Look for SSE and instructions of this form: (and x, (build_vector c1,c2,c3,c4)).
If there exists a use of a build_vector that's the bitwise complement of the mask,
then transform the node to
(and (xor x, (build_vector -1,-1,-1,-1)), (build_vector ~c1,~c2,~c3,~c4)).
Since this transformation is only useful when 1) the given build_vector will
become a load from constpool, and 2) (and (xor x -1), y) matches to a single
instruction, I decided this is appropriate as a x86 specific transformation.
rdar://7323335
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@96389 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Target/X86/X86ISelLowering.cpp b/lib/Target/X86/X86ISelLowering.cpp
index 9974d8c..4c40fe1 100644
--- a/lib/Target/X86/X86ISelLowering.cpp
+++ b/lib/Target/X86/X86ISelLowering.cpp
@@ -990,6 +990,7 @@
setTargetDAGCombine(ISD::VECTOR_SHUFFLE);
setTargetDAGCombine(ISD::BUILD_VECTOR);
setTargetDAGCombine(ISD::SELECT);
+ setTargetDAGCombine(ISD::AND);
setTargetDAGCombine(ISD::SHL);
setTargetDAGCombine(ISD::SRA);
setTargetDAGCombine(ISD::SRL);
@@ -9157,6 +9158,53 @@
return SDValue();
}
+/// PerformANDCombine - Look for SSE and instructions of this form:
+/// (and x, (build_vector c1,c2,c3,c4)). If there exists a use of a build_vector
+/// that's the bitwise complement of the mask, then transform the node to
+/// (and (xor x, (build_vector -1,-1,-1,-1)), (build_vector ~c1,~c2,~c3,~c4)).
+static SDValue PerformANDCombine(SDNode *N, SelectionDAG &DAG,
+ TargetLowering::DAGCombinerInfo &DCI) {
+ EVT VT = N->getValueType(0);
+ if (!VT.isVector() || !VT.isInteger())
+ return SDValue();
+
+ SDValue N0 = N->getOperand(0);
+ SDValue N1 = N->getOperand(1);
+ if (N0.getOpcode() == ISD::XOR || !N1.hasOneUse())
+ return SDValue();
+
+ if (N1.getOpcode() == ISD::BUILD_VECTOR) {
+ unsigned NumElts = VT.getVectorNumElements();
+ EVT EltVT = VT.getVectorElementType();
+ SmallVector<SDValue, 8> Mask;
+ Mask.reserve(NumElts);
+ for (unsigned i = 0; i != NumElts; ++i) {
+ SDValue Arg = N1.getOperand(i);
+ if (Arg.getOpcode() == ISD::UNDEF) {
+ Mask.push_back(Arg);
+ continue;
+ }
+ ConstantSDNode *C = dyn_cast<ConstantSDNode>(Arg);
+ if (!C) return SDValue();
+ Mask.push_back(DAG.getConstant(~C->getAPIntValue(), EltVT));
+ }
+ N1 = DAG.getNode(ISD::BUILD_VECTOR, N1.getDebugLoc(), VT,
+ &Mask[0], NumElts);
+ if (!N1.use_empty()) {
+ unsigned Bits = EltVT.getSizeInBits();
+ Mask.clear();
+ for (unsigned i = 0; i != NumElts; ++i)
+ Mask.push_back(DAG.getConstant(APInt::getAllOnesValue(Bits), EltVT));
+ SDValue NewMask = DAG.getNode(ISD::BUILD_VECTOR, N->getDebugLoc(),
+ VT, &Mask[0], NumElts);
+ return DAG.getNode(ISD::AND, N->getDebugLoc(), VT,
+ DAG.getNode(ISD::XOR, N->getDebugLoc(), VT,
+ N0, NewMask), N1);
+ }
+ }
+
+ return SDValue();
+}
/// PerformMulCombine - Optimize a single multiply with constant into two
/// in order to implement it with two cheaper instructions, e.g.
@@ -9305,7 +9353,7 @@
}
} else if (InVec.getOpcode() == ISD::INSERT_VECTOR_ELT) {
if (ConstantSDNode *C = dyn_cast<ConstantSDNode>(InVec.getOperand(2))) {
- unsigned SplatIdx = cast<ShuffleVectorSDNode>(ShAmtOp)->getSplatIndex();
+ unsigned SplatIdx= cast<ShuffleVectorSDNode>(ShAmtOp)->getSplatIndex();
if (C->getZExtValue() == SplatIdx)
BaseShAmt = InVec.getOperand(1);
}
@@ -9690,6 +9738,7 @@
case ISD::VECTOR_SHUFFLE: return PerformShuffleCombine(N, DAG, *this);
case ISD::SELECT: return PerformSELECTCombine(N, DAG, Subtarget);
case X86ISD::CMOV: return PerformCMOVCombine(N, DAG, DCI);
+ case ISD::AND: return PerformANDCombine(N, DAG, DCI);
case ISD::MUL: return PerformMulCombine(N, DAG, DCI);
case ISD::SHL:
case ISD::SRA: