Implement the ISD::isBuildVectorAllOnesInteger predicate
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@27130 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/SelectionDAG/SelectionDAG.cpp b/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
index 97b4095..9fcfc61 100644
--- a/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
+++ b/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
@@ -66,9 +66,40 @@
}
//===----------------------------------------------------------------------===//
-// ISD Class
+// ISD Namespace
//===----------------------------------------------------------------------===//
+/// isBuildVectorAllOnesInteger - Return true if the specified node is a
+/// BUILD_VECTOR where all of the elements are ~0 or undef.
+bool ISD::isBuildVectorAllOnesInteger(const SDNode *N) {
+ if (N->getOpcode() != ISD::BUILD_VECTOR ||
+ !MVT::isInteger(N->getOperand(0).getValueType())) return false;
+
+ unsigned i = 0, e = N->getNumOperands();
+
+ // Skip over all of the undef values.
+ while (i != e && N->getOperand(i).getOpcode() == ISD::UNDEF)
+ ++i;
+
+ // Do not accept an all-undef vector.
+ if (i == e) return false;
+
+ // Do not accept build_vectors that aren't all constants or which have non-~0
+ // elements.
+ if (!isa<ConstantSDNode>(N) || !cast<ConstantSDNode>(N)->isAllOnesValue())
+ return false;
+
+ // Okay, we have at least one ~0 value, check to see if the rest match or are
+ // undefs.
+ SDOperand NotZero = N->getOperand(i);
+ for (++i; i != e; ++i)
+ if (N->getOperand(i) != NotZero &&
+ N->getOperand(i).getOpcode() != ISD::UNDEF)
+ return false;
+ return true;
+}
+
+
/// getSetCCSwappedOperands - Return the operation corresponding to (Y op X)
/// when given the operation for (X op Y).
ISD::CondCode ISD::getSetCCSwappedOperands(ISD::CondCode Operation) {