diff --git a/llvm/lib/Target/AArch64/AArch64ISelLowering.h b/llvm/lib/Target/AArch64/AArch64ISelLowering.h
--- a/llvm/lib/Target/AArch64/AArch64ISelLowering.h
+++ b/llvm/lib/Target/AArch64/AArch64ISelLowering.h
@@ -734,6 +734,18 @@
 
   bool fallBackToDAGISel(const Instruction &Inst) const override;
 
+  bool
+  shouldExpandBuildVectorWithShuffles(EVT VT,
+                                      unsigned DefinedValues) const override;
+
+  /// SVE code generation for fixed length vectors does not custom lower
+  /// BUILD_VECTOR. This makes BUILD_VECTOR legalisation a source of stores to
+  /// merge. However, merging them creates a BUILD_VECTOR that is just as
+  /// illegal as the original, thus leading to an infinite legalisation loop.
+  bool mergeStoresAfterLegalization(EVT VT) const override {
+    return !useSVEForFixedLengthVectors();
+  }
+
 private:
   /// Keep a pointer to the AArch64Subtarget around so that we can
   /// make the right decision when generating code for different targets.
diff --git a/llvm/lib/Target/AArch64/AArch64ISelLowering.cpp b/llvm/lib/Target/AArch64/AArch64ISelLowering.cpp
--- a/llvm/lib/Target/AArch64/AArch64ISelLowering.cpp
+++ b/llvm/lib/Target/AArch64/AArch64ISelLowering.cpp
@@ -3564,6 +3564,16 @@
   }
 }
 
+// VECTOR_SHUFFLE is not legal for vectors bigger than NEON, so we cannot use
+// them to expand BUILD_VECTOR.
+bool AArch64TargetLowering::shouldExpandBuildVectorWithShuffles(
+    EVT VT, unsigned DefinedValues) const {
+  if (useSVEForFixedLengthVectorVT(VT))
+    return false;
+
+  return TargetLowering::shouldExpandBuildVectorWithShuffles(VT, DefinedValues);
+}
+
 bool AArch64TargetLowering::useSVEForFixedLengthVectors() const {
   // Prefer NEON unless larger SVE registers are available.
   return Subtarget->hasSVE() && Subtarget->getMinSVEVectorSizeInBits() >= 256;
diff --git a/llvm/test/CodeGen/AArch64/sve-fixed-length-shuffles.ll b/llvm/test/CodeGen/AArch64/sve-fixed-length-shuffles.ll
--- a/llvm/test/CodeGen/AArch64/sve-fixed-length-shuffles.ll
+++ b/llvm/test/CodeGen/AArch64/sve-fixed-length-shuffles.ll
@@ -3,6 +3,18 @@
 
 target triple = "aarch64-unknown-linux-gnu"
 
+; Currently there is no custom lowering for vector shuffles operating on types
+; bigger than NEON. However, having no support opens us up to a code generator
+; hang when expanding BUILD_VECTOR. Here we just validate the promblematic case
+; successfully exits code generation.
+define void @hang_when_merging_stores_after_legalisation(<8 x i32>* %a, <2 x i32> %b) #0 {
+; CHECK-LABEL: hang_when_merging_stores_after_legalisation:
+  %splat = shufflevector <2 x i32> %b, <2 x i32> undef, <8 x i32> zeroinitializer
+  %interleaved.vec = shufflevector <8 x i32> %splat, <8 x i32> undef, <8 x i32> <i32 0, i32 4, i32 1, i32 5, i32 2, i32 6, i32 3, i32 7>
+  store <8 x i32> %interleaved.vec, <8 x i32>* %a, align 4
+  ret void
+}
+
 ; NOTE: Currently all CONCAT_VECTORS get expanded so there's little point in
 ; validating all combinations of vector type.