[ARM,MVE] Add the vmovlbq,vmovltq intrinsic family.

[simon_tatham]

Summary

These intrinsics take a vector of 2n elements, and return a vector of
n wider elements obtained by sign- or zero-extending every other
element of the input vector. They're represented in IR as a
shufflevector that extracts the odd or even elements of the input,
followed by a sext or zext.

Existing LLVM codegen already matches this pattern and generates the
VMOVLB instruction (which widens the even-index input lanes). But no
existing isel rule was generating VMOVLT, so I've added some. However,
the new rules currently only work in little-endian MVE, because the
pattern they expect from isel lowering includes a bitconvert which
doesn't have the right semantics in big-endian.

The output of one existing codegen test is improved by those new
rules.

This commit adds the unpredicated forms only.

[simon_tatham]

Spotted a mistake by myself: one of my new isel patterns was generating signed VMOVL where it should have been generating unsigned. Fixed, and updated the llc test that had the wrong expectation in it.

Also rebased to current master.

[simon_tatham]

Cosmetic tweak: don't put the new arm_mve.td section in between the definition and the uses of an unrelated multiclass.

[dmgreen]

I think these odd shuffle then extend patterns might come up in codegen too, so this looks like a nice change.

LGTM, if the test is just a test case problem.

llvm/lib/Target/ARM/ARMInstrMVE.td

2397

Perhaps move this down to outside of the let Predicates = [HasMVEInt] in block?

I also like it when Pats make it obvious what the input and the output are:

def : Pat<(ARMvbicImm (v8i16 (bitconvert (ARMvrev16 (v16i8 MQPR:$src)))),
                      (i32 0xAFF)),
          (MVE_VMOVLu8th MQPR:$src)>;

Those are just minor Nitpicks though.

llvm/test/CodeGen/Thumb2/mve-shuffleext.ll

40

vmovlt.u16? Does this need updating like the others?

[simon_tatham]

Made the new isel patterns work in big-endian as well as little. Depends on the extra preparatory patch D74716.

[dmgreen]

Nice one.

clang/include/clang/Basic/arm_mve.td

multiclass float_int_conversions<Type FScalar, Type IScalar, IRBuilderBase ftoi, IRBuilderBase itof> {
   let params = [IScalar], pnt = PNT_2Type in
     def : Intrinsic<FVector, (args IVector:$a), (itof $a, FVector)>,
           NameOverride<"vcvtq_" # FScalar>;
   let params = [FScalar], pnt = PNT_None in
     def : Intrinsic<IVector, (args FVector:$a), (ftoi $a, IVector)>,
           NameOverride<"vcvtq_" # IScalar>;
 }
 
+let params = [s8, u8, s16, u16] in {
+  def vmovlbq: Intrinsic<DblVector, (args Vector:$a),
+    (extend (unzip $a, 0), DblVector, (unsignedflag Scalar))>;
+  def vmovltq: Intrinsic<DblVector, (args Vector:$a),
+    (extend (unzip $a, 1), DblVector, (unsignedflag Scalar))>;
+}
+
 defm : float_int_conversions<f32, u32, fptoui, uitofp>;
 defm : float_int_conversions<f16, u16, fptoui, uitofp>;
 defm : float_int_conversions<f32, s32, fptosi, sitofp>;
 defm : float_int_conversions<f16, s16, fptosi, sitofp>;
 
 let params = T.Float in {
   def vrndq: Intrinsic<Vector, (args Vector:$a),
       (IRIntBase<"trunc", [Vector]> $a)>;

clang/include/clang/Basic/arm_mve_defs.td

 def fneg: IRBuilder<"CreateFNeg">;
 def sitofp: IRBuilder<"CreateSIToFP">;
 def uitofp: IRBuilder<"CreateUIToFP">;
 def fptosi: IRBuilder<"CreateFPToSI">;
 def fptoui: IRBuilder<"CreateFPToUI">;
 def vrev: CGHelperFn<"ARMMVEVectorElementReverse"> {
   let special_params = [IRBuilderIntParam<1, "unsigned">];
 }
+def unzip: CGHelperFn<"VectorUnzip"> {
+  let special_params = [IRBuilderIntParam<1, "bool">];
+}
 
 // Helper for making boolean flags in IR
 def i1: IRBuilderBase {
   let prefix = "llvm::ConstantInt::get(Builder.getInt1Ty(), ";
   let special_params = [IRBuilderIntParam<0, "bool">];
 }
 
