OSchip
/
llvm-project
mirror of https://github.com/THU-DSP-LAB/llvm-project.git
13
0
Fork 6
Code Issues Packages Projects Releases Wiki Activity

[AArch64] generate vuzp instead of mov 

when a BUILD_VECTOR is created out of a sequence of EXTRACT_VECTOR_ELT with a
specific pattern sequence, either <0, 2, 4, ...> or <1, 3, 5, ...>, replace the
BUILD_VECTOR with either vuzp1 or vuzp2.

With this patch LLVM generates the following code for the first function fun1 in the testcase:
adrp x8, .LCPI0_0
ldr  q0, [x8, :lo12:.LCPI0_0]
tbl  v0.16b, { v0.16b }, v0.16b
ext  v1.16b, v0.16b, v0.16b, #8
uzp1 v0.8b, v0.8b, v1.8b
str  d0, [x8]
ret

Without this patch LLVM currently generates this code:
adrp    x8, .LCPI0_0
ldr     q0, [x8, :lo12:.LCPI0_0]
tbl     v0.16b, { v0.16b }, v0.16b
mov     v1.16b, v0.16b
mov     v1.b[1], v0.b[2]
mov     v1.b[2], v0.b[4]
mov     v1.b[3], v0.b[6]
mov     v1.b[4], v0.b[8]
mov     v1.b[5], v0.b[10]
mov     v1.b[6], v0.b[12]
mov     v1.b[7], v0.b[14]
str     d1, [x8]
ret

llvm-svn: 326443
This commit is contained in:
Sebastian Pop 2018-03-01 15:47:39 +00:00
parent 3fd43a843b
commit c33af715d7
2 changed files with 110 additions and 0 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

59
llvm/lib/Target/AArch64/AArch64ISelLowering.cpp
View File

@ -6706,16 +6706,20 @@ SDValue AArch64TargetLowering::LowerBUILD_VECTOR(SDValue Op,
// select the values we'll be overwriting for the non-constant
// lanes such that we can directly materialize the vector
// some other way (MOVI, e.g.), we can be sneaky.
// 5) if all operands are EXTRACT_VECTOR_ELT, check for VUZP.
unsigned NumElts = VT.getVectorNumElements();
bool isOnlyLowElement = true;
bool usesOnlyOneValue = true;
bool usesOnlyOneConstantValue = true;
bool isConstant = true;
bool AllLanesExtractElt = true;
unsigned NumConstantLanes = 0;
SDValue Value;
SDValue ConstantValue;
for (unsigned i = 0; i < NumElts; ++i) {
SDValue V = Op.getOperand(i);
if (V.getOpcode() != ISD::EXTRACT_VECTOR_ELT)
AllLanesExtractElt = false;
if (V.isUndef())
continue;
if (i > 0)
@ -6748,6 +6752,61 @@ SDValue AArch64TargetLowering::LowerBUILD_VECTOR(SDValue Op,
return DAG.getNode(ISD::SCALAR_TO_VECTOR, dl, VT, Value);
}
if (AllLanesExtractElt) {
SDNode *Vector = nullptr;
bool Even = false;
bool Odd = false;
// Check whether the extract elements match the Even pattern <0,2,4,...> or
// the Odd pattern <1,3,5,...>.
for (unsigned i = 0; i < NumElts; ++i) {
SDValue V = Op.getOperand(i);
const SDNode *N = V.getNode();
if (!isa<ConstantSDNode>(N->getOperand(1)))
break;
// All elements are extracted from the same vector.
if (!Vector)
Vector = N->getOperand(0).getNode();
else if (Vector != N->getOperand(0).getNode()) {
Odd = false;
Even = false;
break;
}
// Extracted values are either at Even indices <0,2,4,...> or at Odd
// indices <1,3,5,...>.
uint64_t Val = N->getConstantOperandVal(1);
if (Val == 2 * i) {
Even = true;
continue;
}
if (Val - 1 == 2 * i) {
Odd = true;
continue;
}
// Something does not match: abort.
Odd = false;
Even = false;
break;
}
if (Even || Odd) {
SDValue LHS =
DAG.getNode(ISD::EXTRACT_SUBVECTOR, dl, VT, SDValue(Vector, 0),
DAG.getConstant(0, dl, MVT::i64));
SDValue RHS =
DAG.getNode(ISD::EXTRACT_SUBVECTOR, dl, VT, SDValue(Vector, 0),
DAG.getConstant(NumElts, dl, MVT::i64));
if (Even && !Odd)
return DAG.getNode(AArch64ISD::UZP1, dl, DAG.getVTList(VT, VT), LHS,
RHS);
if (Odd && !Even)
return DAG.getNode(AArch64ISD::UZP2, dl, DAG.getVTList(VT, VT), LHS,
RHS);
}
}
// Use DUP for non-constant splats. For f32 constant splats, reduce to
// i32 and try again.
if (usesOnlyOneValue) {

