Always compute all the bits in ComputeMaskedBits.

This allows us to keep passing reduced masks to SimplifyDemandedBits, but
know about all the bits if SimplifyDemandedBits fails. This allows instcombine
to simplify cases like the one in the included testcase.

llvm-svn: 154011

1 files changed, 3 insertions, 6 deletions

diff --git a/llvm/lib/Target/Sparc/SparcISelLowering.cpp b/llvm/lib/Target/Sparc/SparcISelLowering.cpp
index ee126331308..c3e6f160679 100644
--- a/llvm/lib/Target/Sparc/SparcISelLowering.cpp
+++ b/llvm/lib/Target/Sparc/SparcISelLowering.cpp
@@ -832,22 +832,19 @@ const char *SparcTargetLowering::getTargetNodeName(unsigned Opcode) const {
 /// be zero. Op is expected to be a target specific node. Used by DAG
 /// combiner.
 void SparcTargetLowering::computeMaskedBitsForTargetNode(const SDValue Op,
-                                                         const APInt &Mask,
                                                          APInt &KnownZero,
                                                          APInt &KnownOne,
                                                          const SelectionDAG &DAG,
                                                          unsigned Depth) const {
   APInt KnownZero2, KnownOne2;
-  KnownZero = KnownOne = APInt(Mask.getBitWidth(), 0);   // Don't know anything.
+  KnownZero = KnownOne = APInt(KnownZero.getBitWidth(), 0);
 
   switch (Op.getOpcode()) {
   default: break;
   case SPISD::SELECT_ICC:
   case SPISD::SELECT_FCC:
-    DAG.ComputeMaskedBits(Op.getOperand(1), Mask, KnownZero, KnownOne,
-                          Depth+1);
-    DAG.ComputeMaskedBits(Op.getOperand(0), Mask, KnownZero2, KnownOne2,
-                          Depth+1);
+    DAG.ComputeMaskedBits(Op.getOperand(1), KnownZero, KnownOne, Depth+1);
+    DAG.ComputeMaskedBits(Op.getOperand(0), KnownZero2, KnownOne2, Depth+1);
     assert((KnownZero & KnownOne) == 0 && "Bits known to be one AND zero?");
     assert((KnownZero2 & KnownOne2) == 0 && "Bits known to be one AND zero?");