diff --git a/llvm/lib/Target/X86/X86ISelLowering.h b/llvm/lib/Target/X86/X86ISelLowering.h
--- a/llvm/lib/Target/X86/X86ISelLowering.h
+++ b/llvm/lib/Target/X86/X86ISelLowering.h
@@ -1561,6 +1561,9 @@
     SDValue LowerFLT_ROUNDS_(SDValue Op, SelectionDAG &DAG) const;
     SDValue LowerSET_ROUNDING(SDValue Op, SelectionDAG &DAG) const;
     SDValue LowerWin64_i128OP(SDValue Op, SelectionDAG &DAG) const;
+    SDValue LowerWin64_FP_TO_INT128(SDValue Op, SelectionDAG &DAG,
+                                    SDValue &Chain) const;
+    SDValue LowerWin64_INT128_TO_FP(SDValue Op, SelectionDAG &DAG) const;
     SDValue LowerGC_TRANSITION(SDValue Op, SelectionDAG &DAG) const;
     SDValue LowerINTRINSIC_WO_CHAIN(SDValue Op, SelectionDAG &DAG) const;
     SDValue lowerFaddFsub(SDValue Op, SelectionDAG &DAG) const;
diff --git a/llvm/lib/Target/X86/X86ISelLowering.cpp b/llvm/lib/Target/X86/X86ISelLowering.cpp
--- a/llvm/lib/Target/X86/X86ISelLowering.cpp
+++ b/llvm/lib/Target/X86/X86ISelLowering.cpp
@@ -2166,6 +2166,14 @@
     setOperationAction(ISD::UDIV, MVT::i128, Custom);
     setOperationAction(ISD::SREM, MVT::i128, Custom);
     setOperationAction(ISD::UREM, MVT::i128, Custom);
+    setOperationAction(ISD::FP_TO_SINT, MVT::i128, Custom);
+    setOperationAction(ISD::FP_TO_UINT, MVT::i128, Custom);
+    setOperationAction(ISD::SINT_TO_FP, MVT::i128, Custom);
+    setOperationAction(ISD::UINT_TO_FP, MVT::i128, Custom);
+    setOperationAction(ISD::STRICT_FP_TO_SINT, MVT::i128, Custom);
+    setOperationAction(ISD::STRICT_FP_TO_UINT, MVT::i128, Custom);
+    setOperationAction(ISD::STRICT_SINT_TO_FP, MVT::i128, Custom);
+    setOperationAction(ISD::STRICT_UINT_TO_FP, MVT::i128, Custom);
   }
 
   // On 32 bit MSVC, `fmodf(f32)` is not defined - only `fmod(f64)`
@@ -20393,6 +20401,9 @@
   MVT VT = Op.getSimpleValueType();
   SDLoc dl(Op);
 
+  if (Subtarget.isTargetWin64() && SrcVT == MVT::i128)
+    return LowerWin64_INT128_TO_FP(Op, DAG);
+
   if (SDValue Extract = vectorizeExtractedCast(Op, DAG, Subtarget))
     return Extract;
 
@@ -20892,6 +20903,9 @@
   if (DstVT.isVector())
     return lowerUINT_TO_FP_vec(Op, DAG, Subtarget);
 
+  if (Subtarget.isTargetWin64() && SrcVT == MVT::i128)
+    return LowerWin64_INT128_TO_FP(Op, DAG);
+
   if (SDValue Extract = vectorizeExtractedCast(Op, DAG, Subtarget))
     return Extract;
 
@@ -28624,6 +28638,77 @@
   return DAG.getBitcast(VT, CallInfo.first);
 }
 
+SDValue X86TargetLowering::LowerWin64_FP_TO_INT128(SDValue Op,
+                                                   SelectionDAG &DAG,
+                                                   SDValue &Chain) const {
+  assert(Subtarget.isTargetWin64() && "Unexpected target");
+  EVT VT = Op.getValueType();
+  bool IsStrict = Op->isStrictFPOpcode();
+
+  SDValue Arg = Op.getOperand(IsStrict ? 1 : 0);
+  EVT ArgVT = Arg.getValueType();
+
+  assert(VT.isInteger() && VT.getSizeInBits() == 128 &&
+         "Unexpected return type for lowering");
+
+  RTLIB::Libcall LC;
+  if (Op->getOpcode() == ISD::FP_TO_SINT ||
+      Op->getOpcode() == ISD::STRICT_FP_TO_SINT)
+    LC = RTLIB::getFPTOSINT(ArgVT, VT);
+  else
+    LC = RTLIB::getFPTOUINT(ArgVT, VT);
+  assert(LC != RTLIB::UNKNOWN_LIBCALL && "Unexpected request for libcall!");
+
+  SDLoc dl(Op);
+  MakeLibCallOptions CallOptions;
+  Chain = IsStrict ? Op.getOperand(0) : DAG.getEntryNode();
+
+  SDValue Result;
+  // Expect the i128 argument returned as a v2i64 in xmm0, cast back to the
+  // expected VT (i128).