 // A node that makes an Address out of a pointer-typed Value, by

clang/lib/CodeGen/CGBuiltin.cpp

return Builder.CreateCall(
         CGF->CGM.getIntrinsic(Intrinsic::arm_mve_vreinterpretq,
                               {DestType, V->getType()}),
         V);
   } else {
     return Builder.CreateBitCast(V, DestType);
   }
 }
 
+static llvm::Value *VectorUnzip(CGBuilderTy &Builder, llvm::Value *V, bool Odd) {
+  // Make a shufflevector that extracts every other element of a vector (evens
+  // or odds, as desired).
+  SmallVector<uint32_t, 16> Indices;
+  unsigned InputElements = V->getType()->getVectorNumElements();
+  for (unsigned i = 0; i < InputElements; i += 2)
+    Indices.push_back(i + Odd);
+  return Builder.CreateShuffleVector(V, llvm::UndefValue::get(V->getType()),
+                                     Indices);
+}
+
 template<unsigned HighBit, unsigned OtherBits>
 static llvm::Value *ARMMVEConstantSplat(CGBuilderTy &Builder, llvm::Type *VT) {
   // MVE-specific helper function to make a vector splat of a constant such as
   // UINT_MAX or INT_MIN, in which all bits below the highest one are equal.
   llvm::Type *T = VT->getVectorElementType();
   unsigned LaneBits = T->getPrimitiveSizeInBits();
   uint32_t Value = HighBit << (LaneBits - 1);
   if (OtherBits)

