Index: llvm/lib/Target/AArch64/AArch64ExpandPseudoInsts.cpp
===================================================================
--- llvm/lib/Target/AArch64/AArch64ExpandPseudoInsts.cpp
+++ llvm/lib/Target/AArch64/AArch64ExpandPseudoInsts.cpp
@@ -467,7 +467,10 @@
     std::tie(PredIdx, DOPIdx, SrcIdx) = std::make_tuple(1, 2, 3);
     break;
   case AArch64::DestructiveUnaryPassthru:
-    std::tie(PredIdx, DOPIdx, SrcIdx) = std::make_tuple(2, 3, 3);
+    if (FalseZero)
+      std::tie(PredIdx, DOPIdx, SrcIdx) = std::make_tuple(2, 0, 3);
+    else
+      std::tie(PredIdx, DOPIdx, SrcIdx) = std::make_tuple(2, 3, 3);
     break;
   case AArch64::DestructiveTernaryCommWithRev:
     std::tie(PredIdx, DOPIdx, SrcIdx, Src2Idx) = std::make_tuple(1, 2, 3, 4);
@@ -1012,8 +1015,8 @@
   int OrigInstr = AArch64::getSVEPseudoMap(MI.getOpcode());
   if (OrigInstr != -1) {
     auto &Orig = TII->get(OrigInstr);
-    if ((Orig.TSFlags & AArch64::DestructiveInstTypeMask)
-           != AArch64::NotDestructive) {
+    if ((Orig.TSFlags & AArch64::DestructiveInstTypeMask) !=
+        AArch64::NotDestructive) {
       return expand_DestructiveOp(MI, MBB, MBBI);
     }
   }
Index: llvm/lib/Target/AArch64/AArch64SVEInstrInfo.td
===================================================================
--- llvm/lib/Target/AArch64/AArch64SVEInstrInfo.td
+++ llvm/lib/Target/AArch64/AArch64SVEInstrInfo.td
@@ -3523,7 +3523,7 @@
 
 let Predicates = [HasSVE2orSME] in {
   // SVE2 floating-point base 2 logarithm as integer
-  defm FLOGB_ZPmZ : sve2_fp_flogb<"flogb", int_aarch64_sve_flogb>;
+  defm FLOGB_ZPmZ : sve2_fp_flogb<"flogb", "FLOGB_ZPZZ", int_aarch64_sve_flogb, DestructiveUnaryPassthru>;
 
   // SVE2 floating-point convert precision
   defm FCVTXNT_ZPmZ : sve2_fp_convert_down_odd_rounding_top<"fcvtxnt", "int_aarch64_sve_fcvtxnt">;
@@ -3565,6 +3565,10 @@
   def EXT_ZZI_B : sve2_int_perm_extract_i_cons<"ext">;
 } // End HasSVE2orSME
 
+let Predicates = [HasSVE2orSME, UseExperimentalZeroingPseudos] in {
+  defm FLOGB_ZPZZ : sve2_fp_un_pred_zeroing_hsd<int_aarch64_sve_flogb>;
+} // End HasSVE2orSME, UseExperimentalZeroingPseudos
+
 let Predicates = [HasSVE2] in {
   // SVE2 non-temporal gather loads
   defm LDNT1SB_ZZR_S : sve2_mem_gldnt_vs_32_ptrs<0b00000, "ldnt1sb", AArch64ldnt1s_gather_z, nxv4i8>;
Index: llvm/lib/Target/AArch64/SVEInstrFormats.td
===================================================================
--- llvm/lib/Target/AArch64/SVEInstrFormats.td
+++ llvm/lib/Target/AArch64/SVEInstrFormats.td
@@ -480,6 +480,11 @@
                                      Operand vt3, Instruction inst>
 : Pat<(vtd (op vt1:$Op1, (vselect vt1:$Op1, vt2:$Op2, (SVEDup0)), (i32 (vt3:$Op3)))),
       (inst $Op1, $Op2, vt3:$Op3)>;
+
+class SVE_2_Op_Pat_Zero<ValueType vtd, SDPatternOperator op, ValueType vt1,
+                   ValueType vt2, Instruction inst>
+   : Pat<(vtd (op (vtd (SVEDup0)), vt1:$Op1, vt2:$Op2)),
+        (inst (IMPLICIT_DEF), $Op1, $Op2)>;
 }
 