+  std::tie(Result, Chain) =
+      makeLibCall(DAG, LC, MVT::v2i64, Arg, CallOptions, dl, Chain);
+  Result = DAG.getBitcast(VT, Result);
+  return Result;
+}
+
+SDValue X86TargetLowering::LowerWin64_INT128_TO_FP(SDValue Op,
+                                                   SelectionDAG &DAG) const {
+  assert(Subtarget.isTargetWin64() && "Unexpected target");
+  EVT VT = Op.getValueType();
+  bool IsStrict = Op->isStrictFPOpcode();
+
+  SDValue Arg = Op.getOperand(IsStrict ? 1 : 0);
+  EVT ArgVT = Arg.getValueType();
+
+  assert(ArgVT.isInteger() && ArgVT.getSizeInBits() == 128 &&
+         "Unexpected argument type for lowering");
+
+  RTLIB::Libcall LC;
+  if (Op->getOpcode() == ISD::SINT_TO_FP ||
+      Op->getOpcode() == ISD::STRICT_SINT_TO_FP)
+    LC = RTLIB::getSINTTOFP(ArgVT, VT);
+  else
+    LC = RTLIB::getUINTTOFP(ArgVT, VT);
+  assert(LC != RTLIB::UNKNOWN_LIBCALL && "Unexpected request for libcall!");
+
+  SDLoc dl(Op);
+  MakeLibCallOptions CallOptions;
+  SDValue Chain = IsStrict ? Op.getOperand(0) : DAG.getEntryNode();
+
+  // Pass the i128 argument as an indirect argument on the stack.
+  SDValue StackPtr = DAG.CreateStackTemporary(ArgVT, 16);
+  int SPFI = cast<FrameIndexSDNode>(StackPtr.getNode())->getIndex();
+  MachinePointerInfo MPI =
+      MachinePointerInfo::getFixedStack(DAG.getMachineFunction(), SPFI);
+  Chain = DAG.getStore(Chain, dl, Arg, StackPtr, MPI, Align(16));
+
+  SDValue Result;
+  std::tie(Result, Chain) =
+      makeLibCall(DAG, LC, VT, StackPtr, CallOptions, dl, Chain);
+  return IsStrict ? DAG.getMergeValues({Result, Chain}, dl) : Result;
+}
+
 // Return true if the required (according to Opcode) shift-imm form is natively
 // supported by the Subtarget
 static bool SupportedVectorShiftWithImm(MVT VT, const X86Subtarget &Subtarget,
@@ -31602,6 +31687,15 @@
       return;
     }
 
+    if (VT == MVT::i128 && Subtarget.isTargetWin64()) {
+      SDValue Chain;
+      SDValue V = LowerWin64_FP_TO_INT128(SDValue(N, 0), DAG, Chain);
+      Results.push_back(V);
+      if (IsStrict)
+        Results.push_back(Chain);
+      return;
+    }
+
     SDValue Chain;
     if (SDValue V = FP_TO_INTHelper(SDValue(N, 0), DAG, IsSigned, Chain)) {
       Results.push_back(V);
diff --git a/llvm/test/CodeGen/X86/i128-fpconv-win64-strict.ll b/llvm/test/CodeGen/X86/i128-fpconv-win64-strict.ll
new file mode 100644
--- /dev/null
+++ b/llvm/test/CodeGen/X86/i128-fpconv-win64-strict.ll
