diff --git a/llvm/lib/CodeGen/AtomicExpandPass.cpp b/llvm/lib/CodeGen/AtomicExpandPass.cpp
--- a/llvm/lib/CodeGen/AtomicExpandPass.cpp
+++ b/llvm/lib/CodeGen/AtomicExpandPass.cpp
@@ -704,7 +704,7 @@
     PMV.AlignedAddr = Addr;
     PMV.AlignedAddrAlignment = AddrAlign;
     PMV.ShiftAmt = ConstantInt::get(PMV.ValueType, 0);
-    PMV.Mask = ConstantInt::get(PMV.ValueType, ~0);
+    PMV.Mask = ConstantInt::get(PMV.ValueType, ~0, /*isSigned*/ true);
     return PMV;
   }
 
diff --git a/llvm/test/CodeGen/PowerPC/atomics-i128.ll b/llvm/test/CodeGen/PowerPC/atomics-i128.ll
--- a/llvm/test/CodeGen/PowerPC/atomics-i128.ll
+++ b/llvm/test/CodeGen/PowerPC/atomics-i128.ll
@@ -473,8 +473,9 @@
 ; CHECK-NEXT:    stqcx. r8, 0, r3
 ; CHECK-NEXT:  .LBB11_4: # %entry
 ; CHECK-NEXT:    lwsync
-; CHECK-NEXT:    xor r3, r5, r9
-; CHECK-NEXT:    or r3, r3, r4
+; CHECK-NEXT:    xor r3, r4, r8
+; CHECK-NEXT:    xor r4, r5, r9
+; CHECK-NEXT:    or r3, r4, r3
 ; CHECK-NEXT:    cntlzd r3, r3
 ; CHECK-NEXT:    rldicl r3, r3, 58, 63
 ; CHECK-NEXT:    blr
diff --git a/llvm/test/Transforms/AtomicExpand/PowerPC/cmpxchg.ll b/llvm/test/Transforms/AtomicExpand/PowerPC/cmpxchg.ll
--- a/llvm/test/Transforms/AtomicExpand/PowerPC/cmpxchg.ll
+++ b/llvm/test/Transforms/AtomicExpand/PowerPC/cmpxchg.ll
@@ -24,7 +24,7 @@
 ; CHECK-NEXT:    [[TMP4:%.*]] = shl i128 [[HI64]], 64
 ; CHECK-NEXT:    [[VAL64:%.*]] = or i128 [[LO64]], [[TMP4]]
 ; CHECK-NEXT:    [[TMP5:%.*]] = insertvalue { i128, i1 } undef, i128 [[VAL64]], 0
-; CHECK-NEXT:    [[TMP6:%.*]] = and i128 [[VAL64]], 18446744073709551615
+; CHECK-NEXT:    [[TMP6:%.*]] = and i128 [[VAL64]], -1
 ; CHECK-NEXT:    [[SUCCESS:%.*]] = icmp eq i128 [[CMPVAL_SHIFTED]], [[TMP6]]
 ; CHECK-NEXT:    [[TMP7:%.*]] = insertvalue { i128, i1 } [[TMP5]], i1 [[SUCCESS]], 1
 ; CHECK-NEXT:    [[SUCC:%.*]] = extractvalue { i128, i1 } [[TMP7]], 1