SelectionDAG: Improve legalization of SELECT_CC with illegal condition codes
SelectionDAG will now attempt to inverse an illegal conditon in order to
find a legal one and if that doesn't work, it will attempt to swap the
operands using the inverted condition.
There are no new test cases for this, but a nubmer of the existing R600
tests hit this path.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@191602 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/SelectionDAG/LegalizeDAG.cpp b/lib/CodeGen/SelectionDAG/LegalizeDAG.cpp
index f6406b2..e78caba 100644
--- a/lib/CodeGen/SelectionDAG/LegalizeDAG.cpp
+++ b/lib/CodeGen/SelectionDAG/LegalizeDAG.cpp
@@ -3664,20 +3664,44 @@
Tmp4 = Node->getOperand(3); // False
SDValue CC = Node->getOperand(4);
- bool Legalized = LegalizeSetCCCondCode(
- getSetCCResultType(Tmp1.getValueType()), Tmp1, Tmp2, CC, dl);
-
- assert(Legalized && "Can't legalize SELECT_CC with legal condition!");
- // If we exapanded the SETCC by swapping LHS and RHS, create a new SELECT_CC
- // node and return it.
- if (CC.getNode()) {
- Tmp1 = DAG.getNode(ISD::SELECT_CC, dl, Node->getValueType(0),
- Tmp1, Tmp2, Tmp3, Tmp4, CC);
+ bool Legalized = false;
+ // Try to legalize by inverting the condition. This is for targets that
+ // might support an ordered version of a condition, but not the unordered
+ // version (or vice versa).
+ ISD::CondCode InvCC = ISD::getSetCCInverse(cast<CondCodeSDNode>(CC)->get(),
+ Tmp1.getValueType().isInteger());
+ if (TLI.isCondCodeLegal(InvCC, Tmp1.getSimpleValueType())) {
+ // Use the new condition code and swap true and false
+ Legalized = true;
+ Tmp1 = DAG.getSelectCC(dl, Tmp1, Tmp2, Tmp4, Tmp3, InvCC);
} else {
- Tmp2 = DAG.getConstant(0, Tmp1.getValueType());
- CC = DAG.getCondCode(ISD::SETNE);
- Tmp1 = DAG.getNode(ISD::SELECT_CC, dl, Node->getValueType(0), Tmp1, Tmp2,
- Tmp3, Tmp4, CC);
+ // If The inverse is not legal, then try to swap the arguments using
+ // the inverse condition code.
+ ISD::CondCode SwapInvCC = ISD::getSetCCSwappedOperands(InvCC);
+ if (TLI.isCondCodeLegal(SwapInvCC, Tmp1.getSimpleValueType())) {
+ // The swapped inverse condition is legal, so swap true and false,
+ // lhs and rhs.
+ Legalized = true;
+ Tmp1 = DAG.getSelectCC(dl, Tmp2, Tmp1, Tmp4, Tmp3, SwapInvCC);
+ }
+ }
+
+ if (!Legalized) {
+ Legalized = LegalizeSetCCCondCode(
+ getSetCCResultType(Tmp1.getValueType()), Tmp1, Tmp2, CC, dl);
+
+ assert(Legalized && "Can't legalize SELECT_CC with legal condition!");
+ // If we exapanded the SETCC by swapping LHS and RHS, create a new
+ // SELECT_CC node.
+ if (CC.getNode()) {
+ Tmp1 = DAG.getNode(ISD::SELECT_CC, dl, Node->getValueType(0),
+ Tmp1, Tmp2, Tmp3, Tmp4, CC);
+ } else {
+ Tmp2 = DAG.getConstant(0, Tmp1.getValueType());
+ CC = DAG.getCondCode(ISD::SETNE);
+ Tmp1 = DAG.getNode(ISD::SELECT_CC, dl, Node->getValueType(0), Tmp1, Tmp2,
+ Tmp3, Tmp4, CC);
+ }
}
Results.push_back(Tmp1);
break;