The Neon VCVT (between floating-point and fixed-point, Advanced SIMD)

instructions can be used to match combinations of multiply/divide and VCVT 
(between floating-point and integer, Advanced SIMD).  Basically the VCVT 
immediate operand that specifies the number of fraction bits corresponds to a 
floating-point multiply or divide by the corresponding power of 2.

For example, VCVT (floating-point to fixed-point, Advanced SIMD) can replace a 
combination of VMUL and VCVT (floating-point to integer) as follows:

Example (assume d17 = <float 8.000000e+00, float 8.000000e+00>):
  vmul.f32        d16, d17, d16
  vcvt.s32.f32    d16, d16
becomes:
  vcvt.s32.f32    d16, d16, #3

Similarly, VCVT (fixed-point to floating-point, Advanced SIMD) can replace a 
combinations of VCVT (integer to floating-point) and VDIV as follows:

Example (assume d17 = <float 8.000000e+00, float 8.000000e+00>):
  vcvt.f32.s32    d16, d16
  vdiv.f32        d16, d17, d16
becomes:
  vcvt.f32.s32    d16, d16, #3

llvm-svn: 133813
This commit is contained in:
Chad Rosier 2011-06-24 19:23:04 +00:00
parent 1be944a466
commit fa8d89327f
3 changed files with 305 additions and 1 deletions

