diff --git a/llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp b/llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
--- a/llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
+++ b/llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
@@ -2275,11 +2275,7 @@
 /// for bits that V cannot have.
 bool SelectionDAG::MaskedValueIsZero(SDValue V, const APInt &Mask,
                                      unsigned Depth) const {
-  EVT VT = V.getValueType();
-  APInt DemandedElts = VT.isVector()
-                           ? APInt::getAllOnesValue(VT.getVectorNumElements())
-                           : APInt(1, 1);
-  return MaskedValueIsZero(V, Mask, DemandedElts, Depth);
+  return Mask.isSubsetOf(computeKnownBits(V, Depth).Zero);
 }
 
 /// MaskedValueIsZero - Return true if 'V & Mask' is known to be zero in
@@ -2548,6 +2544,14 @@
 /// every vector element.
 KnownBits SelectionDAG::computeKnownBits(SDValue Op, unsigned Depth) const {
   EVT VT = Op.getValueType();
+
+  // TOOD: Until we have a plan for how to represent demanded elements for
+  // scalable vectors, we can just bail out for now.
+  if (Op.getValueType().isScalableVector()) {
+    unsigned BitWidth = Op.getScalarValueSizeInBits();
+    return KnownBits(BitWidth);
+  }
+
   APInt DemandedElts = VT.isVector()
                            ? APInt::getAllOnesValue(VT.getVectorNumElements())
                            : APInt(1, 1);
@@ -2563,6 +2567,11 @@
 
   KnownBits Known(BitWidth);   // Don't know anything.
 
+  // TOOD: Until we have a plan for how to represent demanded elements for
+  // scalable vectors, we can just bail out for now.
+  if (Op.getValueType().isScalableVector())
+    return Known;
+
   if (auto *C = dyn_cast<ConstantSDNode>(Op)) {
     // We know all of the bits for a constant!
     Known.One = C->getAPIntValue();
diff --git a/llvm/test/CodeGen/AArch64/sve-intrinsics-gather-prefetches-scalar-base-vector-indexes.ll b/llvm/test/CodeGen/AArch64/sve-intrinsics-gather-prefetches-scalar-base-vector-indexes.ll
--- a/llvm/test/CodeGen/AArch64/sve-intrinsics-gather-prefetches-scalar-base-vector-indexes.ll
+++ b/llvm/test/CodeGen/AArch64/sve-intrinsics-gather-prefetches-scalar-base-vector-indexes.ll
@@ -1,4 +1,7 @@
-; RUN: llc -mtriple=aarch64--linux-gnu -mattr=+sve --asm-verbose=false < %s | FileCheck %s
+; RUN: llc -mtriple=aarch64--linux-gnu -mattr=+sve --asm-verbose=false < %s 2>%t | FileCheck %s
+; RUN: FileCheck --check-prefix=WARN --allow-empty %s <%t
+
+; WARN-NOT: warning
 
 ; PRFB <prfop>, <Pg>, [<Xn|SP>, <Zm>.S, <mod>]    -> 32-bit indexes
 define void @llvm_aarch64_sve_prfb_gather_uxtw_index_nx4vi32(<vscale x 4 x i1> %Pg, i8* %base, <vscale x 4 x i32> %indexes) nounwind {
diff --git a/llvm/test/CodeGen/AArch64/sve-intrinsics-ld1ro.ll b/llvm/test/CodeGen/AArch64/sve-intrinsics-ld1ro.ll
--- a/llvm/test/CodeGen/AArch64/sve-intrinsics-ld1ro.ll
+++ b/llvm/test/CodeGen/AArch64/sve-intrinsics-ld1ro.ll
@@ -1,4 +1,7 @@
-; RUN: llc -mtriple=aarch64-linux-gnu -mattr=+sve,+f64mm -asm-verbose=0 < %s | FileCheck %s
+; RUN: llc -mtriple=aarch64-linux-gnu -mattr=+sve,+f64mm -asm-verbose=0 < %s 2>%t | FileCheck %s
+; RUN: FileCheck --check-prefix=WARN --allow-empty %s <%t
+
+; WARN-NOT: warning
 
 ;
 ; LD1ROB
diff --git a/llvm/test/CodeGen/AArch64/sve-intrinsics-scatter-stores-32bit-scaled-offsets.ll b/llvm/test/CodeGen/AArch64/sve-intrinsics-scatter-stores-32bit-scaled-offsets.ll
--- a/llvm/test/CodeGen/AArch64/sve-intrinsics-scatter-stores-32bit-scaled-offsets.ll
+++ b/llvm/test/CodeGen/AArch64/sve-intrinsics-scatter-stores-32bit-scaled-offsets.ll
@@ -1,4 +1,7 @@
-; RUN: llc -mtriple=aarch64-linux-gnu -mattr=+sve < %s | FileCheck %s
+; RUN: llc -mtriple=aarch64-linux-gnu -mattr=+sve < %s 2>%t | FileCheck %s
+; RUN: FileCheck --check-prefix=WARN --allow-empty %s <%t
+
+; WARN-NOT: warning
 
