[AArch64 NEON] Fix a pattern match failure with NEON_VDUP.

This failure caused by improper condition when lowering shuffle_vector
to scalar_to_vector. After this patch NEON_VDUP with v1i64 will not
be generated.

llvm-svn: 197966

llvm/lib/Target/AArch64/AArch64ISelLowering.cpp

@@ -4070,9 +4070,7 @@ AArch64TargetLowering::LowerBUILD_VECTOR(SDValue Op, SelectionDAG &DAG,
   if (ValueCounts.size() == 0)
     return DAG.getUNDEF(VT);
 
-  // Loads are better lowered with insert_vector_elt.
+  if (isOnlyLowElement)
-  // Keep going if we are hitting this case.
-  if (isOnlyLowElement && !ISD::isNormalLoad(Value.getNode()))
     return DAG.getNode(ISD::SCALAR_TO_VECTOR, DL, VT, Value);
 
   unsigned EltSize = VT.getVectorElementType().getSizeInBits();

llvm/lib/Target/AArch64/AArch64InstrNEON.td

@@ -3690,12 +3690,16 @@ def : LD1R_pattern<v2f32, f32, load, LD1R_2S>;
 def : LD1R_pattern<v4i32, i32, load, LD1R_4S>;
 def : LD1R_pattern<v4f32, f32, load, LD1R_4S>;
 
-def : LD1R_pattern<v1i64, i64, load, LD1R_1D>;
-def : LD1R_pattern<v1f64, f64, load, LD1R_1D>;
-
 def : LD1R_pattern<v2i64, i64, load, LD1R_2D>;
 def : LD1R_pattern<v2f64, f64, load, LD1R_2D>;
 
+class LD1R_pattern_v1 <ValueType VTy, ValueType DTy, PatFrag LoadOp,
+                       Instruction INST>
+  : Pat<(VTy (scalar_to_vector (DTy (LoadOp GPR64xsp:$Rn)))),
+        (VTy (INST GPR64xsp:$Rn))>;
+
+def : LD1R_pattern_v1<v1i64, i64, load, LD1R_1D>;
+def : LD1R_pattern_v1<v1f64, f64, load, LD1R_1D>;
 
 multiclass VectorList_Bare_BHSD<string PREFIX, int Count,
                                 RegisterClass RegList> {

llvm/test/CodeGen/AArch64/neon-simd-ldst-one.ll

@@ -236,6 +236,31 @@ entry:
   ret <1 x double> %1
 }
 
+define <1 x i64> @testDUP.v1i64(i64* %a, i64* %b) #0 {
+; As there is a store operation depending on %1, LD1R pattern can't be selected.
+; So LDR and FMOV should be emitted.
+; CHECK-LABEL: testDUP.v1i64
+; CHECK: ldr {{x[0-9]+}}, [{{x[0-9]+}}]
+; CHECK: fmov {{d[0-9]+}}, {{x[0-9]+}}
+; CHECK: str {{x[0-9]+}}, [{{x[0-9]+}}]
+  %1 = load i64* %a, align 8
+  store i64 %1, i64* %b, align 8
+  %vecinit.i = insertelement <1 x i64> undef, i64 %1, i32 0
+  ret <1 x i64> %vecinit.i
+}
+
+define <1 x double> @testDUP.v1f64(double* %a, double* %b) #0 {
+; As there is a store operation depending on %1, LD1R pattern can't be selected.
+; So LDR and FMOV should be emitted.
+; CHECK-LABEL: testDUP.v1f64
+; CHECK: ldr {{d[0-9]+}}, [{{x[0-9]+}}]
+; CHECK: str {{d[0-9]+}}, [{{x[0-9]+}}]
+  %1 = load double* %a, align 8
+  store double %1, double* %b, align 8
+  %vecinit.i = insertelement <1 x double> undef, double %1, i32 0
+  ret <1 x double> %vecinit.i
+}
+
 define %struct.int8x16x2_t @test_vld2q_dup_s8(i8* %a) {
 ; CHECK-LABEL: test_vld2q_dup_s8
 ; CHECK: ld2r {{{v[0-9]+}}.16b, {{v[0-9]+}}.16b}, [x0]