Index: lib/CodeGen/SelectionDAG/TargetLowering.cpp
===================================================================
--- lib/CodeGen/SelectionDAG/TargetLowering.cpp
+++ lib/CodeGen/SelectionDAG/TargetLowering.cpp
@@ -1220,6 +1220,12 @@
                                                  Sign, ShAmt));
       }
     }
+    // If this is a bitcast of a constant, let computeKnownBits handle it.  Only
+    // do this on a recursive call where Known may be useful to the caller.
+    if (Depth > 0 && isConstOrConstSplat(Op.getOperand(0))) {
+      TLO.DAG.computeKnownBits(Op, Known, Depth);
+      return false;
+    }
     break;
   case ISD::ADD:
   case ISD::MUL:
Index: test/CodeGen/X86/combine-and.ll
===================================================================
--- test/CodeGen/X86/combine-and.ll
+++ test/CodeGen/X86/combine-and.ll
@@ -281,7 +281,6 @@
 ; CHECK:       # %bb.0:
 ; CHECK-NEXT:    psrlw $1, %xmm0
 ; CHECK-NEXT:    pand {{.*}}(%rip), %xmm0
-; CHECK-NEXT:    pand {{.*}}(%rip), %xmm0
 ; CHECK-NEXT:    paddb %xmm1, %xmm0
 ; CHECK-NEXT:    retq
   %1 = lshr <16 x i8> %a0, <i8 1, i8 1, i8 1, i8 1, i8 1, i8 1, i8 1, i8 1, i8 1, i8 1, i8 1, i8 1, i8 1, i8 1, i8 1, i8 1>