 //
@@ -629,9 +634,12 @@
 // Pseudos for passthru operands
 //
 let hasNoSchedulingInfo = 1 in {
-  class PredOneOpPassthruPseudo<string name, ZPRRegOp zprty>
+  class PredOneOpPassthruPseudo<string name, ZPRRegOp zprty,
+                                FalseLanesEnum flags = FalseLanesNone>
   : SVEPseudo2Instr<name, 0>,
-    Pseudo<(outs zprty:$Zd), (ins zprty:$Passthru, PPR3bAny:$Pg, zprty:$Zs), []>;
+    Pseudo<(outs zprty:$Zd), (ins zprty:$Passthru, PPR3bAny:$Pg, zprty:$Zs), []> {
+    let FalseLanes = flags;
+  }
 }
 
 //===----------------------------------------------------------------------===//
@@ -2787,16 +2795,31 @@
   defm : SVE_1_Op_PassthruUndef_Pat<nxv2f64, op, nxv2i1, nxv2f64, !cast<Instruction>(NAME # _UNDEF_D)>;
 }
 
-multiclass sve2_fp_flogb<string asm, SDPatternOperator op> {
-  def _H : sve_fp_2op_p_zd<0b0011010, asm, ZPR16, ZPR16, ElementSizeH>;
-  def _S : sve_fp_2op_p_zd<0b0011100, asm, ZPR32, ZPR32, ElementSizeS>;
-  def _D : sve_fp_2op_p_zd<0b0011110, asm, ZPR64, ZPR64, ElementSizeD>;
+multiclass sve2_fp_flogb<string asm, string Ps, SDPatternOperator op, DestructiveInstTypeEnum flags> {
+  let DestructiveInstType = flags in {
+    def _H : sve_fp_2op_p_zd<0b0011010, asm, ZPR16, ZPR16, ElementSizeH>,
+               SVEPseudo2Instr<Ps # _H, 1>;
+    def _S : sve_fp_2op_p_zd<0b0011100, asm, ZPR32, ZPR32, ElementSizeS>,
+               SVEPseudo2Instr<Ps # _S, 1>;
+    def _D : sve_fp_2op_p_zd<0b0011110, asm, ZPR64, ZPR64, ElementSizeD>,
+               SVEPseudo2Instr<Ps # _D, 1>;
+  }
 
   def : SVE_3_Op_Pat<nxv8i16, op, nxv8i16, nxv8i1, nxv8f16, !cast<Instruction>(NAME # _H)>;
   def : SVE_3_Op_Pat<nxv4i32, op, nxv4i32, nxv4i1, nxv4f32, !cast<Instruction>(NAME # _S)>;
   def : SVE_3_Op_Pat<nxv2i64, op, nxv2i64, nxv2i1, nxv2f64, !cast<Instruction>(NAME # _D)>;
 }
 
