foo

llvm-svn: 299618

llvm/lib/CodeGen/SelectionDAG/TargetLowering.cpp

@@ -791,6 +791,9 @@ bool TargetLowering::SimplifyDemandedBits(SDValue Op,
       // TODO: Should we check for other forms of sign-bit comparisons?
       // Examples: X <= -1, X >= 0
     }
+    if (getBooleanContents(Op.getOperand(0).getValueType()) ==
+            BooleanContent::ZeroOrOneBooleanContent && BitWidth > 1)
+      KnownZero.setBitsFrom(1);
     break;
   }
   case ISD::SHL: