Index: lldb/trunk/source/Plugins/Process/Linux/NativeRegisterContextLinux_x86_64.cpp
===================================================================
--- lldb/trunk/source/Plugins/Process/Linux/NativeRegisterContextLinux_x86_64.cpp
+++ lldb/trunk/source/Plugins/Process/Linux/NativeRegisterContextLinux_x86_64.cpp
@@ -903,26 +903,13 @@
     return false;
 
   if (byte_order == lldb::eByteOrderLittle) {
-    ::memcpy(m_ymm_set.ymm[reg_index - m_reg_info.first_ymm].bytes,
-             m_xstate->fxsave.xmm[reg_index - m_reg_info.first_ymm].bytes,
-             sizeof(XMMReg));
-    ::memcpy(m_ymm_set.ymm[reg_index - m_reg_info.first_ymm].bytes +
-                 sizeof(XMMReg),
-             m_xstate->xsave.ymmh[reg_index - m_reg_info.first_ymm].bytes,
-             sizeof(YMMHReg));
+    uint32_t reg_no = reg_index - m_reg_info.first_ymm;
+    m_ymm_set.ymm[reg_no] = XStateToYMM(
+        m_xstate->fxsave.xmm[reg_no].bytes,
+        m_xstate->xsave.ymmh[reg_no].bytes);
     return true;
   }
 
-  if (byte_order == lldb::eByteOrderBig) {
-    ::memcpy(m_ymm_set.ymm[reg_index - m_reg_info.first_ymm].bytes +
-                 sizeof(XMMReg),
-             m_xstate->fxsave.xmm[reg_index - m_reg_info.first_ymm].bytes,
-             sizeof(XMMReg));
-    ::memcpy(m_ymm_set.ymm[reg_index - m_reg_info.first_ymm].bytes,
-             m_xstate->xsave.ymmh[reg_index - m_reg_info.first_ymm].bytes,
-             sizeof(YMMHReg));
-    return true;
-  }
   return false; // unsupported or invalid byte order
 }
 
@@ -932,22 +919,13 @@
     return false;
 
   if (byte_order == lldb::eByteOrderLittle) {
-    ::memcpy(m_xstate->fxsave.xmm[reg - m_reg_info.first_ymm].bytes,
-             m_ymm_set.ymm[reg - m_reg_info.first_ymm].bytes, sizeof(XMMReg));
-    ::memcpy(m_xstate->xsave.ymmh[reg - m_reg_info.first_ymm].bytes,
-             m_ymm_set.ymm[reg - m_reg_info.first_ymm].bytes + sizeof(XMMReg),
-             sizeof(YMMHReg));
+    uint32_t reg_no = reg - m_reg_info.first_ymm;
+    YMMToXState(m_ymm_set.ymm[reg_no],
+        m_xstate->fxsave.xmm[reg_no].bytes,
+        m_xstate->xsave.ymmh[reg_no].bytes);
     return true;
   }
 
-  if (byte_order == lldb::eByteOrderBig) {
-    ::memcpy(m_xstate->fxsave.xmm[reg - m_reg_info.first_ymm].bytes,
-             m_ymm_set.ymm[reg - m_reg_info.first_ymm].bytes + sizeof(XMMReg),
-             sizeof(XMMReg));
-    ::memcpy(m_xstate->xsave.ymmh[reg - m_reg_info.first_ymm].bytes,
-             m_ymm_set.ymm[reg - m_reg_info.first_ymm].bytes, sizeof(YMMHReg));
-    return true;
-  }
   return false; // unsupported or invalid byte order
 }
 
