getConstant(0x000000A5, Loc, IntSca32VT);
+  KnownBits Known;
+
+  auto OpMOVIedit64 = DAG->getNode(AArch64ISD::MOVIedit, Loc, IntVec64VT, N0);
+  Known = DAG->computeKnownBits(OpMOVIedit64);
+  EXPECT_EQ(Known.Zero, APInt(64, 0x00FF00FFFF00FF00));
+  EXPECT_EQ(Known.One, APInt(64, 0xFF00FF0000FF00FF));
+
+  auto OpMOVIedit128 = DAG->getNode(AArch64ISD::MOVIedit, Loc, Int2Vec64VT, N0);
+  Known = DAG->computeKnownBits(OpMOVIedit128);
+  EXPECT_EQ(Known.Zero, APInt(64, 0x00FF00FFFF00FF00));
+  EXPECT_EQ(Known.One, APInt(64, 0xFF00FF0000FF00FF));
+
+  auto N1 = DAG->getConstant(264, Loc, IntSca32VT);
+  auto OpMOVImsl64 =
+      DAG->getNode(AArch64ISD::MOVImsl, Loc, Int2Vec32VT, N0, N1);
+  Known = DAG->computeKnownBits(OpMOVImsl64);
+  EXPECT_EQ(Known.Zero, APInt(32, 0xFFFF5A00));
+  EXPECT_EQ(Known.One, APInt(32, 0x0000A5FF));
+
+  auto N2 = DAG->getConstant(272, Loc, IntSca32VT);
+  auto OpMOVImsl128 =
+      DAG->getNode(AArch64ISD::MOVImsl, Loc, Int4Vec32VT, N0, N2);
+  Known = DAG->computeKnownBits(OpMOVImsl128);
+  EXPECT_EQ(Known.Zero, APInt(32, 0xFF5A0000));
+  EXPECT_EQ(Known.One, APInt(32, 0x00A5FFFF));
+
+  auto OpMVNImsl64 =
+      DAG->getNode(AArch64ISD::MVNImsl, Loc, Int2Vec32VT, N0, N2);
+  Known = DAG->computeKnownBits(OpMVNImsl64);
+  EXPECT_EQ(Known.Zero, APInt(32, 0x00A50000));
+  EXPECT_EQ(Known.One, APInt(32, 0xFF5AFFFF));
+
+  auto OpMVNImsl128 =
+      DAG->getNode(AArch64ISD::MVNImsl, Loc, Int4Vec32VT, N0, N1);
+  Known = DAG->computeKnownBits(OpMVNImsl128);
+  EXPECT_EQ(Known.Zero, APInt(32, 0x0000A500));
+  EXPECT_EQ(Known.One, APInt(32, 0xFFFF5AFF));
+
+  auto N3 = DAG->getConstant(0, Loc, IntSca32VT);
+  auto OpMOVIshift2Vec32 =
+      DAG->getNode(AArch64ISD::MOVIshift, Loc, Int2Vec32VT, N0, N3);
+  Known = DAG->computeKnownBits(OpMOVIshift2Vec32);
+  EXPECT_EQ(Known.Zero, APInt(32, 0xFFFFFF5A));
+  EXPECT_EQ(Known.One, APInt(32, 0x000000A5));
+
+  auto N4 = DAG->getConstant(24, Loc, IntSca32VT);
+  auto OpMOVIshift4Vec32 =
+      DAG->getNode(AArch64ISD::MOVIshift, Loc, Int4Vec32VT, N0, N4);
+  Known = DAG->computeKnownBits(OpMOVIshift4Vec32);
+  EXPECT_EQ(Known.Zero, APInt(32, 0x5AFFFFFF));
+  EXPECT_EQ(Known.One, APInt(32, 0xA5000000));
+
+  auto OpMVNIshift2Vec32 =
+      DAG->getNode(AArch64ISD::MVNIshift, Loc, Int2Vec32VT, N0, N4);
+  Known = DAG->computeKnownBits(OpMVNIshift2Vec32);
+  EXPECT_EQ(Known.Zero, APInt(32, 0xA5FFFFFF));
+  EXPECT_EQ(Known.One, APInt(32, 0x5A000000));
+
+  auto OpMVNIshift4Vec32 =
+      DAG->getNode(AArch64ISD::MVNIshift, Loc, Int4Vec32VT, N0, N3);
+  Known = DAG->computeKnownBits(OpMVNIshift4Vec32);
+  EXPECT_EQ(Known.Zero, APInt(32, 0x000000A5));
+  EXPECT_EQ(Known.One, APInt(32, 0xFFFFFF5A));
+
+  auto OpMOVIshift4Vec16 =
+      DAG->getNode(AArch64ISD::MOVIshift, Loc, Int4Vec16VT, N0, N3);
+  Known = DAG->computeKnownBits(OpMOVIshift4Vec16);
+  EXPECT_EQ(Known.One, APInt(16, 0x00A5));
+  EXPECT_EQ(Known.Zero, APInt(16, 0xFF5A));
+
+  auto OpMOVIshift8Vec16 =
+      DAG->getNode(AArch64ISD::MOVIshift, Loc, Int8Vec16VT, N0, N1);
+  Known = DAG->computeKnownBits(OpMOVIshift8Vec16);
+  EXPECT_EQ(Known.One, APInt(16, 0xA500));
+  EXPECT_EQ(Known.Zero, APInt(16, 0x5AFF));
+
+  auto OpMVNIshift4Vec16 =
+      DAG->getNode(AArch64ISD::MVNIshift, Loc, Int4Vec16VT, N0, N1);
+  Known = DAG->computeKnownBits(OpMVNIshift4Vec16);
+  EXPECT_EQ(Known.Zero, APInt(16, 0xA5FF));
+  EXPECT_EQ(Known.One, APInt(16, 0x5A00));
+
+  auto OpMVNIshift8Vec16 =
+      DAG->getNode(AArch64ISD::MVNIshift, Loc, Int8Vec16VT, N0, N3);
+  Known = DAG->computeKnownBits(OpMVNIshift8Vec16);
+  EXPECT_EQ(Known.Zero, APInt(16, 0x00A5));
+  EXPECT_EQ(Known.One, APInt(16, 0xFF5A));
+
+  auto OpMOVI8Vec8 = DAG->getNode(AArch64ISD::MOVI, Loc, Int8Vec8VT, N0);
+  Known = DAG->computeKnownBits(OpMOVI8Vec8);
+  EXPECT_EQ(Known.Zero, APInt(8, 0x5A));
+  EXPECT_EQ(Known.One, APInt(8, 0xA5));
+
+  auto OpMOVI16Vec8 = DAG->getNode(AArch64ISD::MOVI, Loc, Int16Vec8VT, N0);
+  Known = DAG->computeKnownBits(OpMOVI16Vec8);
+  EXPECT_EQ(Known.Zero, APInt(8, 0x5A));
+  EXPECT_EQ(Known.One, APInt(8, 0xA5));
+}
+
 // Piggy-backing on the AArch64 tests to verify SelectionDAG::computeKnownBits.
 TEST_F(AArch64SelectionDAGTest, ComputeKnownBits_SUB) {
   SDLoc Loc;