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@ -506,6 +506,9 @@ ARMTargetLowering::ARMTargetLowering(TargetMachine &TM)
setTargetDAGCombine(ISD::VECTOR_SHUFFLE);
setTargetDAGCombine(ISD::INSERT_VECTOR_ELT);
setTargetDAGCombine(ISD::STORE);
setTargetDAGCombine(ISD::FP_TO_SINT);
setTargetDAGCombine(ISD::FP_TO_UINT);
setTargetDAGCombine(ISD::FDIV);
}
computeRegisterProperties();
@ -6479,7 +6482,104 @@ static SDValue PerformVDUPLANECombine(SDNode *N,
return DCI.DAG.getNode(ISD::BITCAST, N->getDebugLoc(), VT, Op);
}
/// getVShiftImm - Check if this is a valid build_vector for the immediate
// isConstVecPow2 - Return true if each vector element is a power of 2, all
// elements are the same constant, C, and Log2(C) ranges from 1 to 32.
static bool isConstVecPow2(SDValue ConstVec, bool isSigned, uint64_t &C)
{
integerPart c0, cN;
for (unsigned I = 0, E = ConstVec.getValueType().getVectorNumElements();
I != E; I++) {
ConstantFPSDNode *C = dyn_cast<ConstantFPSDNode>(ConstVec.getOperand(I));
if (!C)
return false;
bool isExact;
APFloat APF = C->getValueAPF();
if (APF.convertToInteger(&cN, 64, isSigned, APFloat::rmTowardZero, &isExact)
!= APFloat::opOK || !isExact)
return false;
c0 = (I == 0) ? cN : c0;
if (!isPowerOf2_64(cN) || c0 != cN || Log2_64(c0) < 1 || Log2_64(c0) > 32)
return false;
}
C = c0;
return true;
}
/// PerformVCVTCombine - VCVT (floating-point to fixed-point, Advanced SIMD)
/// can replace combinations of VMUL and VCVT (floating-point to integer)
/// when the VMUL has a constant operand that is a power of 2.
///
/// Example (assume d17 = <float 8.000000e+00, float 8.000000e+00>):
/// vmul.f32 d16, d17, d16
/// vcvt.s32.f32 d16, d16
/// becomes:
/// vcvt.s32.f32 d16, d16, #3
static SDValue PerformVCVTCombine(SDNode *N,
TargetLowering::DAGCombinerInfo &DCI,
const ARMSubtarget *Subtarget) {
SelectionDAG &DAG = DCI.DAG;
SDValue Op = N->getOperand(0);
if (!Subtarget->hasNEON() || !Op.getValueType().isVector() ||
Op.getOpcode() != ISD::FMUL)
return SDValue();
uint64_t C;
SDValue N0 = Op->getOperand(0);
SDValue ConstVec = Op->getOperand(1);
bool isSigned = N->getOpcode() == ISD::FP_TO_SINT;
if (ConstVec.getOpcode() != ISD::BUILD_VECTOR ||
!isConstVecPow2(ConstVec, isSigned, C))
return SDValue();
unsigned IntrinsicOpcode = isSigned ? Intrinsic::arm_neon_vcvtfp2fxs :
Intrinsic::arm_neon_vcvtfp2fxu;
return DAG.getNode(ISD::INTRINSIC_WO_CHAIN, N->getDebugLoc(),
N->getValueType(0),
DAG.getConstant(IntrinsicOpcode, MVT::i32), N0,
DAG.getConstant(Log2_64(C), MVT::i32));
}
/// PerformVDIVCombine - VCVT (fixed-point to floating-point, Advanced SIMD)
/// can replace combinations of VCVT (integer to floating-point) and VDIV
/// when the VDIV has a constant operand that is a power of 2.
///
/// Example (assume d17 = <float 8.000000e+00, float 8.000000e+00>):
/// vcvt.f32.s32 d16, d16
/// vdiv.f32 d16, d17, d16
/// becomes:
/// vcvt.f32.s32 d16, d16, #3
static SDValue PerformVDIVCombine(SDNode *N,
TargetLowering::DAGCombinerInfo &DCI,
const ARMSubtarget *Subtarget) {
SelectionDAG &DAG = DCI.DAG;
SDValue Op = N->getOperand(0);
unsigned OpOpcode = Op.getNode()->getOpcode();
if (!Subtarget->hasNEON() || !N->getValueType(0).isVector() ||
(OpOpcode != ISD::SINT_TO_FP && OpOpcode != ISD::UINT_TO_FP))
return SDValue();
uint64_t C;
SDValue ConstVec = N->getOperand(1);
bool isSigned = OpOpcode == ISD::SINT_TO_FP;
if (ConstVec.getOpcode() != ISD::BUILD_VECTOR ||
!isConstVecPow2(ConstVec, isSigned, C))
return SDValue();
unsigned IntrinsicOpcode = isSigned ? Intrinsic::arm_neon_vcvtfxs2fp :
Intrinsic::arm_neon_vcvtfxu2fp;
return DAG.getNode(ISD::INTRINSIC_WO_CHAIN, N->getDebugLoc(),
Op.getValueType(),
DAG.getConstant(IntrinsicOpcode, MVT::i32),
Op.getOperand(0), DAG.getConstant(Log2_64(C), MVT::i32));
}
/// Getvshiftimm - Check if this is a valid build_vector for the immediate
/// operand of a vector shift operation, where all the elements of the
/// build_vector must have the same constant integer value.
static bool getVShiftImm(SDValue Op, unsigned ElementBits, int64_t &Cnt) {
@ -6868,6 +6968,9 @@ SDValue ARMTargetLowering::PerformDAGCombine(SDNode *N,
case ISD::INSERT_VECTOR_ELT: return PerformInsertEltCombine(N, DCI);
case ISD::VECTOR_SHUFFLE: return PerformVECTOR_SHUFFLECombine(N, DCI.DAG);
case ARMISD::VDUPLANE: return PerformVDUPLANECombine(N, DCI);
case ISD::FP_TO_SINT:
case ISD::FP_TO_UINT: return PerformVCVTCombine(N, DCI, Subtarget);
case ISD::FDIV: return PerformVDIVCombine(N, DCI, Subtarget);
case ISD::INTRINSIC_WO_CHAIN: return PerformIntrinsicCombine(N, DCI.DAG);
case ISD::SHL:
case ISD::SRA:

