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
@@ -963,12 +963,15 @@
           addTypeForFixedLengthSVE(VT);
 
       // 64bit results can mean a bigger than NEON input.
-      for (auto VT : {MVT::v8i8, MVT::v4i16, MVT::v2i32})
+      for (auto VT : {MVT::v8i8, MVT::v4i16})
         setOperationAction(ISD::TRUNCATE, VT, Custom);
+      setOperationAction(ISD::FP_ROUND, MVT::v4f16, Custom);
 
       // 128bit results imply a bigger than NEON input.
       for (auto VT : {MVT::v16i8, MVT::v8i16, MVT::v4i32})
         setOperationAction(ISD::TRUNCATE, VT, Custom);
+      for (auto VT : {MVT::v8f16, MVT::v4f32})
+        setOperationAction(ISD::FP_ROUND, VT, Expand);
     }
   }
 
@@ -2712,13 +2715,19 @@
                                              SelectionDAG &DAG) const {
   bool IsStrict = Op->isStrictFPOpcode();
   SDValue SrcVal = Op.getOperand(IsStrict ? 1 : 0);
-  if (SrcVal.getValueType() != MVT::f128) {
+  EVT SrcVT = SrcVal.getValueType();
+
+  if (SrcVT != MVT::f128) {
+    // Expand cases where the input is a vector bigger than NEON.
+    if (useSVEForFixedLengthVectorVT(SrcVT))
+      return SDValue();
+
     // It's legal except when f128 is involved
     return Op;
   }
 
   RTLIB::Libcall LC;
-  LC = RTLIB::getFPROUND(SrcVal.getValueType(), Op.getValueType());
+  LC = RTLIB::getFPROUND(SrcVT, Op.getValueType());
 