51
llvm/test/CodeGen/AArch64/aarch64-vuzp.ll Normal file
View File

@ -0,0 +1,51 @@
; RUN: llc -mtriple=aarch64-none-linux-gnu -mattr=+neon < %s | FileCheck %s
; CHECK-LABEL: fun1:
; CHECK: uzp1 {{v[0-9]+}}.8b, {{v[0-9]+}}.8b, {{v[0-9]+}}.8b
; CHECK-NOT: mov
define i32 @fun1() {
entry:
%vtbl1.i.1 = tail call <16 x i8> @llvm.aarch64.neon.tbl1.v16i8(<16 x i8> <i8 0, i8 16, i8 19, i8 4, i8 -65, i8 -65, i8 -71, i8 -71, i8 0, i8 0, i8 0, i8 0, i8 0, i8 0, i8 0, i8 0>, <16 x i8> undef)
%vuzp.i212.1 = shufflevector <16 x i8> %vtbl1.i.1, <16 x i8> undef, <8 x i32> <i32 0, i32 2, i32 4, i32 6, i32 8, i32 10, i32 12, i32 14>
%scevgep = getelementptr <8 x i8>, <8 x i8>* undef, i64 1
store <8 x i8> %vuzp.i212.1, <8 x i8>* %scevgep, align 1
ret i32 undef
}
; CHECK-LABEL: fun2:
; CHECK: uzp2 {{v[0-9]+}}.8b, {{v[0-9]+}}.8b, {{v[0-9]+}}.8b
; CHECK-NOT: mov
define i32 @fun2() {
entry:
%vtbl1.i.1 = tail call <16 x i8> @llvm.aarch64.neon.tbl1.v16i8(<16 x i8> <i8 0, i8 16, i8 19, i8 4, i8 -65, i8 -65, i8 -71, i8 -71, i8 0, i8 0, i8 0, i8 0, i8 0, i8 0, i8 0, i8 0>, <16 x i8> undef)
%vuzp.i212.1 = shufflevector <16 x i8> %vtbl1.i.1, <16 x i8> undef, <8 x i32> <i32 1, i32 3, i32 5, i32 7, i32 9, i32 11, i32 13, i32 15>
%scevgep = getelementptr <8 x i8>, <8 x i8>* undef, i64 1
store <8 x i8> %vuzp.i212.1, <8 x i8>* %scevgep, align 1
ret i32 undef
}
; CHECK-LABEL: fun3:
; CHECK-NOT: uzp1
; CHECK: mov
define i32 @fun3() {
entry:
%vtbl1.i.1 = tail call <16 x i8> @llvm.aarch64.neon.tbl1.v16i8(<16 x i8> <i8 0, i8 16, i8 19, i8 4, i8 -65, i8 -65, i8 -71, i8 -71, i8 0, i8 0, i8 0, i8 0, i8 0, i8 0, i8 0, i8 0>, <16 x i8> undef)
%vuzp.i212.1 = shufflevector <16 x i8> %vtbl1.i.1, <16 x i8> undef, <8 x i32> <i32 0, i32 2, i32 4, i32 6, i32 8, i32 10, i32 12, i32 15>
%scevgep = getelementptr <8 x i8>, <8 x i8>* undef, i64 1
store <8 x i8> %vuzp.i212.1, <8 x i8>* %scevgep, align 1
ret i32 undef
}
; CHECK-LABEL: fun4:
; CHECK-NOT: uzp2
; CHECK: mov
define i32 @fun4() {
entry:
%vtbl1.i.1 = tail call <16 x i8> @llvm.aarch64.neon.tbl1.v16i8(<16 x i8> <i8 0, i8 16, i8 19, i8 4, i8 -65, i8 -65, i8 -71, i8 -71, i8 0, i8 0, i8 0, i8 0, i8 0, i8 0, i8 0, i8 0>, <16 x i8> undef)
%vuzp.i212.1 = shufflevector <16 x i8> %vtbl1.i.1, <16 x i8> undef, <8 x i32> <i32 3, i32 3, i32 5, i32 7, i32 9, i32 11, i32 13, i32 15>
%scevgep = getelementptr <8 x i8>, <8 x i8>* undef, i64 1
store <8 x i8> %vuzp.i212.1, <8 x i8>* %scevgep, align 1
ret i32 undef
}
declare <16 x i8> @llvm.aarch64.neon.tbl1.v16i8(<16 x i8>, <16 x i8>)