@@ -0,0 +1,208 @@
+; NOTE: Assertions have been autogenerated by utils/update_llc_test_checks.py
+; RUN: llc < %s -mtriple=x86_64-win32 | FileCheck %s -check-prefix=WIN64
+; RUN: llc < %s -mtriple=x86_64-mingw32 | FileCheck %s -check-prefix=WIN64
+
+define i64 @double_to_i128(double %d) nounwind {
+; WIN64-LABEL: double_to_i128:
+; WIN64:       # %bb.0:
+; WIN64-NEXT:    subq $40, %rsp
+; WIN64-NEXT:    callq __fixdfti
+; WIN64-NEXT:    movq %xmm0, %rax
+; WIN64-NEXT:    addq $40, %rsp
+; WIN64-NEXT:    retq
+  %1 = tail call i128 @llvm.experimental.constrained.fptosi.i128.f64(double %d, metadata !"fpexcept.strict")
+  %2 = trunc i128 %1 to i64
+  ret i64 %2
+}
+
+define i64 @double_to_ui128(double %d) nounwind {
+; WIN64-LABEL: double_to_ui128:
+; WIN64:       # %bb.0:
+; WIN64-NEXT:    subq $40, %rsp
+; WIN64-NEXT:    callq __fixunsdfti
+; WIN64-NEXT:    movq %xmm0, %rax
+; WIN64-NEXT:    addq $40, %rsp
+; WIN64-NEXT:    retq
+  %1 = tail call i128 @llvm.experimental.constrained.fptoui.i128.f64(double %d, metadata !"fpexcept.strict")
+  %2 = trunc i128 %1 to i64
+  ret i64 %2
+}
+
+define i64 @float_to_i128(float %d) nounwind {
+; WIN64-LABEL: float_to_i128:
+; WIN64:       # %bb.0:
+; WIN64-NEXT:    subq $40, %rsp
+; WIN64-NEXT:    callq __fixsfti
+; WIN64-NEXT:    movq %xmm0, %rax
+; WIN64-NEXT:    addq $40, %rsp
+; WIN64-NEXT:    retq
+  %1 = tail call i128 @llvm.experimental.constrained.fptosi.i128.f32(float %d, metadata !"fpexcept.strict")
+  %2 = trunc i128 %1 to i64
+  ret i64 %2
+}
+
+define i64 @float_to_ui128(float %d) nounwind {
+; WIN64-LABEL: float_to_ui128:
+; WIN64:       # %bb.0:
+; WIN64-NEXT:    subq $40, %rsp
+; WIN64-NEXT:    callq __fixunssfti
+; WIN64-NEXT:    movq %xmm0, %rax
+; WIN64-NEXT:    addq $40, %rsp
+; WIN64-NEXT:    retq
+  %1 = tail call i128 @llvm.experimental.constrained.fptoui.i128.f32(float %d, metadata !"fpexcept.strict")
+  %2 = trunc i128 %1 to i64
+  ret i64 %2
+}
+
+define i64 @longdouble_to_i128(x86_fp80* nocapture readonly %0) nounwind {
+; WIN64-LABEL: longdouble_to_i128:
+; WIN64:       # %bb.0:
+; WIN64-NEXT:    subq $56, %rsp
+; WIN64-NEXT:    fldt (%rcx)
+; WIN64-NEXT:    fstpt {{[0-9]+}}(%rsp)
+; WIN64-NEXT:    leaq {{[0-9]+}}(%rsp), %rcx
+; WIN64-NEXT:    callq __fixxfti
+; WIN64-NEXT:    movq %xmm0, %rax
+; WIN64-NEXT:    addq $56, %rsp
+; WIN64-NEXT:    retq
+  %2 = load x86_fp80, x86_fp80* %0, align 16
