Some dag combiner goodness:
Transform br (xor (x, y)) -> br (x != y)
Transform br (xor (xor (x,y), 1)) -> br (x == y)
Also normalize (and (X, 1) == / != 1 -> (and (X, 1)) != / == 0 to match to "test on x86" and "tst on arm"
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@96556 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/SelectionDAG/DAGCombiner.cpp b/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
index 7da7848..c5dba39 100644
--- a/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
+++ b/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
@@ -4655,7 +4655,8 @@
DAG.DeleteNode(Trunc);
}
// Replace the uses of SRL with SETCC
- DAG.ReplaceAllUsesOfValueWith(N1, SetCC);
+ WorkListRemover DeadNodes(*this);
+ DAG.ReplaceAllUsesOfValueWith(N1, SetCC, &DeadNodes);
removeFromWorkList(N1.getNode());
DAG.DeleteNode(N1.getNode());
return SDValue(N, 0); // Return N so it doesn't get rechecked!
@@ -4663,6 +4664,53 @@
}
}
}
+
+ // Transform br(xor(x, y)) -> br(x != y)
+ // Transform br(xor(xor(x,y), 1)) -> br (x == y)
+ if (N1.hasOneUse() && N1.getOpcode() == ISD::XOR) {
+ SDNode *TheXor = N1.getNode();
+ SDValue Op0 = TheXor->getOperand(0);
+ SDValue Op1 = TheXor->getOperand(1);
+ if (Op0.getOpcode() == Op1.getOpcode()) {
+ // Avoid missing important xor optimizations.
+ SDValue Tmp = visitXOR(TheXor);
+ if (Tmp.getNode()) {
+ DEBUG(dbgs() << "\nReplacing.8 ";
+ TheXor->dump(&DAG);
+ dbgs() << "\nWith: ";
+ Tmp.getNode()->dump(&DAG);
+ dbgs() << '\n');
+ WorkListRemover DeadNodes(*this);
+ DAG.ReplaceAllUsesOfValueWith(N1, Tmp, &DeadNodes);
+ removeFromWorkList(TheXor);
+ DAG.DeleteNode(TheXor);
+ return DAG.getNode(ISD::BRCOND, N->getDebugLoc(),
+ MVT::Other, Chain, Tmp, N2);
+ }
+ }
+
+ if (Op0.getOpcode() != ISD::SETCC && Op1.getOpcode() != ISD::SETCC) {
+ bool Equal = false;
+ if (ConstantSDNode *RHSCI = dyn_cast<ConstantSDNode>(Op0))
+ if (RHSCI->getAPIntValue() == 1 && Op0.hasOneUse() &&
+ Op0.getOpcode() == ISD::XOR) {
+ TheXor = Op0.getNode();
+ Equal = true;
+ }
+
+ SDValue SetCC = DAG.getSetCC(TheXor->getDebugLoc(),
+ TLI.getSetCCResultType(N1.getValueType()),
+ Op0, Op1,
+ Equal ? ISD::SETEQ : ISD::SETNE);
+ // Replace the uses of XOR with SETCC
+ WorkListRemover DeadNodes(*this);
+ DAG.ReplaceAllUsesOfValueWith(N1, SetCC, &DeadNodes);
+ removeFromWorkList(N1.getNode());
+ DAG.DeleteNode(N1.getNode());
+ return DAG.getNode(ISD::BRCOND, N->getDebugLoc(),
+ MVT::Other, Chain, SetCC, N2);
+ }
+ }
return SDValue();
}
@@ -5012,7 +5060,7 @@
assert(N->getValueType(2) == MVT::Other && "Malformed indexed loads?");
if (N->hasNUsesOfValue(0, 0) && N->hasNUsesOfValue(0, 1)) {
SDValue Undef = DAG.getUNDEF(N->getValueType(0));
- DEBUG(dbgs() << "\nReplacing.6 ";
+ DEBUG(dbgs() << "\nReplacing.7 ";
N->dump(&DAG);
dbgs() << "\nWith: ";
Undef.getNode()->dump(&DAG);
diff --git a/lib/CodeGen/SelectionDAG/TargetLowering.cpp b/lib/CodeGen/SelectionDAG/TargetLowering.cpp
index e88af4f..9f9d8b0 100644
--- a/lib/CodeGen/SelectionDAG/TargetLowering.cpp
+++ b/lib/CodeGen/SelectionDAG/TargetLowering.cpp
@@ -1775,7 +1775,7 @@
break; // todo, be more careful with signed comparisons
}
} else if (N0.getOpcode() == ISD::SIGN_EXTEND_INREG &&
- (Cond == ISD::SETEQ || Cond == ISD::SETNE)) {
+ (Cond == ISD::SETEQ || Cond == ISD::SETNE)) {
EVT ExtSrcTy = cast<VTSDNode>(N0.getOperand(1))->getVT();
unsigned ExtSrcTyBits = ExtSrcTy.getSizeInBits();
EVT ExtDstTy = N0.getValueType();
@@ -1809,7 +1809,6 @@
Cond);
} else if ((N1C->isNullValue() || N1C->getAPIntValue() == 1) &&
(Cond == ISD::SETEQ || Cond == ISD::SETNE)) {
-
// SETCC (SETCC), [0|1], [EQ|NE] -> SETCC
if (N0.getOpcode() == ISD::SETCC) {
bool TrueWhenTrue = (Cond == ISD::SETEQ) ^ (N1C->getAPIntValue() != 1);
@@ -1822,9 +1821,9 @@
N0.getOperand(0).getValueType().isInteger());
return DAG.getSetCC(dl, VT, N0.getOperand(0), N0.getOperand(1), CC);
}
-
+
if ((N0.getOpcode() == ISD::XOR ||
- (N0.getOpcode() == ISD::AND &&
+ (N0.getOpcode() == ISD::AND &&
N0.getOperand(0).getOpcode() == ISD::XOR &&
N0.getOperand(1) == N0.getOperand(0).getOperand(1))) &&
isa<ConstantSDNode>(N0.getOperand(1)) &&
@@ -1847,9 +1846,26 @@
N0.getOperand(0).getOperand(0),
N0.getOperand(1));
}
+
return DAG.getSetCC(dl, VT, Val, N1,
Cond == ISD::SETEQ ? ISD::SETNE : ISD::SETEQ);
}
+ } else if (N1C->getAPIntValue() == 1) {
+ // If this is (X&1) == / != 1, normalize it to (X&1) != / == 0.
