[SelectionDAG] computeKnownBits/ComputeNumSignBits - cleanup demanded/unknown paths...

Merge the calls, just adjust the demandedelts if we have a valid extract_subvector constant index, else demand all elts.

llvm-svn: 372521

diff --git a/llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp b/llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
index 95b7fe2..1dcac7a 100644 (file)
--- a/llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
+++ b/llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
@@ -2567,14 +2567,13 @@ KnownBits SelectionDAG::computeKnownBits(SDValue Op, const APInt &DemandedElts,
     SDValue Src = Op.getOperand(0);
     ConstantSDNode *SubIdx = dyn_cast<ConstantSDNode>(Op.getOperand(1));
     unsigned NumSrcElts = Src.getValueType().getVectorNumElements();
+    APInt DemandedSrc = APInt::getAllOnesValue(NumSrcElts);
     if (SubIdx && SubIdx->getAPIntValue().ule(NumSrcElts - NumElts)) {
       // Offset the demanded elts by the subvector index.
       uint64_t Idx = SubIdx->getZExtValue();
-      APInt DemandedSrc = DemandedElts.zextOrSelf(NumSrcElts).shl(Idx);
-      Known = computeKnownBits(Src, DemandedSrc, Depth + 1);
-    } else {
-      Known = computeKnownBits(Src, Depth + 1);
+      DemandedSrc = DemandedElts.zextOrSelf(NumSrcElts).shl(Idx);
     }
+    Known = computeKnownBits(Src, DemandedSrc, Depth + 1);
     break;
   }
   case ISD::SCALAR_TO_VECTOR: {
@@ -3814,13 +3813,13 @@ unsigned SelectionDAG::ComputeNumSignBits(SDValue Op, const APInt &DemandedElts,
     SDValue Src = Op.getOperand(0);
     ConstantSDNode *SubIdx = dyn_cast<ConstantSDNode>(Op.getOperand(1));
     unsigned NumSrcElts = Src.getValueType().getVectorNumElements();
+    APInt DemandedSrc = APInt::getAllOnesValue(NumSrcElts);
     if (SubIdx && SubIdx->getAPIntValue().ule(NumSrcElts - NumElts)) {
       // Offset the demanded elts by the subvector index.
       uint64_t Idx = SubIdx->getZExtValue();
-      APInt DemandedSrc = DemandedElts.zextOrSelf(NumSrcElts).shl(Idx);
-      return ComputeNumSignBits(Src, DemandedSrc, Depth + 1);
+      DemandedSrc = DemandedElts.zextOrSelf(NumSrcElts).shl(Idx);
     }
-    return ComputeNumSignBits(Src, Depth + 1);
+    return ComputeNumSignBits(Src, DemandedSrc, Depth + 1);
   }
   case ISD::CONCAT_VECTORS: {
     // Determine the minimum number of sign bits across all demanded