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@ -0,0 +1,99 @@
; RUN: llc < %s -mtriple=armv7-apple-ios | FileCheck %s
@in = global float 0x400921FA00000000, align 4
; Test signed conversion.
; CHECK: t0
; CHECK-NOT: vmul
define void @t0() nounwind {
entry:
%tmp = load float* @in, align 4, !tbaa !0
%vecinit.i = insertelement <2 x float> undef, float %tmp, i32 0
%vecinit2.i = insertelement <2 x float> %vecinit.i, float %tmp, i32 1
%mul.i = fmul <2 x float> %vecinit2.i, <float 8.000000e+00, float 8.000000e+00>
%vcvt.i = fptosi <2 x float> %mul.i to <2 x i32>
tail call void @foo_int32x2_t(<2 x i32> %vcvt.i) nounwind
ret void
}
declare void @foo_int32x2_t(<2 x i32>)
; Test unsigned conversion.
; CHECK: t1
; CHECK-NOT: vmul
define void @t1() nounwind {
entry:
%tmp = load float* @in, align 4, !tbaa !0
%vecinit.i = insertelement <2 x float> undef, float %tmp, i32 0
%vecinit2.i = insertelement <2 x float> %vecinit.i, float %tmp, i32 1
%mul.i = fmul <2 x float> %vecinit2.i, <float 8.000000e+00, float 8.000000e+00>
%vcvt.i = fptoui <2 x float> %mul.i to <2 x i32>
tail call void @foo_uint32x2_t(<2 x i32> %vcvt.i) nounwind
ret void
}
declare void @foo_uint32x2_t(<2 x i32>)
; Test which should not fold due to non-power of 2.
; CHECK: t2
; CHECK: vmul
define void @t2() nounwind {
entry:
%tmp = load float* @in, align 4, !tbaa !0
%vecinit.i = insertelement <2 x float> undef, float %tmp, i32 0
%vecinit2.i = insertelement <2 x float> %vecinit.i, float %tmp, i32 1
%mul.i = fmul <2 x float> %vecinit2.i, <float 0x401B333340000000, float 0x401B333340000000>
%vcvt.i = fptosi <2 x float> %mul.i to <2 x i32>
tail call void @foo_int32x2_t(<2 x i32> %vcvt.i) nounwind
ret void
}
; Test which should not fold due to power of 2 out of range.
; CHECK: t3
; CHECK: vmul
define void @t3() nounwind {
entry:
%tmp = load float* @in, align 4, !tbaa !0
%vecinit.i = insertelement <2 x float> undef, float %tmp, i32 0
%vecinit2.i = insertelement <2 x float> %vecinit.i, float %tmp, i32 1
%mul.i = fmul <2 x float> %vecinit2.i, <float 0x4200000000000000, float 0x4200000000000000>
%vcvt.i = fptosi <2 x float> %mul.i to <2 x i32>
tail call void @foo_int32x2_t(<2 x i32> %vcvt.i) nounwind
ret void
}
; Test which case where const is max power of 2 (i.e., 2^32).
; CHECK: t4
; CHECK-NOT: vmul
define void @t4() nounwind {
entry:
%tmp = load float* @in, align 4, !tbaa !0
%vecinit.i = insertelement <2 x float> undef, float %tmp, i32 0
%vecinit2.i = insertelement <2 x float> %vecinit.i, float %tmp, i32 1
%mul.i = fmul <2 x float> %vecinit2.i, <float 0x41F0000000000000, float 0x41F0000000000000>
%vcvt.i = fptosi <2 x float> %mul.i to <2 x i32>
tail call void @foo_int32x2_t(<2 x i32> %vcvt.i) nounwind
ret void
}
; Test quadword.
; CHECK: t5
; CHECK-NOT: vmul
define void @t5() nounwind {
entry:
%tmp = load float* @in, align 4, !tbaa !0
%vecinit.i = insertelement <4 x float> undef, float %tmp, i32 0
%vecinit2.i = insertelement <4 x float> %vecinit.i, float %tmp, i32 1
%vecinit4.i = insertelement <4 x float> %vecinit2.i, float %tmp, i32 2
%vecinit6.i = insertelement <4 x float> %vecinit4.i, float %tmp, i32 3
%mul.i = fmul <4 x float> %vecinit6.i, <float 8.000000e+00, float 8.000000e+00, float 8.000000e+00, float 8.000000e+00>
%vcvt.i = fptosi <4 x float> %mul.i to <4 x i32>
tail call void @foo_int32x4_t(<4 x i32> %vcvt.i) nounwind
ret void
}
declare void @foo_int32x4_t(<4 x i32>)
!0 = metadata !{metadata !"float", metadata !1}
!1 = metadata !{metadata !"omnipotent char", metadata !2}
!2 = metadata !{metadata !"Simple C/C++ TBAA", null}