+  %3 = tail call i128 @llvm.experimental.constrained.fptosi.i128.f80(x86_fp80 %2, metadata !"fpexcept.strict")
+  %4 = trunc i128 %3 to i64
+  ret i64 %4
+}
+
+define i64 @longdouble_to_ui128(x86_fp80* nocapture readonly %0) nounwind {
+; WIN64-LABEL: longdouble_to_ui128:
+; WIN64:       # %bb.0:
+; WIN64-NEXT:    subq $56, %rsp
+; WIN64-NEXT:    fldt (%rcx)
+; WIN64-NEXT:    fstpt {{[0-9]+}}(%rsp)
+; WIN64-NEXT:    leaq {{[0-9]+}}(%rsp), %rcx
+; WIN64-NEXT:    callq __fixunsxfti
+; WIN64-NEXT:    movq %xmm0, %rax
+; WIN64-NEXT:    addq $56, %rsp
+; WIN64-NEXT:    retq
+  %2 = load x86_fp80, x86_fp80* %0, align 16
+  %3 = tail call i128 @llvm.experimental.constrained.fptoui.i128.f80(x86_fp80 %2, metadata !"fpexcept.strict")
+  %4 = trunc i128 %3 to i64
+  ret i64 %4
+}
+
+define double @i128_to_double(i128* nocapture readonly %0) nounwind {
+; WIN64-LABEL: i128_to_double:
+; WIN64:       # %bb.0:
+; WIN64-NEXT:    subq $56, %rsp
+; WIN64-NEXT:    movaps (%rcx), %xmm0
+; WIN64-NEXT:    movaps %xmm0, {{[0-9]+}}(%rsp)
+; WIN64-NEXT:    leaq {{[0-9]+}}(%rsp), %rcx
+; WIN64-NEXT:    callq __floattidf
+; WIN64-NEXT:    addq $56, %rsp
+; WIN64-NEXT:    retq
+  %2 = load i128, i128* %0, align 16
+  %3 = tail call double @llvm.experimental.constrained.sitofp.f64.i128(i128 %2, metadata !"round.dynamic", metadata !"fpexcept.strict")
+  ret double %3
+}
+
+define double @ui128_to_double(i128* nocapture readonly %0) nounwind {
+; WIN64-LABEL: ui128_to_double:
+; WIN64:       # %bb.0:
+; WIN64-NEXT:    subq $56, %rsp
+; WIN64-NEXT:    movaps (%rcx), %xmm0
+; WIN64-NEXT:    movaps %xmm0, {{[0-9]+}}(%rsp)
+; WIN64-NEXT:    leaq {{[0-9]+}}(%rsp), %rcx
+; WIN64-NEXT:    callq __floatuntidf
+; WIN64-NEXT:    addq $56, %rsp
+; WIN64-NEXT:    retq
+  %2 = load i128, i128* %0, align 16
+  %3 = tail call double @llvm.experimental.constrained.uitofp.f64.i128(i128 %2, metadata !"round.dynamic", metadata !"fpexcept.strict")
+  ret double %3
+}
+
+define float @i128_to_float(i128* nocapture readonly %0) nounwind {
+; WIN64-LABEL: i128_to_float:
+; WIN64:       # %bb.0:
+; WIN64-NEXT:    subq $56, %rsp
+; WIN64-NEXT:    movaps (%rcx), %xmm0
+; WIN64-NEXT:    movaps %xmm0, {{[0-9]+}}(%rsp)
+; WIN64-NEXT:    leaq {{[0-9]+}}(%rsp), %rcx
+; WIN64-NEXT:    callq __floattisf
+; WIN64-NEXT:    addq $56, %rsp
+; WIN64-NEXT:    retq
+  %2 = load i128, i128* %0, align 16
+  %3 = tail call float @llvm.experimental.constrained.sitofp.f32.i128(i128 %2, metadata !"round.dynamic", metadata !"fpexcept.strict")
