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Fix FCOPYSIGN expansion 

In expansion of FCOPYSIGN, the shift node is missing when the two
operands of FCOPYSIGN are of the same size. We should always generate
shift node (if the required shift bit is not zero) to put the sign
bit into the right position, regardless of the size of underlying
types.

Differential Revision: https://reviews.llvm.org/D49973

llvm-svn: 338665
This commit is contained in:
Lei Liu 2018-08-02 01:54:12 +00:00
parent 06baa7e0f2
commit b9a7b7a84d
2 changed files with 35 additions and 20 deletions
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30
llvm/lib/CodeGen/SelectionDAG/LegalizeDAG.cpp
View File

@ -1489,24 +1489,20 @@ SDValue SelectionDAGLegalize::ExpandFCOPYSIGN(SDNode *Node) const {
// Get the signbit at the right position for MagAsInt.
int ShiftAmount = SignAsInt.SignBit - MagAsInt.SignBit;
if (SignBit.getValueSizeInBits() > ClearedSign.getValueSizeInBits()) {
if (ShiftAmount > 0) {
SDValue ShiftCnst = DAG.getConstant(ShiftAmount, DL, IntVT);
SignBit = DAG.getNode(ISD::SRL, DL, IntVT, SignBit, ShiftCnst);
} else if (ShiftAmount < 0) {
SDValue ShiftCnst = DAG.getConstant(-ShiftAmount, DL, IntVT);
SignBit = DAG.getNode(ISD::SHL, DL, IntVT, SignBit, ShiftCnst);
}
SignBit = DAG.getNode(ISD::TRUNCATE, DL, MagVT, SignBit);
} else if (SignBit.getValueSizeInBits() < ClearedSign.getValueSizeInBits()) {
EVT ShiftVT = IntVT;
if (SignBit.getValueSizeInBits() < ClearedSign.getValueSizeInBits()) {
SignBit = DAG.getNode(ISD::ZERO_EXTEND, DL, MagVT, SignBit);
if (ShiftAmount > 0) {
SDValue ShiftCnst = DAG.getConstant(ShiftAmount, DL, MagVT);
SignBit = DAG.getNode(ISD::SRL, DL, MagVT, SignBit, ShiftCnst);
} else if (ShiftAmount < 0) {
SDValue ShiftCnst = DAG.getConstant(-ShiftAmount, DL, MagVT);
SignBit = DAG.getNode(ISD::SHL, DL, MagVT, SignBit, ShiftCnst);
}
ShiftVT = MagVT;
}
if (ShiftAmount > 0) {
SDValue ShiftCnst = DAG.getConstant(ShiftAmount, DL, ShiftVT);
SignBit = DAG.getNode(ISD::SRL, DL, ShiftVT, SignBit, ShiftCnst);
} else if (ShiftAmount < 0) {
SDValue ShiftCnst = DAG.getConstant(-ShiftAmount, DL, ShiftVT);
SignBit = DAG.getNode(ISD::SHL, DL, ShiftVT, SignBit, ShiftCnst);
}
if (SignBit.getValueSizeInBits() > ClearedSign.getValueSizeInBits()) {
SignBit = DAG.getNode(ISD::TRUNCATE, DL, MagVT, SignBit);
}
// Store the part with the modified sign and convert back to float.

25
llvm/test/CodeGen/AArch64/fcopysign.ll
View File

@ -5,10 +5,12 @@ target triple = "aarch64--"
declare fp128 @llvm.copysign.f128(fp128, fp128)
@val = global double zeroinitializer, align 8
@val_float = global float zeroinitializer, align 4
@val_double = global double zeroinitializer, align 8
@val_fp128 = global fp128 zeroinitializer, align 16
; CHECK-LABEL: copysign0
; CHECK: ldr [[REG:x[0-9]+]], [x8, :lo12:val]
; CHECK: ldr [[REG:x[0-9]+]], [x8, :lo12:val_double]
; CHECK: and [[ANDREG:x[0-9]+]], [[REG]], #0x8000000000000000
; CHECK: lsr x[[LSRREGNUM:[0-9]+]], [[ANDREG]], #56
; CHECK: bfxil w[[LSRREGNUM]], w{{[0-9]+}}, #0, #7
@ -16,8 +18,25 @@ declare fp128 @llvm.copysign.f128(fp128, fp128)
; CHECK: ldr q{{[0-9]+}},
define fp128 @copysign0() {
entry:
%v = load double, double* @val, align 8
%v = load double, double* @val_double, align 8
%conv = fpext double %v to fp128
%call = tail call fp128 @llvm.copysign.f128(fp128 0xL00000000000000007FFF000000000000, fp128 %conv) #2
ret fp128 %call
}
; CHECK-LABEL: copysign1
; CHECK-DAG: ldr [[REG:q[0-9]+]], [x8, :lo12:val_fp128]
; CHECK-DAG: ldr [[REG:w[0-9]+]], [x8, :lo12:val_float]
; CHECK: and [[ANDREG:w[0-9]+]], [[REG]], #0x80000000
; CHECK: lsr w[[LSRREGNUM:[0-9]+]], [[ANDREG]], #24
; CHECK: bfxil w[[LSRREGNUM]], w{{[0-9]+}}, #0, #7
; CHECK: strb w[[LSRREGNUM]],
; CHECK: ldr q{{[0-9]+}},
define fp128@copysign1() {
entry:
%v0 = load fp128, fp128* @val_fp128, align 16
%v1 = load float, float* @val_float, align 4
%conv = fpext float %v1 to fp128
%call = tail call fp128 @llvm.copysign.f128(fp128 %v0, fp128 %conv)
ret fp128 %call
}