[llvm] Revert "[AArch64] AArch64TargetLowering::computeKnownBitsForTargetNode - add support for AArch64ISD::MOV/MVN constants" (PR #155503)

Vitaly Buka via llvm-commits llvm-commits at lists.llvm.org
Tue Aug 26 14:40:18 PDT 2025


https://github.com/vitalybuka created https://github.com/llvm/llvm-project/pull/155503

Reverts llvm/llvm-project#154039, as it breaks bots.


>From 33973f4f937240e523d1413861bd91b00cd89105 Mon Sep 17 00:00:00 2001
From: Vitaly Buka <vitalybuka at gmail.com>
Date: Tue, 26 Aug 2025 14:39:33 -0700
Subject: [PATCH] =?UTF-8?q?Revert=20"[AArch64]=20AArch64TargetLowering::co?=
 =?UTF-8?q?mputeKnownBitsForTargetNode=20-=20add=20=E2=80=A6"?=
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This reverts commit 55f6b294bdd7fa332355d9334bdd81358144ba57.
---
 .../Target/AArch64/AArch64ISelLowering.cpp    |  36 ------
 .../AArch64/AArch64SelectionDAGTest.cpp       | 114 ------------------
 2 files changed, 150 deletions(-)

diff --git a/llvm/lib/Target/AArch64/AArch64ISelLowering.cpp b/llvm/lib/Target/AArch64/AArch64ISelLowering.cpp
index 95a2b54e53a19..29ae2a1e3e72f 100644
--- a/llvm/lib/Target/AArch64/AArch64ISelLowering.cpp
+++ b/llvm/lib/Target/AArch64/AArch64ISelLowering.cpp
@@ -2626,32 +2626,6 @@ 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())
@@ -30672,16 +30646,6 @@ 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);
diff --git a/llvm/unittests/Target/AArch64/AArch64SelectionDAGTest.cpp b/llvm/unittests/Target/AArch64/AArch64SelectionDAGTest.cpp
index 675fdc7b0db3b..f06f03bb35a5d 100644
--- a/llvm/unittests/Target/AArch64/AArch64SelectionDAGTest.cpp
+++ b/llvm/unittests/Target/AArch64/AArch64SelectionDAGTest.cpp
@@ -318,120 +318,6 @@ 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 N165 = DAG->getConstant(0x000000A5, Loc, IntSca32VT);
-  KnownBits Known;
-
-  auto OpMOVIedit64 = DAG->getNode(AArch64ISD::MOVIedit, Loc, IntVec64VT, N165);
-  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, N165);
-  Known = DAG->computeKnownBits(OpMOVIedit128);
-  EXPECT_EQ(Known.Zero, APInt(64, 0x00FF00FFFF00FF00));
-  EXPECT_EQ(Known.One, APInt(64, 0xFF00FF0000FF00FF));
-
-  auto N264 = DAG->getConstant(264, Loc, IntSca32VT);
-  auto OpMOVImsl64 =
-      DAG->getNode(AArch64ISD::MOVImsl, Loc, Int2Vec32VT, N165, N264);
-  Known = DAG->computeKnownBits(OpMOVImsl64);
-  EXPECT_EQ(Known.Zero, APInt(32, 0xFFFF5A00));
-  EXPECT_EQ(Known.One, APInt(32, 0x0000A5FF));
-
-  auto N272 = DAG->getConstant(272, Loc, IntSca32VT);
-  auto OpMOVImsl128 =
-      DAG->getNode(AArch64ISD::MOVImsl, Loc, Int4Vec32VT, N165, N272);
-  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, N165, N272);
-  Known = DAG->computeKnownBits(OpMVNImsl64);
-  EXPECT_EQ(Known.Zero, APInt(32, 0x00A5FFFF));
-  EXPECT_EQ(Known.One, APInt(32, 0xFF5A0000));
-
-  auto OpMVNImsl128 =
-      DAG->getNode(AArch64ISD::MVNImsl, Loc, Int4Vec32VT, N165, N264);
-  Known = DAG->computeKnownBits(OpMVNImsl128);
-  EXPECT_EQ(Known.Zero, APInt(32, 0x0000A5FF));
-  EXPECT_EQ(Known.One, APInt(32, 0xFFFF5A00));
-
-  auto N0 = DAG->getConstant(0, Loc, IntSca32VT);
-  auto OpMOVIshift2Vec32 =
-      DAG->getNode(AArch64ISD::MOVIshift, Loc, Int2Vec32VT, N165, N0);
-  Known = DAG->computeKnownBits(OpMOVIshift2Vec32);
-  EXPECT_EQ(Known.Zero, APInt(32, 0xFFFFFF5A));
-  EXPECT_EQ(Known.One, APInt(32, 0x000000A5));
-
-  auto N24 = DAG->getConstant(24, Loc, IntSca32VT);
-  auto OpMOVIshift4Vec32 =
-      DAG->getNode(AArch64ISD::MOVIshift, Loc, Int4Vec32VT, N165, N24);
-  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, N165, N24);
-  Known = DAG->computeKnownBits(OpMVNIshift2Vec32);
-  EXPECT_EQ(Known.Zero, APInt(32, 0xA5000000));
-  EXPECT_EQ(Known.One, APInt(32, 0x5AFFFFFF));
-
-  auto OpMVNIshift4Vec32 =
-      DAG->getNode(AArch64ISD::MVNIshift, Loc, Int4Vec32VT, N165, N0);
-  Known = DAG->computeKnownBits(OpMVNIshift4Vec32);
-  EXPECT_EQ(Known.Zero, APInt(32, 0x000000A5));
-  EXPECT_EQ(Known.One, APInt(32, 0xFFFFFF5A));
-
-  auto N8 = DAG->getConstant(8, Loc, IntSca32VT);
-  auto OpMOVIshift4Vec16 =
-      DAG->getNode(AArch64ISD::MOVIshift, Loc, Int4Vec16VT, N165, N0);
-  Known = DAG->computeKnownBits(OpMOVIshift4Vec16);
-  EXPECT_EQ(Known.Zero, APInt(16, 0xFF5A));
-  EXPECT_EQ(Known.One, APInt(16, 0x00A5));
-
-  auto OpMOVIshift8Vec16 =
-      DAG->getNode(AArch64ISD::MOVIshift, Loc, Int8Vec16VT, N165, N8);
-  Known = DAG->computeKnownBits(OpMOVIshift8Vec16);
-  EXPECT_EQ(Known.Zero, APInt(16, 0x5AFF));
-  EXPECT_EQ(Known.One, APInt(16, 0xA500));
-
-  auto OpMVNIshift4Vec16 =
-      DAG->getNode(AArch64ISD::MVNIshift, Loc, Int4Vec16VT, N165, N8);
-  Known = DAG->computeKnownBits(OpMVNIshift4Vec16);
-  EXPECT_EQ(Known.Zero, APInt(16, 0xA500));
-  EXPECT_EQ(Known.One, APInt(16, 0x5AFF));
-
-  auto OpMVNIshift8Vec16 =
-      DAG->getNode(AArch64ISD::MVNIshift, Loc, Int8Vec16VT, N165, N0);
-  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, N165);
-  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, N165);
-  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;



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