clang/test/CodeGen/arm-mve-intrinsics/vmovl.c

+// NOTE: Assertions have been autogenerated by utils/update_cc_test_checks.py
+// RUN: %clang_cc1 -triple thumbv8.1m.main-arm-none-eabi -target-feature +mve -mfloat-abi hard -fallow-half-arguments-and-returns -O0 -disable-O0-optnone -S -emit-llvm -o - %s | opt -S -mem2reg | FileCheck %s
+// RUN: %clang_cc1 -triple thumbv8.1m.main-arm-none-eabi -target-feature +mve -mfloat-abi hard -fallow-half-arguments-and-returns -O0 -disable-O0-optnone -DPOLYMORPHIC -S -emit-llvm -o - %s | opt -S -mem2reg | FileCheck %s
+
+#include <arm_mve.h>
+
+// CHECK-LABEL: @test_vmovlbq_s8(
+// CHECK-NEXT:  entry:
+// CHECK-NEXT:    [[TMP0:%.*]] = shufflevector <16 x i8> [[A:%.*]], <16 x i8> undef, <8 x i32> <i32 0, i32 2, i32 4, i32 6, i32 8, i32 10, i32 12, i32 14>
+// CHECK-NEXT:    [[TMP1:%.*]] = sext <8 x i8> [[TMP0]] to <8 x i16>
+// CHECK-NEXT:    ret <8 x i16> [[TMP1]]
+//
+int16x8_t test_vmovlbq_s8(int8x16_t a)
+{
+#ifdef POLYMORPHIC
+    return vmovlbq(a);
+#else /* POLYMORPHIC */
+    return vmovlbq_s8(a);
+#endif /* POLYMORPHIC */
+}
+
+// CHECK-LABEL: @test_vmovlbq_s16(
+// CHECK-NEXT:  entry:
+// CHECK-NEXT:    [[TMP0:%.*]] = shufflevector <8 x i16> [[A:%.*]], <8 x i16> undef, <4 x i32> <i32 0, i32 2, i32 4, i32 6>
+// CHECK-NEXT:    [[TMP1:%.*]] = sext <4 x i16> [[TMP0]] to <4 x i32>
+// CHECK-NEXT:    ret <4 x i32> [[TMP1]]
+//
+int32x4_t test_vmovlbq_s16(int16x8_t a)
+{
+#ifdef POLYMORPHIC
+    return vmovlbq(a);
+#else /* POLYMORPHIC */
+    return vmovlbq_s16(a);
+#endif /* POLYMORPHIC */
+}
+
+// CHECK-LABEL: @test_vmovlbq_u8(
+// CHECK-NEXT:  entry:
+// CHECK-NEXT:    [[TMP0:%.*]] = shufflevector <16 x i8> [[A:%.*]], <16 x i8> undef, <8 x i32> <i32 0, i32 2, i32 4, i32 6, i32 8, i32 10, i32 12, i32 14>
+// CHECK-NEXT:    [[TMP1:%.*]] = zext <8 x i8> [[TMP0]] to <8 x i16>
+// CHECK-NEXT:    ret <8 x i16> [[TMP1]]
+//
+uint16x8_t test_vmovlbq_u8(uint8x16_t a)
+{
+#ifdef POLYMORPHIC
+    return vmovlbq(a);
+#else /* POLYMORPHIC */
+    return vmovlbq_u8(a);
+#endif /* POLYMORPHIC */
+}
+
+// CHECK-LABEL: @test_vmovlbq_u16(
+// CHECK-NEXT:  entry:
+// CHECK-NEXT:    [[TMP0:%.*]] = shufflevector <8 x i16> [[A:%.*]], <8 x i16> undef, <4 x i32> <i32 0, i32 2, i32 4, i32 6>
+// CHECK-NEXT:    [[TMP1:%.*]] = zext <4 x i16> [[TMP0]] to <4 x i32>
+// CHECK-NEXT:    ret <4 x i32> [[TMP1]]
+//
+uint32x4_t test_vmovlbq_u16(uint16x8_t a)
+{
+#ifdef POLYMORPHIC
+    return vmovlbq(a);
+#else /* POLYMORPHIC */
+    return vmovlbq_u16(a);
+#endif /* POLYMORPHIC */
+}
+
+// CHECK-LABEL: @test_vmovltq_s8(
+// CHECK-NEXT:  entry:
+// CHECK-NEXT:    [[TMP0:%.*]] = shufflevector <16 x i8> [[A:%.*]], <16 x i8> undef, <8 x i32> <i32 1, i32 3, i32 5, i32 7, i32 9, i32 11, i32 13, i32 15>
+// CHECK-NEXT:    [[TMP1:%.*]] = sext <8 x i8> [[TMP0]] to <8 x i16>
+// CHECK-NEXT:    ret <8 x i16> [[TMP1]]
+//
+int16x8_t test_vmovltq_s8(int8x16_t a)
+{
+#ifdef POLYMORPHIC
+    return vmovltq(a);
+#else /* POLYMORPHIC */
+    return vmovltq_s8(a);
+#endif /* POLYMORPHIC */
+}
+
+// CHECK-LABEL: @test_vmovltq_s16(
+// CHECK-NEXT:  entry:
+// CHECK-NEXT:    [[TMP0:%.*]] = shufflevector <8 x i16> [[A:%.*]], <8 x i16> undef, <4 x i32> <i32 1, i32 3, i32 5, i32 7>
+// CHECK-NEXT:    [[TMP1:%.*]] = sext <4 x i16> [[TMP0]] to <4 x i32>
+// CHECK-NEXT:    ret <4 x i32> [[TMP1]]
+//
+int32x4_t test_vmovltq_s16(int16x8_t a)
+{
+#ifdef POLYMORPHIC
+    return vmovltq(a);
+#else /* POLYMORPHIC */
+    return vmovltq_s16(a);
+#endif /* POLYMORPHIC */
+}
+
+// CHECK-LABEL: @test_vmovltq_u8(
+// CHECK-NEXT:  entry:
+// CHECK-NEXT:    [[TMP0:%.*]] = shufflevector <16 x i8> [[A:%.*]], <16 x i8> undef, <8 x i32> <i32 1, i32 3, i32 5, i32 7, i32 9, i32 11, i32 13, i32 15>
+// CHECK-NEXT:    [[TMP1:%.*]] = zext <8 x i8> [[TMP0]] to <8 x i16>
+// CHECK-NEXT:    ret <8 x i16> [[TMP1]]
+//
+uint16x8_t test_vmovltq_u8(uint8x16_t a)
+{
+#ifdef POLYMORPHIC
+    return vmovltq(a);
+#else /* POLYMORPHIC */
+    return vmovltq_u8(a);
+#endif /* POLYMORPHIC */
+}
+
+// CHECK-LABEL: @test_vmovltq_u16(
+// CHECK-NEXT:  entry:
+// CHECK-NEXT:    [[TMP0:%.*]] = shufflevector <8 x i16> [[A:%.*]], <8 x i16> undef, <4 x i32> <i32 1, i32 3, i32 5, i32 7>
+// CHECK-NEXT:    [[TMP1:%.*]] = zext <4 x i16> [[TMP0]] to <4 x i32>
+// CHECK-NEXT:    ret <4 x i32> [[TMP1]]
+//
+uint32x4_t test_vmovltq_u16(uint16x8_t a)
+{
+#ifdef POLYMORPHIC
+    return vmovltq(a);
+#else /* POLYMORPHIC */
+    return vmovltq_u16(a);
+#endif /* POLYMORPHIC */
+}
+