 ;
 ; ST1H, ST1W, ST1D: base + 32-bit scaled offset, sign (sxtw) or zero
diff --git a/llvm/test/CodeGen/AArch64/sve-intrinsics-scatter-stores-32bit-unscaled-offsets.ll b/llvm/test/CodeGen/AArch64/sve-intrinsics-scatter-stores-32bit-unscaled-offsets.ll
--- a/llvm/test/CodeGen/AArch64/sve-intrinsics-scatter-stores-32bit-unscaled-offsets.ll
+++ b/llvm/test/CodeGen/AArch64/sve-intrinsics-scatter-stores-32bit-unscaled-offsets.ll
@@ -1,4 +1,7 @@
-; RUN: llc -mtriple=aarch64-linux-gnu -mattr=+sve < %s | FileCheck %s
+; RUN: llc -mtriple=aarch64-linux-gnu -mattr=+sve < %s 2>%t | FileCheck %s
+; RUN: FileCheck --check-prefix=WARN --allow-empty %s <%t
+
+; WARN-NOT: warning
 
 ;
 ; ST1B, ST1W, ST1H, ST1D: base + 32-bit unscaled offset, sign (sxtw) or zero
diff --git a/llvm/test/CodeGen/AArch64/sve-masked-ldst-nonext.ll b/llvm/test/CodeGen/AArch64/sve-masked-ldst-nonext.ll
--- a/llvm/test/CodeGen/AArch64/sve-masked-ldst-nonext.ll
+++ b/llvm/test/CodeGen/AArch64/sve-masked-ldst-nonext.ll
@@ -1,4 +1,7 @@
-; RUN: llc -mtriple=aarch64--linux-gnu -mattr=+sve -asm-verbose=0 < %s | FileCheck %s
+; RUN: llc -mtriple=aarch64--linux-gnu -mattr=+sve -asm-verbose=0 < %s 2>%t | FileCheck %s
+; RUN: FileCheck --check-prefix=WARN --allow-empty %s <%t
+
+; WARN-NOT: warning
 
 ;
 ; Masked Loads
diff --git a/llvm/test/CodeGen/AArch64/sve-masked-ldst-sext.ll b/llvm/test/CodeGen/AArch64/sve-masked-ldst-sext.ll
--- a/llvm/test/CodeGen/AArch64/sve-masked-ldst-sext.ll
+++ b/llvm/test/CodeGen/AArch64/sve-masked-ldst-sext.ll
@@ -1,4 +1,7 @@
-; RUN: llc -mtriple=aarch64--linux-gnu -mattr=+sve < %s | FileCheck %s
+; RUN: llc -mtriple=aarch64--linux-gnu -mattr=+sve < %s 2>%t | FileCheck %s
+; RUN: FileCheck --check-prefix=WARN --allow-empty %s <%t
+
+; WARN-NOT: warning
 
 ;
 ; Masked Loads
diff --git a/llvm/test/CodeGen/AArch64/sve-masked-ldst-trunc.ll b/llvm/test/CodeGen/AArch64/sve-masked-ldst-trunc.ll
--- a/llvm/test/CodeGen/AArch64/sve-masked-ldst-trunc.ll
+++ b/llvm/test/CodeGen/AArch64/sve-masked-ldst-trunc.ll
@@ -1,4 +1,7 @@
-; RUN: llc -mtriple=aarch64--linux-gnu -mattr=+sve -asm-verbose=0 < %s | FileCheck %s
+; RUN: llc -mtriple=aarch64--linux-gnu -mattr=+sve -asm-verbose=0 < %s 2>%t | FileCheck %s
+; RUN: FileCheck --check-prefix=WARN --allow-empty %s <%t
+
+; WARN-NOT: warning
 
 ;
 ; Masked Stores
diff --git a/llvm/test/CodeGen/AArch64/sve-masked-ldst-zext.ll b/llvm/test/CodeGen/AArch64/sve-masked-ldst-zext.ll
--- a/llvm/test/CodeGen/AArch64/sve-masked-ldst-zext.ll
+++ b/llvm/test/CodeGen/AArch64/sve-masked-ldst-zext.ll
@@ -1,4 +1,7 @@
-; RUN: llc -mtriple=aarch64--linux-gnu -mattr=+sve < %s | FileCheck %s
+; RUN: llc -mtriple=aarch64--linux-gnu -mattr=+sve < %s 2>%t | FileCheck %s
+; RUN: FileCheck --check-prefix=WARN --allow-empty %s <%t
+
+; WARN-NOT: warning
 