+  ret float %3
+}
+
+define float @ui128_to_float(i128* nocapture readonly %0) nounwind {
+; WIN64-LABEL: ui128_to_float:
+; WIN64:       # %bb.0:
+; WIN64-NEXT:    subq $56, %rsp
+; WIN64-NEXT:    movaps (%rcx), %xmm0
+; WIN64-NEXT:    movaps %xmm0, {{[0-9]+}}(%rsp)
+; WIN64-NEXT:    leaq {{[0-9]+}}(%rsp), %rcx
+; WIN64-NEXT:    callq __floatuntisf
+; WIN64-NEXT:    addq $56, %rsp
+; WIN64-NEXT:    retq
+  %2 = load i128, i128* %0, align 16
+  %3 = tail call float @llvm.experimental.constrained.uitofp.f32.i128(i128 %2, metadata !"round.dynamic", metadata !"fpexcept.strict")
+  ret float %3
+}
+
+define void @i128_to_longdouble(x86_fp80* noalias nocapture sret(x86_fp80) align 16 %agg.result, i128* nocapture readonly %0) nounwind {
+; WIN64-LABEL: i128_to_longdouble:
+; WIN64:       # %bb.0:
+; WIN64-NEXT:    pushq %rsi
+; WIN64-NEXT:    subq $64, %rsp
+; WIN64-NEXT:    movq %rcx, %rsi
+; WIN64-NEXT:    movaps (%rdx), %xmm0
+; WIN64-NEXT:    movaps %xmm0, {{[0-9]+}}(%rsp)
+; WIN64-NEXT:    leaq {{[0-9]+}}(%rsp), %rcx
+; WIN64-NEXT:    leaq {{[0-9]+}}(%rsp), %rdx
+; WIN64-NEXT:    callq __floattixf
+; WIN64-NEXT:    fldt {{[0-9]+}}(%rsp)
+; WIN64-NEXT:    fstpt (%rsi)
+; WIN64-NEXT:    movq %rsi, %rax
+; WIN64-NEXT:    addq $64, %rsp
+; WIN64-NEXT:    popq %rsi
+; WIN64-NEXT:    retq
+  %2 = load i128, i128* %0, align 16
+  %3 = tail call x86_fp80 @llvm.experimental.constrained.sitofp.f80.i128(i128 %2, metadata !"round.dynamic", metadata !"fpexcept.strict")
+  store x86_fp80 %3, x86_fp80* %agg.result, align 16
+  ret void
+}
+
+define void @ui128_to_longdouble(x86_fp80* noalias nocapture sret(x86_fp80) align 16 %agg.result, i128* nocapture readonly %0) nounwind {
+; WIN64-LABEL: ui128_to_longdouble:
+; WIN64:       # %bb.0:
+; WIN64-NEXT:    pushq %rsi
+; WIN64-NEXT:    subq $64, %rsp
+; WIN64-NEXT:    movq %rcx, %rsi
+; WIN64-NEXT:    movaps (%rdx), %xmm0
+; WIN64-NEXT:    movaps %xmm0, {{[0-9]+}}(%rsp)
+; WIN64-NEXT:    leaq {{[0-9]+}}(%rsp), %rcx
+; WIN64-NEXT:    leaq {{[0-9]+}}(%rsp), %rdx
+; WIN64-NEXT:    callq __floatuntixf
+; WIN64-NEXT:    fldt {{[0-9]+}}(%rsp)
+; WIN64-NEXT:    fstpt (%rsi)
+; WIN64-NEXT:    movq %rsi, %rax
+; WIN64-NEXT:    addq $64, %rsp
+; WIN64-NEXT:    popq %rsi
+; WIN64-NEXT:    retq
+  %2 = load i128, i128* %0, align 16
+  %3 = tail call x86_fp80 @llvm.experimental.constrained.uitofp.f80.i128(i128 %2, metadata !"round.dynamic", metadata !"fpexcept.strict")
