Ignore fneg(-0.0)

ningxinr · ningxinr · commit 38a936b86eb7 · 2025-08-21T10:08:51.000-07:00
diff --git a/llvm/lib/Target/AArch64/AArch64ISelLowering.cpp b/llvm/lib/Target/AArch64/AArch64ISelLowering.cpp
@@ -30667,6 +30667,9 @@ bool AArch64TargetLowering::isTargetCanonicalConstantNode(SDValue Op) const {
          Op.getOpcode() == AArch64ISD::MOVIedit ||
          Op.getOpcode() == AArch64ISD::MVNIshift ||
          Op.getOpcode() == AArch64ISD::MVNImsl ||
+         (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/test/CodeGen/AArch64/urem-vector-lkk.ll b/llvm/test/CodeGen/AArch64/urem-vector-lkk.ll
@@ -8,14 +8,14 @@ define <4 x i16> @fold_urem_vec_1(<4 x i16> %x) {
 ; CHECK-NEXT:    ldr d1, [x8, :lo12:.LCPI0_0]
 ; CHECK-NEXT:    adrp x8, .LCPI0_1
 ; CHECK-NEXT:    ldr d2, [x8, :lo12:.LCPI0_1]
-; CHECK-NEXT:    mov x8, #-9223372036854775808 // =0x8000000000000000
-; CHECK-NEXT:    ushl v1.4h, v0.4h, v1.4h
-; CHECK-NEXT:    fmov d3, x8
 ; CHECK-NEXT:    adrp x8, .LCPI0_2
+; CHECK-NEXT:    ushl v1.4h, v0.4h, v1.4h
 ; CHECK-NEXT:    umull v1.4s, v1.4h, v2.4h
+; CHECK-NEXT:    movi d2, #0000000000000000
 ; CHECK-NEXT:    shrn v1.4h, v1.4s, #16
-; CHECK-NEXT:    sub v2.4h, v0.4h, v1.4h
-; CHECK-NEXT:    umull v2.4s, v2.4h, v3.4h
+; CHECK-NEXT:    fneg d2, d2
+; CHECK-NEXT:    sub v3.4h, v0.4h, v1.4h
+; CHECK-NEXT:    umull v2.4s, v3.4h, v2.4h
 ; CHECK-NEXT:    shrn v2.4h, v2.4s, #16
 ; CHECK-NEXT:    add v1.4h, v2.4h, v1.4h
 ; CHECK-NEXT:    ldr d2, [x8, :lo12:.LCPI0_2]