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@ -0,0 +1,102 @@
; RUN: llc < %s -mtriple=armv7-apple-ios | FileCheck %s
@in = global float 0x400921FA00000000, align 4
@iin = global i32 -1023, align 4
@uin = global i32 1023, align 4
declare void @foo_int32x4_t(<4 x i32>)
; Test signed conversion.
; CHECK: t1
; CHECK-NOT: vdiv
define void @t1() nounwind {
entry:
%tmp = load i32* @iin, align 4, !tbaa !3
%vecinit.i = insertelement <2 x i32> undef, i32 %tmp, i32 0
%vecinit2.i = insertelement <2 x i32> %vecinit.i, i32 %tmp, i32 1
%vcvt.i = sitofp <2 x i32> %vecinit2.i to <2 x float>
%div.i = fdiv <2 x float> %vcvt.i, <float 8.000000e+00, float 8.000000e+00>
tail call void @foo_float32x2_t(<2 x float> %div.i) nounwind
ret void
}
declare void @foo_float32x2_t(<2 x float>)
; Test unsigned conversion.
; CHECK: t2
; CHECK-NOT: vdiv
define void @t2() nounwind {
entry:
%tmp = load i32* @uin, align 4, !tbaa !3
%vecinit.i = insertelement <2 x i32> undef, i32 %tmp, i32 0
%vecinit2.i = insertelement <2 x i32> %vecinit.i, i32 %tmp, i32 1
%vcvt.i = uitofp <2 x i32> %vecinit2.i to <2 x float>
%div.i = fdiv <2 x float> %vcvt.i, <float 8.000000e+00, float 8.000000e+00>
tail call void @foo_float32x2_t(<2 x float> %div.i) nounwind
ret void
}
; Test which should not fold due to non-power of 2.
; CHECK: t3
; CHECK: vdiv
define void @t3() nounwind {
entry:
%tmp = load i32* @iin, align 4, !tbaa !3
%vecinit.i = insertelement <2 x i32> undef, i32 %tmp, i32 0
%vecinit2.i = insertelement <2 x i32> %vecinit.i, i32 %tmp, i32 1
%vcvt.i = sitofp <2 x i32> %vecinit2.i to <2 x float>
%div.i = fdiv <2 x float> %vcvt.i, <float 0x401B333340000000, float 0x401B333340000000>
tail call void @foo_float32x2_t(<2 x float> %div.i) nounwind
ret void
}
; Test which should not fold due to power of 2 out of range.
; CHECK: t4
; CHECK: vdiv
define void @t4() nounwind {
entry:
%tmp = load i32* @iin, align 4, !tbaa !3
%vecinit.i = insertelement <2 x i32> undef, i32 %tmp, i32 0
%vecinit2.i = insertelement <2 x i32> %vecinit.i, i32 %tmp, i32 1
%vcvt.i = sitofp <2 x i32> %vecinit2.i to <2 x float>
%div.i = fdiv <2 x float> %vcvt.i, <float 0x4200000000000000, float 0x4200000000000000>
tail call void @foo_float32x2_t(<2 x float> %div.i) nounwind
ret void
}
; Test case where const is max power of 2 (i.e., 2^32).
; CHECK: t5
; CHECK-NOT: vdiv
define void @t5() nounwind {
entry:
%tmp = load i32* @iin, align 4, !tbaa !3
%vecinit.i = insertelement <2 x i32> undef, i32 %tmp, i32 0
%vecinit2.i = insertelement <2 x i32> %vecinit.i, i32 %tmp, i32 1
%vcvt.i = sitofp <2 x i32> %vecinit2.i to <2 x float>
%div.i = fdiv <2 x float> %vcvt.i, <float 0x41F0000000000000, float 0x41F0000000000000>
tail call void @foo_float32x2_t(<2 x float> %div.i) nounwind
ret void
}
; Test quadword.
; CHECK: t6
; CHECK-NOT: vdiv
define void @t6() nounwind {
entry:
%tmp = load i32* @iin, align 4, !tbaa !3
%vecinit.i = insertelement <4 x i32> undef, i32 %tmp, i32 0
%vecinit2.i = insertelement <4 x i32> %vecinit.i, i32 %tmp, i32 1
%vecinit4.i = insertelement <4 x i32> %vecinit2.i, i32 %tmp, i32 2
%vecinit6.i = insertelement <4 x i32> %vecinit4.i, i32 %tmp, i32 3
%vcvt.i = sitofp <4 x i32> %vecinit6.i to <4 x float>
%div.i = fdiv <4 x float> %vcvt.i, <float 8.000000e+00, float 8.000000e+00, float 8.000000e+00, float 8.000000e+00>
tail call void @foo_float32x4_t(<4 x float> %div.i) nounwind
ret void
}
declare void @foo_float32x4_t(<4 x float>)
!0 = metadata !{metadata !"float", metadata !1}
!1 = metadata !{metadata !"omnipotent char", metadata !2}
!2 = metadata !{metadata !"Simple C/C++ TBAA", null}
!3 = metadata !{metadata !"int", metadata !1}