[SelectionDAG] MaskedValueIsZero - add demanded elements implementation

Will be used in an upcoming patch but I've updated the original implementation to call this to ensure test coverage.

llvm-svn: 361738

1 files changed, 15 insertions, 2 deletions

diff --git a/llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp b/llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
index 553a46f6ec1..88cbfd1d69f 100644
--- a/llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
+++ b/llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
@@ -2207,9 +2207,22 @@ bool SelectionDAG::SignBitIsZero(SDValue Op, unsigned Depth) const {
 /// MaskedValueIsZero - Return true if 'V & Mask' is known to be zero.  We use
 /// this predicate to simplify operations downstream.  Mask is known to be zero
 /// for bits that V cannot have.
-bool SelectionDAG::MaskedValueIsZero(SDValue Op, const APInt &Mask,
+bool SelectionDAG::MaskedValueIsZero(SDValue V, const APInt &Mask,
                                      unsigned Depth) const {
-  return Mask.isSubsetOf(computeKnownBits(Op, Depth).Zero);
+  EVT VT = V.getValueType();
+  APInt DemandedElts = VT.isVector()
+                           ? APInt::getAllOnesValue(VT.getVectorNumElements())
+                           : APInt(1, 1);
+  return MaskedValueIsZero(V, Mask, DemandedElts, Depth);
+}
+
+/// MaskedValueIsZero - Return true if 'V & Mask' is known to be zero in
+/// DemandedElts.  We use this predicate to simplify operations downstream.
+/// Mask is known to be zero for bits that V cannot have.
+bool SelectionDAG::MaskedValueIsZero(SDValue V, const APInt &Mask,
+                                     const APInt &DemandedElts,
+                                     unsigned Depth) const {
+  return Mask.isSubsetOf(computeKnownBits(V, DemandedElts, Depth).Zero);
 }
 
 /// isSplatValue - Return true if the vector V has the same value