+ SDValue Op0 = N0;
+ if (Op0.getOpcode() == ISD::TRUNCATE)
+ Op0 = Op0.getOperand(0);
+ if (Op0.getOpcode() == ISD::AND &&
+ isa<ConstantSDNode>(Op0.getOperand(1)) &&
+ cast<ConstantSDNode>(Op0.getOperand(1))->getAPIntValue() == 1) {
+ if (Op0.getValueType() != VT)
+ Op0 = DAG.getNode(ISD::AND, dl, VT,
+ DAG.getNode(ISD::TRUNCATE, dl, VT, Op0.getOperand(0)),
+ DAG.getConstant(1, VT));
+ return DAG.getSetCC(dl, VT, Op0,
+ DAG.getConstant(0, Op0.getValueType()),
+ Cond == ISD::SETEQ ? ISD::SETNE : ISD::SETEQ);
+ }
}
}
diff --git a/lib/Target/X86/X86ISelLowering.cpp b/lib/Target/X86/X86ISelLowering.cpp
index 4c40fe1..7b203f2 100644
--- a/lib/Target/X86/X86ISelLowering.cpp
+++ b/lib/Target/X86/X86ISelLowering.cpp
@@ -5874,26 +5874,31 @@
/// LowerToBT - Result of 'and' is compared against zero. Turn it into a BT node
/// if it's possible.
-static SDValue LowerToBT(SDValue Op0, ISD::CondCode CC,
+static SDValue LowerToBT(SDValue And, ISD::CondCode CC,
DebugLoc dl, SelectionDAG &DAG) {
+ SDValue Op0 = And.getOperand(0);
+ SDValue Op1 = And.getOperand(1);
+ if (Op0.getOpcode() == ISD::TRUNCATE)
+ Op0 = Op0.getOperand(0);
+ if (Op1.getOpcode() == ISD::TRUNCATE)
+ Op1 = Op1.getOperand(0);
+
SDValue LHS, RHS;
- if (Op0.getOperand(1).getOpcode() == ISD::SHL) {
- if (ConstantSDNode *Op010C =
- dyn_cast<ConstantSDNode>(Op0.getOperand(1).getOperand(0)))
- if (Op010C->getZExtValue() == 1) {
- LHS = Op0.getOperand(0);
- RHS = Op0.getOperand(1).getOperand(1);
+ if (Op1.getOpcode() == ISD::SHL) {
+ if (ConstantSDNode *And10C = dyn_cast<ConstantSDNode>(Op1.getOperand(0)))
+ if (And10C->getZExtValue() == 1) {
+ LHS = Op0;
+ RHS = Op1.getOperand(1);
}
- } else if (Op0.getOperand(0).getOpcode() == ISD::SHL) {
- if (ConstantSDNode *Op000C =
- dyn_cast<ConstantSDNode>(Op0.getOperand(0).getOperand(0)))
- if (Op000C->getZExtValue() == 1) {
- LHS = Op0.getOperand(1);
- RHS = Op0.getOperand(0).getOperand(1);
+ } else if (Op0.getOpcode() == ISD::SHL) {
+ if (ConstantSDNode *And00C = dyn_cast<ConstantSDNode>(Op0.getOperand(0)))
+ if (And00C->getZExtValue() == 1) {
+ LHS = Op1;
+ RHS = Op0.getOperand(1);
}
- } else if (Op0.getOperand(1).getOpcode() == ISD::Constant) {
- ConstantSDNode *AndRHS = cast<ConstantSDNode>(Op0.getOperand(1));
- SDValue AndLHS = Op0.getOperand(0);
+ } else if (Op1.getOpcode() == ISD::Constant) {
+ ConstantSDNode *AndRHS = cast<ConstantSDNode>(Op1);
+ SDValue AndLHS = Op0;
if (AndRHS->getZExtValue() == 1 && AndLHS.getOpcode() == ISD::SRL) {
LHS = AndLHS.getOperand(0);
RHS = AndLHS.getOperand(1);
@@ -5943,6 +5948,17 @@
return NewSetCC;
}
+ // Look for "(setcc) == / != 1" to avoid unncessary setcc.
+ if (Op0.getOpcode() == X86ISD::SETCC &&
+ Op1.getOpcode() == ISD::Constant &&
+ cast<ConstantSDNode>(Op1)->getZExtValue() == 1 &&
+ (CC == ISD::SETEQ || CC == ISD::SETNE)) {
+ X86::CondCode CCode = (X86::CondCode)Op0.getConstantOperandVal(0);
+ CCode = X86::GetOppositeBranchCondition(CCode);
+ return DAG.getNode(X86ISD::SETCC, dl, MVT::i8,
+ DAG.getConstant(CCode, MVT::i8), Op0.getOperand(1));
+ }
+
bool isFP = Op.getOperand(1).getValueType().isFloatingPoint();
unsigned X86CC = TranslateX86CC(CC, isFP, Op0, Op1, DAG);
if (X86CC == X86::COND_INVALID)