+  store x86_fp80 %3, x86_fp80* %agg.result, align 16
+  ret void
+}
+
+declare i128 @llvm.experimental.constrained.fptosi.i128.f64(double, metadata)
+declare i128 @llvm.experimental.constrained.fptoui.i128.f64(double, metadata)
+declare i128 @llvm.experimental.constrained.fptosi.i128.f32(float, metadata)
+declare i128 @llvm.experimental.constrained.fptoui.i128.f32(float, metadata)
+declare i128 @llvm.experimental.constrained.fptosi.i128.f80(x86_fp80, metadata)
+declare i128 @llvm.experimental.constrained.fptoui.i128.f80(x86_fp80, metadata)
+declare double @llvm.experimental.constrained.sitofp.f64.i128(i128, metadata, metadata)
+declare double @llvm.experimental.constrained.uitofp.f64.i128(i128, metadata, metadata)
+declare float @llvm.experimental.constrained.sitofp.f32.i128(i128, metadata, metadata)
+declare float @llvm.experimental.constrained.uitofp.f32.i128(i128, metadata, metadata)
+declare x86_fp80 @llvm.experimental.constrained.sitofp.f80.i128(i128, metadata, metadata)
+declare x86_fp80 @llvm.experimental.constrained.uitofp.f80.i128(i128, metadata, metadata)
diff --git a/llvm/test/CodeGen/X86/i128-fpconv-win64.ll b/llvm/test/CodeGen/X86/i128-fpconv-win64.ll
new file mode 100644
--- /dev/null
+++ b/llvm/test/CodeGen/X86/i128-fpconv-win64.ll
@@ -0,0 +1,195 @@
+; NOTE: Assertions have been autogenerated by utils/update_llc_test_checks.py
+; RUN: llc < %s -mtriple=x86_64-win32 | FileCheck %s -check-prefix=WIN64
+; RUN: llc < %s -mtriple=x86_64-mingw32 | FileCheck %s -check-prefix=WIN64
+
+define i64 @double_to_i128(double %d) nounwind {
+; WIN64-LABEL: double_to_i128:
+; WIN64:       # %bb.0:
+; WIN64-NEXT:    subq $40, %rsp
+; WIN64-NEXT:    callq __fixdfti
+; WIN64-NEXT:    movq %xmm0, %rax
+; WIN64-NEXT:    addq $40, %rsp
+; WIN64-NEXT:    retq
+  %1 = fptosi double %d to i128
+  %2 = trunc i128 %1 to i64
+  ret i64 %2
+}
+
+define i64 @double_to_ui128(double %d) nounwind {
+; WIN64-LABEL: double_to_ui128:
+; WIN64:       # %bb.0:
+; WIN64-NEXT:    subq $40, %rsp
+; WIN64-NEXT:    callq __fixunsdfti
+; WIN64-NEXT:    movq %xmm0, %rax
+; WIN64-NEXT:    addq $40, %rsp
+; WIN64-NEXT:    retq
+  %1 = fptoui double %d to i128
+  %2 = trunc i128 %1 to i64
+  ret i64 %2
+}
+
+define i64 @float_to_i128(float %d) nounwind {
+; WIN64-LABEL: float_to_i128:
+; WIN64:       # %bb.0:
+; WIN64-NEXT:    subq $40, %rsp
+; WIN64-NEXT:    callq __fixsfti
+; WIN64-NEXT:    movq %xmm0, %rax
+; WIN64-NEXT:    addq $40, %rsp