Index: lldb/trunk/source/Plugins/Process/Utility/RegisterContextPOSIX_x86.cpp
===================================================================
--- lldb/trunk/source/Plugins/Process/Utility/RegisterContextPOSIX_x86.cpp
+++ lldb/trunk/source/Plugins/Process/Utility/RegisterContextPOSIX_x86.cpp
@@ -474,22 +474,13 @@
     return false;
 
   if (byte_order == eByteOrderLittle) {
-    ::memcpy(m_fpr.fxsave.xmm[reg - m_reg_info.first_ymm].bytes,
-             m_ymm_set.ymm[reg - m_reg_info.first_ymm].bytes, sizeof(XMMReg));
-    ::memcpy(m_fpr.xsave.ymmh[reg - m_reg_info.first_ymm].bytes,
-             m_ymm_set.ymm[reg - m_reg_info.first_ymm].bytes + sizeof(XMMReg),
-             sizeof(YMMHReg));
+    uint32_t reg_no = reg - m_reg_info.first_ymm;
+    YMMToXState(m_ymm_set.ymm[reg_no],
+        m_fpr.fxsave.xmm[reg_no].bytes,
+        m_fpr.xsave.ymmh[reg_no].bytes);
     return true;
   }
 
-  if (byte_order == eByteOrderBig) {
-    ::memcpy(m_fpr.fxsave.xmm[reg - m_reg_info.first_ymm].bytes,
-             m_ymm_set.ymm[reg - m_reg_info.first_ymm].bytes + sizeof(XMMReg),
-             sizeof(XMMReg));
-    ::memcpy(m_fpr.xsave.ymmh[reg - m_reg_info.first_ymm].bytes,
-             m_ymm_set.ymm[reg - m_reg_info.first_ymm].bytes, sizeof(YMMHReg));
-    return true;
-  }
   return false; // unsupported or invalid byte order
 }
 
@@ -500,24 +491,13 @@
     return false;
 
   if (byte_order == eByteOrderLittle) {
-    ::memcpy(m_ymm_set.ymm[reg - m_reg_info.first_ymm].bytes,
-             m_fpr.fxsave.xmm[reg - m_reg_info.first_ymm].bytes,
-             sizeof(XMMReg));
-    ::memcpy(m_ymm_set.ymm[reg - m_reg_info.first_ymm].bytes + sizeof(XMMReg),
-             m_fpr.xsave.ymmh[reg - m_reg_info.first_ymm].bytes,
-             sizeof(YMMHReg));
+    uint32_t reg_no = reg - m_reg_info.first_ymm;
+    m_ymm_set.ymm[reg_no] = XStateToYMM(
+        m_fpr.fxsave.xmm[reg_no].bytes,
+        m_fpr.xsave.ymmh[reg_no].bytes);
     return true;
   }
 
-  if (byte_order == eByteOrderBig) {
-    ::memcpy(m_ymm_set.ymm[reg - m_reg_info.first_ymm].bytes + sizeof(XMMReg),
-             m_fpr.fxsave.xmm[reg - m_reg_info.first_ymm].bytes,
-             sizeof(XMMReg));
-    ::memcpy(m_ymm_set.ymm[reg - m_reg_info.first_ymm].bytes,
-             m_fpr.xsave.ymmh[reg - m_reg_info.first_ymm].bytes,
-             sizeof(YMMHReg));
-    return true;
-  }
   return false; // unsupported or invalid byte order
 }
 
Index: lldb/trunk/source/Plugins/Process/Utility/RegisterContext_x86.h
===================================================================
--- lldb/trunk/source/Plugins/Process/Utility/RegisterContext_x86.h
+++ lldb/trunk/source/Plugins/Process/Utility/RegisterContext_x86.h
@@ -353,6 +353,22 @@
 
 LLVM_ENABLE_BITMASK_ENUMS_IN_NAMESPACE();
 
+// Convenience function to combine YMM register data from XSAVE-style input.
+inline YMMReg XStateToYMM(const void* xmm_bytes, const void* ymmh_bytes) {
+  YMMReg ret;
+
+  ::memcpy(ret.bytes, xmm_bytes, sizeof(XMMReg));
+  ::memcpy(ret.bytes + sizeof(XMMReg), ymmh_bytes, sizeof(YMMHReg));
+
+  return ret;
+}
+
+// Convenience function to copy YMM register data into XSAVE-style output.
+inline void YMMToXState(const YMMReg& input, void* xmm_bytes, void* ymmh_bytes) {
+  ::memcpy(xmm_bytes, input.bytes, sizeof(XMMReg));
+  ::memcpy(ymmh_bytes, input.bytes + sizeof(XMMReg), sizeof(YMMHReg));
+}
+
 } // namespace lldb_private
 
 #endif