llvm/lib/Target/ARM/ARMInstrMVE.td

 let Predicates = [HasMVEInt] in {
   def : Pat<(sext_inreg (v4i32 MQPR:$src), v4i16),
             (MVE_VMOVLs16bh MQPR:$src)>;
   def : Pat<(sext_inreg (v8i16 MQPR:$src), v8i8),
             (MVE_VMOVLs8bh MQPR:$src)>;
   def : Pat<(sext_inreg (v4i32 MQPR:$src), v4i8),
             (MVE_VMOVLs16bh (MVE_VMOVLs8bh MQPR:$src))>;
 
+  let Predicates = [IsLE,HasMVEInt] in {
+    def : Pat<(sext_inreg (v8i16 (bitconvert (ARMvrev16 (v16i8 MQPR:$src)))),
+                          v8i8), (MVE_VMOVLs8th MQPR:$src)>;
+    def : Pat<(sext_inreg (v4i32 (bitconvert (ARMvrev32 (v8i16 MQPR:$src)))),
+                          v4i16), (MVE_VMOVLs16th MQPR:$src)>;
+    def : Pat<(ARMvbicImm (v8i16 (bitconvert (ARMvrev16 (v16i8 MQPR:$src)))),
+                          (i32 0xAFF)), (MVE_VMOVLu8th MQPR:$src)>;
+    def : Pat<(and (v4i32 (bitconvert (ARMvrev32 (v8i16 MQPR:$src)))),
+                   (v4i32 (ARMvmovImm (i32 0xCFF)))),
+                   (MVE_VMOVLs16th MQPR:$src)>;
+  }
+
   // zext_inreg 16 -> 32
   def : Pat<(and (v4i32 MQPR:$src), (v4i32 (ARMvmovImm (i32 0xCFF)))),
             (MVE_VMOVLu16bh MQPR:$src)>;
   // zext_inreg 8 -> 16
   def : Pat<(ARMvbicImm (v8i16 MQPR:$src), (i32 0xAFF)),
             (MVE_VMOVLu8bh MQPR:$src)>;
 }
 