+; WIN64-NEXT:    retq
+  %1 = fptosi float %d to i128
+  %2 = trunc i128 %1 to i64
+  ret i64 %2
+}
+
+define i64 @float_to_ui128(float %d) nounwind {
+; WIN64-LABEL: float_to_ui128:
+; WIN64:       # %bb.0:
+; WIN64-NEXT:    subq $40, %rsp
+; WIN64-NEXT:    callq __fixunssfti
+; WIN64-NEXT:    movq %xmm0, %rax
+; WIN64-NEXT:    addq $40, %rsp
+; WIN64-NEXT:    retq
+  %1 = fptoui float %d to i128
+  %2 = trunc i128 %1 to i64
+  ret i64 %2
+}
+
+define i64 @longdouble_to_i128(x86_fp80* nocapture readonly %0) nounwind {
+; WIN64-LABEL: longdouble_to_i128:
+; WIN64:       # %bb.0:
+; WIN64-NEXT:    subq $56, %rsp
+; WIN64-NEXT:    fldt (%rcx)
+; WIN64-NEXT:    fstpt {{[0-9]+}}(%rsp)
+; WIN64-NEXT:    leaq {{[0-9]+}}(%rsp), %rcx
+; WIN64-NEXT:    callq __fixxfti
+; WIN64-NEXT:    movq %xmm0, %rax
+; WIN64-NEXT:    addq $56, %rsp
+; WIN64-NEXT:    retq
+  %2 = load x86_fp80, x86_fp80* %0, align 16
+  %3 = fptosi x86_fp80 %2 to i128
+  %4 = trunc i128 %3 to i64
+  ret i64 %4
+}
+
+define i64 @longdouble_to_ui128(x86_fp80* nocapture readonly %0) nounwind {
+; WIN64-LABEL: longdouble_to_ui128:
+; WIN64:       # %bb.0:
+; WIN64-NEXT:    subq $56, %rsp
+; WIN64-NEXT:    fldt (%rcx)
+; WIN64-NEXT:    fstpt {{[0-9]+}}(%rsp)
+; WIN64-NEXT:    leaq {{[0-9]+}}(%rsp), %rcx
+; WIN64-NEXT:    callq __fixunsxfti
+; WIN64-NEXT:    movq %xmm0, %rax
+; WIN64-NEXT:    addq $56, %rsp
+; WIN64-NEXT:    retq
+  %2 = load x86_fp80, x86_fp80* %0, align 16
+  %3 = fptoui x86_fp80 %2 to i128
+  %4 = trunc i128 %3 to i64
+  ret i64 %4
+}
+
+define double @i128_to_double(i128* nocapture readonly %0) nounwind {
+; WIN64-LABEL: i128_to_double:
+; WIN64:       # %bb.0:
+; WIN64-NEXT:    subq $56, %rsp
+; WIN64-NEXT:    movaps (%rcx), %xmm0
+; WIN64-NEXT:    movaps %xmm0, {{[0-9]+}}(%rsp)
+; WIN64-NEXT:    leaq {{[0-9]+}}(%rsp), %rcx
+; WIN64-NEXT:    callq __floattidf
+; WIN64-NEXT:    addq $56, %rsp
+; WIN64-NEXT:    retq
+  %2 = load i128, i128* %0, align 16
+  %3 = sitofp i128 %2 to double
+  ret double %3
+}
+
+define double @ui128_to_double(i128* nocapture readonly %0) nounwind {
+; WIN64-LABEL: ui128_to_double:
+; WIN64:       # %bb.0:
+; WIN64-NEXT:    subq $56, %rsp
+; WIN64-NEXT:    movaps (%rcx), %xmm0
+; WIN64-NEXT:    movaps %xmm0, {{[0-9]+}}(%rsp)
+; WIN64-NEXT:    leaq {{[0-9]+}}(%rsp), %rcx
+; WIN64-NEXT:    callq __floatuntidf
+; WIN64-NEXT:    addq $56, %rsp
+; WIN64-NEXT:    retq
+  %2 = load i128, i128* %0, align 16