 ;
 ; Masked Loads
diff --git a/llvm/test/CodeGen/AArch64/sve-pred-contiguous-ldst-addressing-mode-reg-imm.ll b/llvm/test/CodeGen/AArch64/sve-pred-contiguous-ldst-addressing-mode-reg-imm.ll
--- a/llvm/test/CodeGen/AArch64/sve-pred-contiguous-ldst-addressing-mode-reg-imm.ll
+++ b/llvm/test/CodeGen/AArch64/sve-pred-contiguous-ldst-addressing-mode-reg-imm.ll
@@ -1,4 +1,7 @@
-; RUN: llc -mtriple=aarch64--linux-gnu -mattr=+sve --asm-verbose=false < %s | FileCheck %s
+; RUN: llc -mtriple=aarch64--linux-gnu -mattr=+sve --asm-verbose=false < %s 2>%t | FileCheck %s
+; RUN: FileCheck --check-prefix=WARN --allow-empty %s <%t
+
+; WARN-NOT: warning
 
 ; Range checks: for all the instruction tested in this file, the
 ; immediate must be within the range [-8, 7] (4-bit immediate). Out of
diff --git a/llvm/test/CodeGen/AArch64/sve-pred-contiguous-ldst-addressing-mode-reg-reg.ll b/llvm/test/CodeGen/AArch64/sve-pred-contiguous-ldst-addressing-mode-reg-reg.ll
--- a/llvm/test/CodeGen/AArch64/sve-pred-contiguous-ldst-addressing-mode-reg-reg.ll
+++ b/llvm/test/CodeGen/AArch64/sve-pred-contiguous-ldst-addressing-mode-reg-reg.ll
@@ -1,4 +1,7 @@
-; RUN: llc -mtriple=aarch64--linux-gnu -mattr=+sve --asm-verbose=false < %s | FileCheck %s
+; RUN: llc -mtriple=aarch64--linux-gnu -mattr=+sve --asm-verbose=false < %s 2>%t | FileCheck %s
+; RUN: FileCheck --check-prefix=WARN --allow-empty %s <%t
+
+; WARN-NOT: warning
 
 ; 2-lane contiguous load/stores
 
diff --git a/llvm/test/CodeGen/AArch64/sve-setcc.ll b/llvm/test/CodeGen/AArch64/sve-setcc.ll
--- a/llvm/test/CodeGen/AArch64/sve-setcc.ll
+++ b/llvm/test/CodeGen/AArch64/sve-setcc.ll
@@ -1,4 +1,7 @@
-; RUN: llc -mtriple=aarch64--linux-gnu -mattr=+sve < %s | FileCheck %s
+; RUN: llc -mtriple=aarch64--linux-gnu -mattr=+sve < %s 2>%t | FileCheck %s
+; RUN: FileCheck --check-prefix=WARN --allow-empty %s <%t
+
+; WARN-NOT: warning
 
 ; Ensure we use the inverted CC result of SVE compare instructions when branching.
 define void @sve_cmplt_setcc_inverted(<vscale x 8 x i16>* %out, <vscale x 8 x i16> %in, <vscale x 8 x i1> %pg) {
diff --git a/llvm/unittests/CodeGen/AArch64SelectionDAGTest.cpp b/llvm/unittests/CodeGen/AArch64SelectionDAGTest.cpp
--- a/llvm/unittests/CodeGen/AArch64SelectionDAGTest.cpp
+++ b/llvm/unittests/CodeGen/AArch64SelectionDAGTest.cpp
@@ -98,6 +98,25 @@
   EXPECT_TRUE(Known.isZero());
 }
 
+TEST_F(AArch64SelectionDAGTest, computeKnownBitsSVE_ZERO_EXTEND_VECTOR_INREG) {
+  if (!TM)
+    return;
+  SDLoc Loc;
+  auto Int8VT = EVT::getIntegerVT(Context, 8);
+  auto Int16VT = EVT::getIntegerVT(Context, 16);
+  auto InVecVT = EVT::getVectorVT(Context, Int8VT, 4, true);
+  auto OutVecVT = EVT::getVectorVT(Context, Int16VT, 2, true);
+  auto InVec = DAG->getConstant(0, Loc, InVecVT);
+  auto Op = DAG->getNode(ISD::ZERO_EXTEND_VECTOR_INREG, Loc, OutVecVT, InVec);
+  auto DemandedElts = APInt(2, 3);
+  KnownBits Known = DAG->computeKnownBits(Op, DemandedElts);
+
+  // We don't know anything for SVE at the moment.
+  EXPECT_EQ(Known.Zero, APInt(16, 0u));
+  EXPECT_EQ(Known.One, APInt(16, 0u));
+  EXPECT_FALSE(Known.isZero());
+}
+
 TEST_F(AArch64SelectionDAGTest, computeKnownBits_EXTRACT_SUBVECTOR) {
   if (!TM)
     return;