llvm/test/CodeGen/Thumb2/mve-intrinsics/vmovl.ll

+; NOTE: Assertions have been autogenerated by utils/update_llc_test_checks.py
+; RUN: llc -mtriple=thumbv8.1m.main -mattr=+mve.fp -verify-machineinstrs -o - %s | FileCheck %s
+
+define arm_aapcs_vfpcc <8 x i16> @test_vmovlbq_s8(<16 x i8> %a) {
+; CHECK-LABEL: test_vmovlbq_s8:
+; CHECK:       @ %bb.0: @ %entry
+; CHECK-NEXT:    vmovlb.s8 q0, q0
+; CHECK-NEXT:    bx lr
+entry:
+  %0 = shufflevector <16 x i8> %a, <16 x i8> undef, <8 x i32> <i32 0, i32 2, i32 4, i32 6, i32 8, i32 10, i32 12, i32 14>
+  %1 = sext <8 x i8> %0 to <8 x i16>
+  ret <8 x i16> %1
+}
+
+define arm_aapcs_vfpcc <4 x i32> @test_vmovlbq_s16(<8 x i16> %a) {
+; CHECK-LABEL: test_vmovlbq_s16:
+; CHECK:       @ %bb.0: @ %entry
+; CHECK-NEXT:    vmovlb.s16 q0, q0
+; CHECK-NEXT:    bx lr
+entry:
+  %0 = shufflevector <8 x i16> %a, <8 x i16> undef, <4 x i32> <i32 0, i32 2, i32 4, i32 6>
+  %1 = sext <4 x i16> %0 to <4 x i32>
+  ret <4 x i32> %1
+}
+
+define arm_aapcs_vfpcc <8 x i16> @test_vmovlbq_u8(<16 x i8> %a) {
+; CHECK-LABEL: test_vmovlbq_u8:
+; CHECK:       @ %bb.0: @ %entry
+; CHECK-NEXT:    vmovlb.u8 q0, q0
+; CHECK-NEXT:    bx lr
+entry:
+  %0 = shufflevector <16 x i8> %a, <16 x i8> undef, <8 x i32> <i32 0, i32 2, i32 4, i32 6, i32 8, i32 10, i32 12, i32 14>
+  %1 = zext <8 x i8> %0 to <8 x i16>
+  ret <8 x i16> %1
+}
+
+define arm_aapcs_vfpcc <4 x i32> @test_vmovlbq_u16(<8 x i16> %a) {
+; CHECK-LABEL: test_vmovlbq_u16:
+; CHECK:       @ %bb.0: @ %entry
+; CHECK-NEXT:    vmovlb.u16 q0, q0
+; CHECK-NEXT:    bx lr
+entry:
+  %0 = shufflevector <8 x i16> %a, <8 x i16> undef, <4 x i32> <i32 0, i32 2, i32 4, i32 6>
+  %1 = zext <4 x i16> %0 to <4 x i32>
+  ret <4 x i32> %1
+}
+
+define arm_aapcs_vfpcc <8 x i16> @test_vmovltq_s8(<16 x i8> %a) {
+; CHECK-LABEL: test_vmovltq_s8:
+; CHECK:       @ %bb.0: @ %entry
+; CHECK-NEXT:    vmovlt.s8 q0, q0
+; CHECK-NEXT:    bx lr
+entry:
+  %0 = shufflevector <16 x i8> %a, <16 x i8> undef, <8 x i32> <i32 1, i32 3, i32 5, i32 7, i32 9, i32 11, i32 13, i32 15>
+  %1 = sext <8 x i8> %0 to <8 x i16>
+  ret <8 x i16> %1
+}
+
+define arm_aapcs_vfpcc <4 x i32> @test_vmovltq_s16(<8 x i16> %a) {
+; CHECK-LABEL: test_vmovltq_s16:
+; CHECK:       @ %bb.0: @ %entry
+; CHECK-NEXT:    vmovlt.s16 q0, q0
+; CHECK-NEXT:    bx lr
+entry:
+  %0 = shufflevector <8 x i16> %a, <8 x i16> undef, <4 x i32> <i32 1, i32 3, i32 5, i32 7>
+  %1 = sext <4 x i16> %0 to <4 x i32>
+  ret <4 x i32> %1
+}
+
+define arm_aapcs_vfpcc <8 x i16> @test_vmovltq_u8(<16 x i8> %a) {
+; CHECK-LABEL: test_vmovltq_u8:
+; CHECK:       @ %bb.0: @ %entry
+; CHECK-NEXT:    vmovlt.u8 q0, q0
+; CHECK-NEXT:    bx lr
+entry:
+  %0 = shufflevector <16 x i8> %a, <16 x i8> undef, <8 x i32> <i32 1, i32 3, i32 5, i32 7, i32 9, i32 11, i32 13, i32 15>
+  %1 = zext <8 x i8> %0 to <8 x i16>
+  ret <8 x i16> %1
+}
+
+define arm_aapcs_vfpcc <4 x i32> @test_vmovltq_u16(<8 x i16> %a) {
+; CHECK-LABEL: test_vmovltq_u16:
+; CHECK:       @ %bb.0: @ %entry
+; CHECK-NEXT:    vmovlt.s16 q0, q0
+; CHECK-NEXT:    bx lr
+entry:
+  %0 = shufflevector <8 x i16> %a, <8 x i16> undef, <4 x i32> <i32 1, i32 3, i32 5, i32 7>
+  %1 = zext <4 x i16> %0 to <4 x i32>
+  ret <4 x i32> %1
+}

llvm/test/CodeGen/Thumb2/mve-shuffleext.ll

entry:
   %strided.vec = shufflevector <8 x i16> %src, <8 x i16> undef, <4 x i32> <i32 0, i32 2, i32 4, i32 6>
   %out = sext <4 x i16> %strided.vec to <4 x i32>
   ret <4 x i32> %out
 }
 
 define arm_aapcs_vfpcc <4 x i32> @sext_1357(<8 x i16> %src) {
 ; CHECK-LABEL: sext_1357:
 ; CHECK:       @ %bb.0: @ %entry
-; CHECK-NEXT:    vrev32.16 q0, q0
-; CHECK-NEXT:    vmovlb.s16 q0, q0
+; CHECK-NEXT:    vmovlt.s16 q0, q0
 ; CHECK-NEXT:    bx lr
 entry:
   %strided.vec = shufflevector <8 x i16> %src, <8 x i16> undef, <4 x i32> <i32 1, i32 3, i32 5, i32 7>
   %out = sext <4 x i16> %strided.vec to <4 x i32>
   ret <4 x i32> %out
 }
 
