diff --git a/compiler/x/amd64/codegen/RealRegisterMaskEnum.hpp b/compiler/x/amd64/codegen/RealRegisterMaskEnum.hpp
index bd0b1b665e..3cacb60015 100644
--- a/compiler/x/amd64/codegen/RealRegisterMaskEnum.hpp
+++ b/compiler/x/amd64/codegen/RealRegisterMaskEnum.hpp
@@ -55,20 +55,20 @@
 
    // XMMR
    //
-   xmm0Mask          = 0x00000001 << XMMRMaskOffset,
-   xmm1Mask          = 0x00000002 << XMMRMaskOffset,
-   xmm2Mask          = 0x00000004 << XMMRMaskOffset,
-   xmm3Mask          = 0x00000008 << XMMRMaskOffset,
-   xmm4Mask          = 0x00000010 << XMMRMaskOffset,
-   xmm5Mask          = 0x00000020 << XMMRMaskOffset,
-   xmm6Mask          = 0x00000040 << XMMRMaskOffset,
-   xmm7Mask          = 0x00000080 << XMMRMaskOffset,
-   xmm8Mask          = 0x00000100 << XMMRMaskOffset,
-   xmm9Mask          = 0x00000200 << XMMRMaskOffset,
-   xmm10Mask         = 0x00000400 << XMMRMaskOffset,
-   xmm11Mask         = 0x00000800 << XMMRMaskOffset,
-   xmm12Mask         = 0x00001000 << XMMRMaskOffset,
-   xmm13Mask         = 0x00002000 << XMMRMaskOffset,
-   xmm14Mask         = 0x00004000 << XMMRMaskOffset,
-   xmm15Mask         = 0x00008000 << XMMRMaskOffset,
-   AvailableXMMRMask = 0x0000FFFF << XMMRMaskOffset,
+   xmm0Mask          = 0x00000001,
+   xmm1Mask          = 0x00000002,
+   xmm2Mask          = 0x00000004,
+   xmm3Mask          = 0x00000008,
+   xmm4Mask          = 0x00000010,
+   xmm5Mask          = 0x00000020,
+   xmm6Mask          = 0x00000040,
+   xmm7Mask          = 0x00000080,
+   xmm8Mask          = 0x00000100,
+   xmm9Mask          = 0x00000200,
+   xmm10Mask         = 0x00000400,
+   xmm11Mask         = 0x00000800,
+   xmm12Mask         = 0x00001000,
+   xmm13Mask         = 0x00002000,
+   xmm14Mask         = 0x00004000,
+   xmm15Mask         = 0x00008000,
+   AvailableXMMRMask = 0x0000FFFF,
diff --git a/compiler/x/codegen/OMRCodeGenerator.cpp b/compiler/x/codegen/OMRCodeGenerator.cpp
index f78a3a3ea0..0ee4d0f178 100644
--- a/compiler/x/codegen/OMRCodeGenerator.cpp
+++ b/compiler/x/codegen/OMRCodeGenerator.cpp
@@ -1209,6 +1209,10 @@ void OMR::X86::CodeGenerator::saveBetterSpillPlacements(TR::Instruction * branch
 
 void OMR::X86::CodeGenerator::removeBetterSpillPlacementCandidate(TR::RealRegister * realReg)
    {
+   // This mechanism only supports GPR's due to interference between GPR and vector register masks
+   if (realReg->getKind() != TR_GPR)
+      return;
+
    // Remove the given real register as a candidate for better spill placement
    // of any virtual registers.
    //
@@ -1250,6 +1254,11 @@ OMR::X86::CodeGenerator::findBetterSpillPlacement(
    {
    TR::Instruction          * placement;
    TR_BetterSpillPlacement * info;
+
+   // This mechanism only supports GPR's due to interference between GPR and vector register masks
+   if (virtReg->getKind() != TR_GPR)
+      return NULL;
+
    for (info = _betterSpillPlacements; info; info = info->_next)
       {
       if (info->_virtReg == virtReg)
diff --git a/compiler/x/i386/codegen/RealRegisterMaskEnum.hpp b/compiler/x/i386/codegen/RealRegisterMaskEnum.hpp
index 105ed54cbb..e50784bbfa 100644
--- a/compiler/x/i386/codegen/RealRegisterMaskEnum.hpp
+++ b/compiler/x/i386/codegen/RealRegisterMaskEnum.hpp
@@ -47,12 +47,12 @@
 
    // XMMR
    //
-   xmm0Mask          = 0x00000001 << XMMRMaskOffset,
-   xmm1Mask          = 0x00000002 << XMMRMaskOffset,
-   xmm2Mask          = 0x00000004 << XMMRMaskOffset,
-   xmm3Mask          = 0x00000008 << XMMRMaskOffset,
-   xmm4Mask          = 0x00000010 << XMMRMaskOffset,
-   xmm5Mask          = 0x00000020 << XMMRMaskOffset,
-   xmm6Mask          = 0x00000040 << XMMRMaskOffset,
-   xmm7Mask          = 0x00000080 << XMMRMaskOffset,
-   AvailableXMMRMask = 0x000000FF << XMMRMaskOffset,
+   xmm0Mask          = 0x00000001,
+   xmm1Mask          = 0x00000002,
+   xmm2Mask          = 0x00000004,
+   xmm3Mask          = 0x00000008,
+   xmm4Mask          = 0x00000010,
+   xmm5Mask          = 0x00000020,
+   xmm6Mask          = 0x00000040,
+   xmm7Mask          = 0x00000080,
+   AvailableXMMRMask = 0x000000FF,