Add ISD::isBuildVectorAllZeros predicate
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@27147 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/include/llvm/CodeGen/SelectionDAGNodes.h b/include/llvm/CodeGen/SelectionDAGNodes.h
index df76524..4863940 100644
--- a/include/llvm/CodeGen/SelectionDAGNodes.h
+++ b/include/llvm/CodeGen/SelectionDAGNodes.h
@@ -458,7 +458,10 @@
/// isBuildVectorAllOnesInteger - Return true if the specified node is a
/// BUILD_VECTOR where all of the elements are ~0 or undef.
bool isBuildVectorAllOnesInteger(const SDNode *N);
-
+
+ /// isBuildVectorAllZeros - Return true if the specified node is a
+ /// BUILD_VECTOR where all of the elements are 0 or undef.
+ bool isBuildVectorAllZeros(const SDNode *N);
//===--------------------------------------------------------------------===//
/// ISD::CondCode enum - These are ordered carefully to make the bitfields
diff --git a/lib/CodeGen/SelectionDAG/SelectionDAG.cpp b/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
index 18e2ebc..c0cd646 100644
--- a/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
+++ b/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
@@ -101,6 +101,30 @@
}
+/// isBuildVectorAllZeros - Return true if the specified node is a
+/// BUILD_VECTOR where all of the elements are 0 or undef.
+bool ISD::isBuildVectorAllZeros(const SDNode *N) {
+ if (N->getOpcode() != ISD::BUILD_VECTOR) return false;
+
+ bool AllUndef = true;
+ for (unsigned i = 0, e = N->getNumOperands(); i != e; ++i) {
+ SDOperand Elt = N->getOperand(i);
+ if (Elt.getOpcode() != ISD::UNDEF) {
+ AllUndef = false;
+ if (isa<ConstantSDNode>(Elt)) {
+ if (!cast<ConstantSDNode>(Elt)->isNullValue())
+ return false;
+ } else if (isa<ConstantFPSDNode>(Elt)) {
+ if (!cast<ConstantFPSDNode>(Elt)->isExactlyValue(0.0))
+ return false;
+ } else
+ return false;
+ }
+ }
+
+ return !AllUndef;
+}
+
/// getSetCCSwappedOperands - Return the operation corresponding to (Y op X)
/// when given the operation for (X op Y).
ISD::CondCode ISD::getSetCCSwappedOperands(ISD::CondCode Operation) {