 define arm_aapcs_vfpcc <4 x i32> @zext_0246(<8 x i16> %src) {
 ; CHECK-LABEL: zext_0246:
 ; CHECK:       @ %bb.0: @ %entry
 ; CHECK-NEXT:    vmovlb.u16 q0, q0
 ; CHECK-NEXT:    bx lr
 entry:
   %strided.vec = shufflevector <8 x i16> %src, <8 x i16> undef, <4 x i32> <i32 0, i32 2, i32 4, i32 6>
   %out = zext <4 x i16> %strided.vec to <4 x i32>
   ret <4 x i32> %out
 }
 
 define arm_aapcs_vfpcc <4 x i32> @zext_1357(<8 x i16> %src) {
 ; CHECK-LABEL: zext_1357:
 ; CHECK:       @ %bb.0: @ %entry
-; CHECK-NEXT:    vrev32.16 q0, q0
-; CHECK-NEXT:    vmovlb.u16 q0, q0
+; CHECK-NEXT:    vmovlt.s16 q0, q0
 ; CHECK-NEXT:    bx lr
 entry:
   %strided.vec = shufflevector <8 x i16> %src, <8 x i16> undef, <4 x i32> <i32 1, i32 3, i32 5, i32 7>
   %out = zext <4 x i16> %strided.vec to <4 x i32>
   ret <4 x i32> %out
 }
 
 define arm_aapcs_vfpcc <8 x i16> @sext_02468101214(<16 x i8> %src) {
 ; CHECK-LABEL: sext_02468101214:
 ; CHECK:       @ %bb.0: @ %entry
 ; CHECK-NEXT:    vmovlb.s8 q0, q0
 ; CHECK-NEXT:    bx lr
 entry:
   %strided.vec = shufflevector <16 x i8> %src, <16 x i8> undef, <8 x i32> <i32 0, i32 2, i32 4, i32 6, i32 8, i32 10, i32 12, i32 14>
   %out = sext <8 x i8> %strided.vec to <8 x i16>
   ret <8 x i16> %out
 }
 
 define arm_aapcs_vfpcc <8 x i16> @sext_13579111315(<16 x i8> %src) {
 ; CHECK-LABEL: sext_13579111315:
 ; CHECK:       @ %bb.0: @ %entry
-; CHECK-NEXT:    vrev16.8 q0, q0
-; CHECK-NEXT:    vmovlb.s8 q0, q0
+; CHECK-NEXT:    vmovlt.s8 q0, q0
 ; CHECK-NEXT:    bx lr
 entry:
   %strided.vec = shufflevector <16 x i8> %src, <16 x i8> undef, <8 x i32> <i32 1, i32 3, i32 5, i32 7, i32 9, i32 11, i32 13, i32 15>
   %out = sext <8 x i8> %strided.vec to <8 x i16>
   ret <8 x i16> %out
 }
 
 define arm_aapcs_vfpcc <8 x i16> @zext_02468101214(<16 x i8> %src) {
 ; CHECK-LABEL: zext_02468101214:
 ; CHECK:       @ %bb.0: @ %entry
 ; CHECK-NEXT:    vmovlb.u8 q0, q0
 ; CHECK-NEXT:    bx lr
 entry:
   %strided.vec = shufflevector <16 x i8> %src, <16 x i8> undef, <8 x i32> <i32 0, i32 2, i32 4, i32 6, i32 8, i32 10, i32 12, i32 14>
   %out = zext <8 x i8> %strided.vec to <8 x i16>
   ret <8 x i16> %out
 }
 
 define arm_aapcs_vfpcc <8 x i16> @zext_13579111315(<16 x i8> %src) {
 ; CHECK-LABEL: zext_13579111315:
 ; CHECK:       @ %bb.0: @ %entry
-; CHECK-NEXT:    vrev16.8 q0, q0
-; CHECK-NEXT:    vmovlb.u8 q0, q0
+; CHECK-NEXT:    vmovlt.u8 q0, q0
 ; CHECK-NEXT:    bx lr
 entry:
   %strided.vec = shufflevector <16 x i8> %src, <16 x i8> undef, <8 x i32> <i32 1, i32 3, i32 5, i32 7, i32 9, i32 11, i32 13, i32 15>
   %out = zext <8 x i8> %strided.vec to <8 x i16>
   ret <8 x i16> %out
 }