+multiclass sve2_fp_un_pred_zeroing_hsd<SDPatternOperator op> {
+  def _ZERO_H : PredOneOpPassthruPseudo<NAME # _H, ZPR16, FalseLanesZero>;
+  def _ZERO_S : PredOneOpPassthruPseudo<NAME # _S, ZPR32, FalseLanesZero>;
+  def _ZERO_D : PredOneOpPassthruPseudo<NAME # _D, ZPR64, FalseLanesZero>;
+
+  def : SVE_2_Op_Pat_Zero<nxv8i16, op, nxv8i1, nxv8f16, !cast<Pseudo>(NAME # _ZERO_H)>;
+  def : SVE_2_Op_Pat_Zero<nxv4i32, op, nxv4i1, nxv4f32, !cast<Pseudo>(NAME # _ZERO_S)>;
+  def : SVE_2_Op_Pat_Zero<nxv2i64, op, nxv2i1, nxv2f64, !cast<Pseudo>(NAME # _ZERO_D)>;
+}
+
 multiclass sve2_fp_convert_down_odd_rounding<string asm, string op> {
   def _DtoS : sve_fp_2op_p_zd<0b0001010, asm, ZPR64, ZPR32, ElementSizeD>;
   def : SVE_3_Op_Pat<nxv4f32, !cast<SDPatternOperator>(op # _f32f64), nxv4f32, nxv2i1, nxv2f64, !cast<Instruction>(NAME # _DtoS)>;
Index: llvm/test/CodeGen/AArch64/sve2-intrinsics-fp-int-binary-logarithm-zeroing.ll
===================================================================
--- /dev/null
+++ llvm/test/CodeGen/AArch64/sve2-intrinsics-fp-int-binary-logarithm-zeroing.ll
@@ -0,0 +1,47 @@
+; NOTE: Assertions have been autogenerated by utils/update_llc_test_checks.py
+; RUN: llc -mtriple=aarch64-linux-gnu -mattr=+sve2 -mattr=+use-experimental-zeroing-pseudos -asm-verbose=1 < %s | FileCheck %s
+
+;
+; FLOGB
+;
+
+; NOTE: The %unused paramter ensures z0 is free, leading to a simpler test.
+define <vscale x 8 x i16> @flogb_f16(<vscale x 8 x i16> %unused, <vscale x 8 x i1> %pg, <vscale x 8 x half> %a) {
+; CHECK-LABEL: flogb_f16:
+; CHECK:       // %bb.0:
+; CHECK-NEXT:    movprfx z0.h, p0/z, z0.h
+; CHECK-NEXT:    flogb z0.h, p0/m, z1.h
+; CHECK-NEXT:    ret
+  %out = call <vscale x 8 x i16> @llvm.aarch64.sve.flogb.nxv8f16(<vscale x 8 x i16> zeroinitializer,
+                                                                 <vscale x 8 x i1> %pg,
+                                                                 <vscale x 8 x half> %a)
+  ret <vscale x 8 x i16> %out
+}
+
+define <vscale x 4 x i32> @flogb_f32(<vscale x 4 x i32> %unused, <vscale x 4 x i1> %pg, <vscale x 4 x float> %a) {
+; CHECK-LABEL: flogb_f32:
+; CHECK:       // %bb.0:
+; CHECK-NEXT:    movprfx z0.s, p0/z, z0.s
+; CHECK-NEXT:    flogb z0.s, p0/m, z1.s
+; CHECK-NEXT:    ret
+  %out = call <vscale x 4 x i32> @llvm.aarch64.sve.flogb.nxv4f32(<vscale x 4 x i32> zeroinitializer,
+                                                                 <vscale x 4 x i1> %pg,
+                                                                 <vscale x 4 x float> %a)
+  ret <vscale x 4 x i32> %out
+}
+
+define <vscale x 2 x i64> @flogb_f64(<vscale x 2 x i64> %unused, <vscale x 2 x i1> %pg, <vscale x 2 x double> %a) {
+; CHECK-LABEL: flogb_f64:
+; CHECK:       // %bb.0:
+; CHECK-NEXT:    movprfx z0.d, p0/z, z0.d
+; CHECK-NEXT:    flogb z0.d, p0/m, z1.d
+; CHECK-NEXT:    ret
+  %out = call <vscale x 2 x i64> @llvm.aarch64.sve.flogb.nxv2f64(<vscale x 2 x i64> zeroinitializer,
+                                                                 <vscale x 2 x i1> %pg,
+                                                                 <vscale x 2 x double> %a)
+  ret <vscale x 2 x i64> %out
+}
+
+declare <vscale x 8 x i16> @llvm.aarch64.sve.flogb.nxv8f16(<vscale x 8 x i16>, <vscale x 8 x i1>, <vscale x 8 x half>)
+declare <vscale x 4 x i32> @llvm.aarch64.sve.flogb.nxv4f32(<vscale x 4 x i32>, <vscale x 4 x i1>, <vscale x 4 x float>)
+declare <vscale x 2 x i64> @llvm.aarch64.sve.flogb.nxv2f64(<vscale x 2 x i64>, <vscale x 2 x i1>, <vscale x 2 x double>)