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X86: When emulating unsigned PCMPGTQ with PCMPGTD, fix the sign bit for the smaller type.

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Otherwise we'll get a mix of signed and unsigned compares.
Fixes PR15977.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@182364 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Benjamin Kramer 2013-05-21 09:58:54 +00:00
parent af2a1bebfc
commit f106d8bad6
2 changed files with 27 additions and 17 deletions
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34
lib/Target/X86/X86ISelLowering.cpp
View File

@ -9347,29 +9347,24 @@ static SDValue LowerVSETCC(SDValue Op, const X86Subtarget *Subtarget,
if (Swap)
std::swap(Op0, Op1);
// Since SSE has no unsigned integer comparisons, we need to flip the sign
// bits of the inputs before performing those operations.
if (FlipSigns) {
EVT EltVT = VT.getVectorElementType();
SDValue SignBit = DAG.getConstant(APInt::getSignBit(EltVT.getSizeInBits()),
EltVT);
std::vector<SDValue> SignBits(VT.getVectorNumElements(), SignBit);
SDValue SignVec = DAG.getNode(ISD::BUILD_VECTOR, dl, VT, &SignBits[0],
SignBits.size());
Op0 = DAG.getNode(ISD::XOR, dl, VT, Op0, SignVec);
Op1 = DAG.getNode(ISD::XOR, dl, VT, Op1, SignVec);
}
// Check that the operation in question is available (most are plain SSE2,
// but PCMPGTQ and PCMPEQQ have different requirements).
if (VT == MVT::v2i64) {
if (Opc == X86ISD::PCMPGT && !Subtarget->hasSSE42()) {
assert(Subtarget->hasSSE2() && "Don't know how to lower!");
// First cast everything to the right type,
// First cast everything to the right type.
Op0 = DAG.getNode(ISD::BITCAST, dl, MVT::v4i32, Op0);
Op1 = DAG.getNode(ISD::BITCAST, dl, MVT::v4i32, Op1);
// Since SSE has no unsigned integer comparisons, we need to flip the sign
// bits of the inputs before performing those operations.
if (FlipSigns) {
SDValue SB = DAG.getConstant(0x80000000U, MVT::v4i32);
Op0 = DAG.getNode(ISD::XOR, dl, MVT::v4i32, Op0, SB);
Op1 = DAG.getNode(ISD::XOR, dl, MVT::v4i32, Op1, SB);
}
// Emulate PCMPGTQ with (hi1 > hi2) | ((hi1 == hi2) & (lo1 > lo2))
SDValue GT = DAG.getNode(X86ISD::PCMPGT, dl, MVT::v4i32, Op0, Op1);
SDValue EQ = DAG.getNode(X86ISD::PCMPEQ, dl, MVT::v4i32, Op0, Op1);
@ -9395,7 +9390,7 @@ static SDValue LowerVSETCC(SDValue Op, const X86Subtarget *Subtarget,
// pcmpeqd + pshufd + pand.
assert(Subtarget->hasSSE2() && !FlipSigns && "Don't know how to lower!");
// First cast everything to the right type,
// First cast everything to the right type.
Op0 = DAG.getNode(ISD::BITCAST, dl, MVT::v4i32, Op0);
Op1 = DAG.getNode(ISD::BITCAST, dl, MVT::v4i32, Op1);
@ -9414,6 +9409,15 @@ static SDValue LowerVSETCC(SDValue Op, const X86Subtarget *Subtarget,
}
}
// Since SSE has no unsigned integer comparisons, we need to flip the sign
// bits of the inputs before performing those operations.
if (FlipSigns) {
EVT EltVT = VT.getVectorElementType();
SDValue SB = DAG.getConstant(APInt::getSignBit(EltVT.getSizeInBits()), VT);
Op0 = DAG.getNode(ISD::XOR, dl, VT, Op0, SB);
Op1 = DAG.getNode(ISD::XOR, dl, VT, Op1, SB);
}
SDValue Result = DAG.getNode(Opc, dl, VT, Op0, Op1);
// If the logical-not of the result is required, perform that now.

10
test/CodeGen/X86/vec_compare.ll
View File

@ -131,9 +131,15 @@ define <2 x i64> @test10(<2 x i64> %A, <2 x i64> %B) nounwind {
}
define <2 x i64> @test11(<2 x i64> %A, <2 x i64> %B) nounwind {
; CHECK: [[CONSTSEG:[A-Z0-9_]*]]:
; CHECK: .long 2147483648
; CHECK-NEXT: .long 2147483648
; CHECK-NEXT: .long 2147483648
; CHECK-NEXT: .long 2147483648
; CHECK: test11:
; CHECK: pxor
; CHECK: pxor
; CHECK: movdqa [[CONSTSEG]], [[CONSTREG:%xmm[0-9]*]]
; CHECK: pxor [[CONSTREG]]
; CHECK: pxor [[CONSTREG]]
; CHECK: pcmpgtd %xmm1
; CHECK: pshufd $-96
; CHECK: pcmpeqd