diff --git a/llvm/utils/TableGen/CodeGenRegisters.cpp b/llvm/utils/TableGen/CodeGenRegisters.cpp
index d1abdb74ea4a9..b9d404aaee5fd 100644
--- a/llvm/utils/TableGen/CodeGenRegisters.cpp
+++ b/llvm/utils/TableGen/CodeGenRegisters.cpp
@@ -2144,7 +2144,7 @@ void CodeGenRegBank::computeRegUnitLaneMasks() {
     // Create an initial lane mask for all register units.
     const auto &RegUnits = Register.getRegUnits();
     CodeGenRegister::RegUnitLaneMaskList RegUnitLaneMasks(
-        RegUnits.count(), LaneBitmask::getAll());
+        RegUnits.count(), LaneBitmask::getNone());
     // Iterate through SubRegisters.
     typedef CodeGenRegister::SubRegMap SubRegMap;
     const SubRegMap &SubRegs = Register.getSubRegs();
@@ -2163,7 +2163,7 @@ void CodeGenRegBank::computeRegUnitLaneMasks() {
         unsigned u = 0;
         for (unsigned RU : RegUnits) {
           if (SUI == RU) {
-            RegUnitLaneMasks[u] &= LaneMask;
+            RegUnitLaneMasks[u] |= LaneMask;
             assert(!Found);
             Found = true;
           }
@@ -2173,6 +2173,10 @@ void CodeGenRegBank::computeRegUnitLaneMasks() {
         assert(Found);
       }
     }
+    for (auto &Mask : RegUnitLaneMasks) {
+      if (Mask.none())
+        Mask = LaneBitmask::getAll();
+    }
     Register.setRegUnitLaneMasks(RegUnitLaneMasks);
   }
 }