   // FP_ROUND node has a second operand indicating whether it is known to be
   // precise. That doesn't take part in the LibCall so we can't directly use
diff --git a/llvm/test/CodeGen/AArch64/sve-fixed-length-fp-converts.ll b/llvm/test/CodeGen/AArch64/sve-fixed-length-fp-converts.ll
new file mode 100644
--- /dev/null
+++ b/llvm/test/CodeGen/AArch64/sve-fixed-length-fp-converts.ll
@@ -0,0 +1,168 @@
+; RUN: llc -aarch64-sve-vector-bits-min=128  -asm-verbose=0 < %s | FileCheck %s -check-prefix=NO_SVE
+; RUN: llc -aarch64-sve-vector-bits-min=256  -asm-verbose=0 < %s | FileCheck %s -check-prefixes=CHECK
+; RUN: llc -aarch64-sve-vector-bits-min=384  -asm-verbose=0 < %s | FileCheck %s -check-prefixes=CHECK
+; RUN: llc -aarch64-sve-vector-bits-min=512  -asm-verbose=0 < %s | FileCheck %s -check-prefixes=CHECK,VBITS_GE_512
+; RUN: llc -aarch64-sve-vector-bits-min=640  -asm-verbose=0 < %s | FileCheck %s -check-prefixes=CHECK,VBITS_GE_512
+; RUN: llc -aarch64-sve-vector-bits-min=768  -asm-verbose=0 < %s | FileCheck %s -check-prefixes=CHECK,VBITS_GE_512
+; RUN: llc -aarch64-sve-vector-bits-min=896  -asm-verbose=0 < %s | FileCheck %s -check-prefixes=CHECK,VBITS_GE_512
+; RUN: llc -aarch64-sve-vector-bits-min=1024 -asm-verbose=0 < %s | FileCheck %s -check-prefixes=CHECK,VBITS_GE_512,VBITS_GE_1024
+; RUN: llc -aarch64-sve-vector-bits-min=1152 -asm-verbose=0 < %s | FileCheck %s -check-prefixes=CHECK,VBITS_GE_512,VBITS_GE_1024
+; RUN: llc -aarch64-sve-vector-bits-min=1280 -asm-verbose=0 < %s | FileCheck %s -check-prefixes=CHECK,VBITS_GE_512,VBITS_GE_1024
+; RUN: llc -aarch64-sve-vector-bits-min=1408 -asm-verbose=0 < %s | FileCheck %s -check-prefixes=CHECK,VBITS_GE_512,VBITS_GE_1024
+; RUN: llc -aarch64-sve-vector-bits-min=1536 -asm-verbose=0 < %s | FileCheck %s -check-prefixes=CHECK,VBITS_GE_512,VBITS_GE_1024
+; RUN: llc -aarch64-sve-vector-bits-min=1664 -asm-verbose=0 < %s | FileCheck %s -check-prefixes=CHECK,VBITS_GE_512,VBITS_GE_1024
+; RUN: llc -aarch64-sve-vector-bits-min=1792 -asm-verbose=0 < %s | FileCheck %s -check-prefixes=CHECK,VBITS_GE_512,VBITS_GE_1024
+; RUN: llc -aarch64-sve-vector-bits-min=1920 -asm-verbose=0 < %s | FileCheck %s -check-prefixes=CHECK,VBITS_GE_512,VBITS_GE_1024
+; RUN: llc -aarch64-sve-vector-bits-min=2048 -asm-verbose=0 < %s | FileCheck %s -check-prefixes=CHECK,VBITS_GE_512,VBITS_GE_1024,VBITS_GE_2048
+
+target triple = "aarch64-unknown-linux-gnu"
+
+; Don't use SVE when its registers are no bigger than NEON.
+; NO_SVE-NOT: z{0-9}
+
+; NOTE: fptrunc operations bigger than NEON are expanded. These tests just
+; ensure we've correctly set the operation action for fixed length vector types
+; that require SVE. They'll be updated to protect their expected code generation
+; when lowering it implemented.
+
+;
+; fptrunc f32 -> f16
+;
+
+define <8 x half> @fptrunc_v8f32_v8f16(<8 x float>* %in) #0 {
+; CHECK-LABEL: fptrunc_v8f32_v8f16:
+; CHECK-COUNT-8: fcvt h{{[0-9]}}, s{{[0-9]}}
+; CHECK-NOT: fcvt
+; CHECK: ret
+  %a = load <8 x float>, <8 x float>* %in
+  %b = fptrunc <8 x float> %a to <8 x half>
+  ret <8 x half> %b
+}
+
+define void @fptrunc_v16f32_v16f16(<16 x float>* %in, <16 x half>* %out) #0 {
+; CHECK-LABEL: fptrunc_v16f32_v16f16:
+; CHECK-COUNT-16: fcvt h{{[0-9]}}, s{{[0-9]}}
+; CHECK-NOT: fcvt
+; CHECK: ret
+  %a = load <16 x float>, <16 x float>* %in
+  %b = fptrunc <16 x float> %a to <16 x half>
+  store <16 x half> %b, <16 x half>* %out
+  ret void
+}
+
