Add helpers for checking if a value is a target boolean constant.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@205335 91177308-0d34-0410-b5e6-96231b3b80d8

2 files changed, 56 insertions, 0 deletions

diff --git a/include/llvm/Target/TargetLowering.h b/include/llvm/Target/TargetLowering.h
index 06cc75f4d3..2f6445fb7a 100644
--- a/include/llvm/Target/TargetLowering.h
+++ b/include/llvm/Target/TargetLowering.h
@@ -1934,6 +1934,14 @@ public:
     void CommitTargetLoweringOpt(const TargetLoweringOpt &TLO);
   };
 
+  /// Return if the N is a constant or constant vector equal to the true value
+  /// from getBooleanContents().
+  bool isConstTrueVal(const SDNode *N) const;
+
+  /// Return if the N is a constant or constant vector equal to the false value
+  /// from getBooleanContents().
+  bool isConstFalseVal(const SDNode *N) const;
+
   /// Try to simplify a setcc built with the specified operands and cc. If it is
   /// unable to simplify it, return a null SDValue.
   SDValue SimplifySetCC(EVT VT, SDValue N0, SDValue N1,
diff --git a/lib/CodeGen/SelectionDAG/TargetLowering.cpp b/lib/CodeGen/SelectionDAG/TargetLowering.cpp
index 115129ec3a..5de0b030c7 100644
--- a/lib/CodeGen/SelectionDAG/TargetLowering.cpp
+++ b/lib/CodeGen/SelectionDAG/TargetLowering.cpp
@@ -1117,6 +1117,54 @@ static bool ValueHasExactlyOneBitSet(SDValue Val, const SelectionDAG &DAG) {
          (KnownOne.countPopulation() == 1);
 }
 
+bool TargetLowering::isConstTrueVal(const SDNode *N) const {
+  if (!N)
+    return false;
+
+  bool IsVec = false;
+  const ConstantSDNode *CN = dyn_cast<ConstantSDNode>(N);
+  if (!CN) {
+    const BuildVectorSDNode *BV = dyn_cast<BuildVectorSDNode>(N);
+    if (!BV)
+      return false;
+
+    IsVec = true;
+    CN = BV->getConstantSplatValue();
+  }
+
+  switch (getBooleanContents(IsVec)) {
+  case UndefinedBooleanContent:
+    return CN->getAPIntValue()[0];
+  case ZeroOrOneBooleanContent:
+    return CN->isOne();
+  case ZeroOrNegativeOneBooleanContent:
+    return CN->isAllOnesValue();
+  }
+
+  llvm_unreachable("Invalid boolean contents");
+}
+
+bool TargetLowering::isConstFalseVal(const SDNode *N) const {
+  if (!N)
+    return false;
+
+  bool IsVec = false;
+  const ConstantSDNode *CN = dyn_cast<ConstantSDNode>(N);
+  if (!CN) {
+    const BuildVectorSDNode *BV = dyn_cast<BuildVectorSDNode>(N);
+    if (!BV)
+      return false;
+
+    IsVec = true;
+    CN = BV->getConstantSplatValue();
+  }
+
+  if (getBooleanContents(IsVec) == UndefinedBooleanContent)
+    return !CN->getAPIntValue()[0];
+
+  return CN->isNullValue();
+}
+
 /// SimplifySetCC - Try to simplify a setcc built with the specified operands
 /// and cc. If it is unable to simplify it, return a null SDValue.
 SDValue