Index: llvm/lib/CodeGen/SelectionDAG/LegalizeFloatTypes.cpp
===================================================================
--- llvm/lib/CodeGen/SelectionDAG/LegalizeFloatTypes.cpp
+++ llvm/lib/CodeGen/SelectionDAG/LegalizeFloatTypes.cpp
@@ -61,6 +61,7 @@
 #endif
     llvm_unreachable("Do not know how to soften the result of this operator!");
 
+    case ISD::ARITH_FENCE: R = SoftenFloatRes_ARITH_FENCE(N); break;
     case ISD::MERGE_VALUES:R = SoftenFloatRes_MERGE_VALUES(N, ResNo); break;
     case ISD::BITCAST:     R = SoftenFloatRes_BITCAST(N); break;
     case ISD::BUILD_PAIR:  R = SoftenFloatRes_BUILD_PAIR(N); break;
@@ -206,6 +207,20 @@
                      GetSoftenedFloat(N->getOperand(0)));
 }
 
+SDValue DAGTypeLegalizer::SoftenFloatRes_ARITH_FENCE(SDNode *N) {
+  SDLoc dl(N);
+  SDValue Op = N->getOperand(0);
+  SDValue LHS = BitConvertToInteger(Op);
+  EVT ILVT = LHS.getValueType();
+  EVT NVT = TLI.getTypeToTransformTo(*DAG.getContext(), Op.getValueType());
+  assert(ILVT == NVT && "Wrong type!");
+
+  SDValue NewFence = DAG.getNode(ISD::ARITH_FENCE, dl, ILVT, LHS);
+  ReplaceValueWith(SDValue(N, 0), NewFence);
+
+  return NewFence;
+}
+
 SDValue DAGTypeLegalizer::SoftenFloatRes_MERGE_VALUES(SDNode *N,
                                                       unsigned ResNo) {
   SDValue Op = DisintegrateMERGE_VALUES(N, ResNo);
Index: llvm/lib/CodeGen/SelectionDAG/LegalizeIntegerTypes.cpp
===================================================================
--- llvm/lib/CodeGen/SelectionDAG/LegalizeIntegerTypes.cpp
+++ llvm/lib/CodeGen/SelectionDAG/LegalizeIntegerTypes.cpp
@@ -2218,6 +2218,7 @@
     report_fatal_error("Do not know how to expand the result of this "
                        "operator!");
 
+  case ISD::ARITH_FENCE:  SplitRes_ARITH_FENCE(N, Lo, Hi); break;
   case ISD::MERGE_VALUES: SplitRes_MERGE_VALUES(N, ResNo, Lo, Hi); break;
   case ISD::SELECT:       SplitRes_SELECT(N, Lo, Hi); break;
   case ISD::SELECT_CC:    SplitRes_SELECT_CC(N, Lo, Hi); break;
Index: llvm/lib/CodeGen/SelectionDAG/LegalizeTypes.h
===================================================================
--- llvm/lib/CodeGen/SelectionDAG/LegalizeTypes.h
+++ llvm/lib/CodeGen/SelectionDAG/LegalizeTypes.h
@@ -526,6 +526,7 @@
   SDValue SoftenFloatRes_Unary(SDNode *N, RTLIB::Libcall LC);
   SDValue SoftenFloatRes_Binary(SDNode *N, RTLIB::Libcall LC);
   SDValue SoftenFloatRes_MERGE_VALUES(SDNode *N, unsigned ResNo);
+  SDValue SoftenFloatRes_ARITH_FENCE(SDNode *N);
   SDValue SoftenFloatRes_BITCAST(SDNode *N);
   SDValue SoftenFloatRes_BUILD_PAIR(SDNode *N);
   SDValue SoftenFloatRes_ConstantFP(SDNode *N);
@@ -1019,6 +1020,7 @@
   // Generic Result Splitting.
   void SplitRes_MERGE_VALUES(SDNode *N, unsigned ResNo,
                              SDValue &Lo, SDValue &Hi);
+  void SplitRes_ARITH_FENCE (SDNode *N, SDValue &Lo, SDValue &Hi);
   void SplitRes_SELECT      (SDNode *N, SDValue &Lo, SDValue &Hi);
   void SplitRes_SELECT_CC   (SDNode *N, SDValue &Lo, SDValue &Hi);
   void SplitRes_UNDEF       (SDNode *N, SDValue &Lo, SDValue &Hi);
Index: llvm/lib/CodeGen/SelectionDAG/LegalizeTypesGeneric.cpp
===================================================================
--- llvm/lib/CodeGen/SelectionDAG/LegalizeTypesGeneric.cpp
+++ llvm/lib/CodeGen/SelectionDAG/LegalizeTypesGeneric.cpp
@@ -571,3 +571,12 @@
   Lo = DAG.getNode(ISD::FREEZE, dl, L.getValueType(), L);
   Hi = DAG.getNode(ISD::FREEZE, dl, H.getValueType(), H);
 }
+
+void DAGTypeLegalizer::SplitRes_ARITH_FENCE(SDNode *N, SDValue &Lo, SDValue &Hi) {
+  SDValue L, H;
+  SDLoc dl(N);
+  GetSplitOp(N->getOperand(0), L, H);
+
+  Lo = DAG.getNode(ISD::ARITH_FENCE, dl, L.getValueType(), L);
+  Hi = DAG.getNode(ISD::ARITH_FENCE, dl, H.getValueType(), H);
+}
Index: llvm/test/CodeGen/X86/arithmetic_fence.ll
===================================================================
--- llvm/test/CodeGen/X86/arithmetic_fence.ll
+++ llvm/test/CodeGen/X86/arithmetic_fence.ll
@@ -156,6 +156,58 @@
   ret <2 x float> %3
 }
 