+define void @fptrunc_v32f32_v32f16(<32 x float>* %in, <32 x half>* %out) #0 {
+; CHECK-LABEL: fptrunc_v32f32_v32f16:
+; CHECK-COUNT-32: fcvt h{{[0-9]}}, s{{[0-9]}}
+; CHECK-NOT: fcvt
+; CHECK: ret
+  %a = load <32 x float>, <32 x float>* %in
+  %b = fptrunc <32 x float> %a to <32 x half>
+  store <32 x half> %b, <32 x half>* %out
+  ret void
+}
+
+define void @fptrunc_v64f32_v64f16(<64 x float>* %in, <64 x half>* %out) #0 {
+; CHECK-LABEL: fptrunc_v64f32_v64f16:
+; CHECK-COUNT-64: fcvt h{{[0-9]}}, s{{[0-9]}}
+; CHECK-NOT: fcvt
+; CHECK: ret
+  %a = load <64 x float>, <64 x float>* %in
+  %b = fptrunc <64 x float> %a to <64 x half>
+  store <64 x half> %b, <64 x half>* %out
+  ret void
+}
+
+;
+; fptrunc f64 -> f16
+;
+
+define <4 x half> @fptrunc_v4f64_v4f16(<4 x double>* %in) #0 {
+; CHECK-LABEL: fptrunc_v4f64_v4f16:
+; CHECK-COUNT-4: fcvt h{{[0-9]}}, d{{[0-9]}}
+; CHECK-NOT: fcvt
+; CHECK: ret
+  %a = load <4 x double>, <4 x double>* %in
+  %b = fptrunc <4 x double> %a to <4 x half>
+  ret <4 x half> %b
+}
+
+define <8 x half> @fptrunc_v8f64_v8f16(<8 x double>* %in) #0 {
+; CHECK-LABEL: fptrunc_v8f64_v8f16:
+; CHECK-COUNT-8: fcvt h{{[0-9]}}, d{{[0-9]}}
+; CHECK-NOT: fcvt
+; CHECK: ret
+  %a = load <8 x double>, <8 x double>* %in
+  %b = fptrunc <8 x double> %a to <8 x half>
+  ret <8 x half> %b
+}
+
+define void @fptrunc_v16f64_v16f16(<16 x double>* %in, <16 x half>* %out) #0 {
+; CHECK-LABEL: fptrunc_v16f64_v16f16:
+; CHECK-COUNT-16: fcvt h{{[0-9]}}, d{{[0-9]}}
+; CHECK-NOT: fcvt
+; CHECK: ret
+  %a = load <16 x double>, <16 x double>* %in
+  %b = fptrunc <16 x double> %a to <16 x half>
+  store <16 x half> %b, <16 x half>* %out
+  ret void
+}
+
+define void @fptrunc_v32f64_v32f16(<32 x double>* %in, <32 x half>* %out) #0 {
+; CHECK-LABEL: fptrunc_v32f64_v32f16:
+; CHECK-COUNT-32: fcvt h{{[0-9]}}, d{{[0-9]}}
+; CHECK-NOT: fcvt
+; CHECK: ret
+  %a = load <32 x double>, <32 x double>* %in
+  %b = fptrunc <32 x double> %a to <32 x half>
+  store <32 x half> %b, <32 x half>* %out
+  ret void
+}
+
+;
+; fptrunc f64 -> f32
+;
+
+define <4 x float> @fptrunc_v4f64_v4f32(<4 x double>* %in) #0 {
+; CHECK-LABEL: fptrunc_v4f64_v4f32:
+; CHECK-COUNT-4: fcvt s{{[0-9]}}, d{{[0-9]}}
+; CHECK-NOT: fcvt
+; CHECK: ret
+  %a = load <4 x double>, <4 x double>* %in
+  %b = fptrunc <4 x double> %a to <4 x float>
+  ret <4 x float> %b
+}
+
+define void @fptrunc_v8f64_v8f32(<8 x double>* %in, <8 x float>* %out) #0 {
+; CHECK-LABEL: fptrunc_v8f64_v8f32:
+; CHECK-COUNT-8: fcvt s{{[0-9]}}, d{{[0-9]}}
+; CHECK-NOT: fcvt
+; CHECK: ret
+  %a = load <8 x double>, <8 x double>* %in
+  %b = fptrunc <8 x double> %a to <8 x float>
+  store <8 x float> %b, <8 x float>* %out
+  ret void
+}
+
+define void @fptrunc_v16f64_v16f32(<16 x double>* %in, <16 x float>* %out) #0 {
+; CHECK-LABEL: fptrunc_v16f64_v16f32:
+; CHECK-COUNT-16: fcvt s{{[0-9]}}, d{{[0-9]}}
+; CHECK-NOT: fcvt
+; CHECK: ret
+  %a = load <16 x double>, <16 x double>* %in
+  %b = fptrunc <16 x double> %a to <16 x float>
+  store <16 x float> %b, <16 x float>* %out
+  ret void
+}
+
+define void @fptrunc_v32f64_v32f32(<32 x double>* %in, <32 x float>* %out) #0 {
+; CHECK-LABEL: fptrunc_v32f64_v32f32:
+; CHECK-COUNT-32: fcvt s{{[0-9]}}, d{{[0-9]}}
+; CHECK-NOT: fcvt
+; CHECK: ret
+  %a = load <32 x double>, <32 x double>* %in
+  %b = fptrunc <32 x double> %a to <32 x float>
+  store <32 x float> %b, <32 x float>* %out
+  ret void
+}
+
+attributes #0 = { nounwind "target-features"="+sve" }