+; This @f7 IR test can be generated from flowing c test:
+;
+; typedef __float128 TYPE;
+; TYPE foo(TYPE *qr) {
+;   TYPE re =__arithmetic_fence(*qr);
+;   return re;
+;}
+;
+; with flowing build command:
+; clang -cc1  -triple i386-pc-linux-gnu -mreassociate  t.c -emit-llvm -O2
+
+define dso_local fp128 @foo(fp128* nocapture readonly %qr) local_unnamed_addr{
+; X86-LABEL: foo:
+; X86:       # %bb.0: # %entry
+; X86-NEXT:    pushl %edi
+; X86-NEXT:    .cfi_def_cfa_offset 8
+; X86-NEXT:    pushl %esi
+; X86-NEXT:    .cfi_def_cfa_offset 12
+; X86-NEXT:    .cfi_offset %esi, -12
+; X86-NEXT:    .cfi_offset %edi, -8
+; X86-NEXT:    movl {{[0-9]+}}(%esp), %eax
+; X86-NEXT:    movl {{[0-9]+}}(%esp), %ecx
+; X86-NEXT:    movl 12(%ecx), %edx
+; X86-NEXT:    movl 8(%ecx), %esi
+; X86-NEXT:    movl (%ecx), %edi
+; X86-NEXT:    movl 4(%ecx), %ecx
+; X86-NEXT:    #ARITH_FENCE
+; X86-NEXT:    #ARITH_FENCE
+; X86-NEXT:    #ARITH_FENCE
+; X86-NEXT:    #ARITH_FENCE
+; X86-NEXT:    movl %edx, 12(%eax)
+; X86-NEXT:    movl %esi, 8(%eax)
+; X86-NEXT:    movl %ecx, 4(%eax)
+; X86-NEXT:    movl %edi, (%eax)
+; X86-NEXT:    popl %esi
+; X86-NEXT:    .cfi_def_cfa_offset 8
+; X86-NEXT:    popl %edi
+; X86-NEXT:    .cfi_def_cfa_offset 4
+; X86-NEXT:    retl $4
+;
+; X64-LABEL: foo:
+; X64:       # %bb.0: # %entry
+; X64-NEXT:    vmovaps (%rdi), %xmm0
+; X64-NEXT:    #ARITH_FENCE
+; X64-NEXT:    retq
+entry:
+  %0 = load fp128, fp128* %qr, align 16
+  %1 = tail call reassoc fp128 @llvm.arithmetic.fence.f128(fp128 %0)
+  ret fp128 %1
+}
+
+declare fp128 @llvm.arithmetic.fence.f128(fp128)
 declare float @llvm.arithmetic.fence.f32(float)
 declare double @llvm.arithmetic.fence.f64(double)
 declare <2 x float> @llvm.arithmetic.fence.v2f32(<2 x float>)