+  %3 = uitofp i128 %2 to double
+  ret double %3
+}
+
+define float @i128_to_float(i128* nocapture readonly %0) nounwind {
+; WIN64-LABEL: i128_to_float:
+; WIN64:       # %bb.0:
+; WIN64-NEXT:    subq $56, %rsp
+; WIN64-NEXT:    movaps (%rcx), %xmm0
+; WIN64-NEXT:    movaps %xmm0, {{[0-9]+}}(%rsp)
+; WIN64-NEXT:    leaq {{[0-9]+}}(%rsp), %rcx
+; WIN64-NEXT:    callq __floattisf
+; WIN64-NEXT:    addq $56, %rsp
+; WIN64-NEXT:    retq
+  %2 = load i128, i128* %0, align 16
+  %3 = sitofp i128 %2 to float
+  ret float %3
+}
+
+define float @ui128_to_float(i128* nocapture readonly %0) nounwind {
+; WIN64-LABEL: ui128_to_float:
+; WIN64:       # %bb.0:
+; WIN64-NEXT:    subq $56, %rsp
+; WIN64-NEXT:    movaps (%rcx), %xmm0
+; WIN64-NEXT:    movaps %xmm0, {{[0-9]+}}(%rsp)
+; WIN64-NEXT:    leaq {{[0-9]+}}(%rsp), %rcx
+; WIN64-NEXT:    callq __floatuntisf
+; WIN64-NEXT:    addq $56, %rsp
+; WIN64-NEXT:    retq
+  %2 = load i128, i128* %0, align 16
+  %3 = uitofp i128 %2 to float
+  ret float %3
+}
+
+define void @i128_to_longdouble(x86_fp80* noalias nocapture sret(x86_fp80) align 16 %agg.result, i128* nocapture readonly %0) nounwind {
+; WIN64-LABEL: i128_to_longdouble:
+; WIN64:       # %bb.0:
+; WIN64-NEXT:    pushq %rsi
+; WIN64-NEXT:    subq $64, %rsp
+; WIN64-NEXT:    movq %rcx, %rsi
+; WIN64-NEXT:    movaps (%rdx), %xmm0
+; WIN64-NEXT:    movaps %xmm0, {{[0-9]+}}(%rsp)
+; WIN64-NEXT:    leaq {{[0-9]+}}(%rsp), %rcx
+; WIN64-NEXT:    leaq {{[0-9]+}}(%rsp), %rdx
+; WIN64-NEXT:    callq __floattixf
+; WIN64-NEXT:    fldt {{[0-9]+}}(%rsp)
+; WIN64-NEXT:    fstpt (%rsi)
+; WIN64-NEXT:    movq %rsi, %rax
+; WIN64-NEXT:    addq $64, %rsp
+; WIN64-NEXT:    popq %rsi
+; WIN64-NEXT:    retq
+  %2 = load i128, i128* %0, align 16
+  %3 = sitofp i128 %2 to x86_fp80
+  store x86_fp80 %3, x86_fp80* %agg.result, align 16
+  ret void
+}
+
+define void @ui128_to_longdouble(x86_fp80* noalias nocapture sret(x86_fp80) align 16 %agg.result, i128* nocapture readonly %0) nounwind {
+; WIN64-LABEL: ui128_to_longdouble:
+; WIN64:       # %bb.0:
+; WIN64-NEXT:    pushq %rsi
+; WIN64-NEXT:    subq $64, %rsp
+; WIN64-NEXT:    movq %rcx, %rsi
+; WIN64-NEXT:    movaps (%rdx), %xmm0
+; WIN64-NEXT:    movaps %xmm0, {{[0-9]+}}(%rsp)
+; WIN64-NEXT:    leaq {{[0-9]+}}(%rsp), %rcx
+; WIN64-NEXT:    leaq {{[0-9]+}}(%rsp), %rdx
+; WIN64-NEXT:    callq __floatuntixf
+; WIN64-NEXT:    fldt {{[0-9]+}}(%rsp)
+; WIN64-NEXT:    fstpt (%rsi)
+; WIN64-NEXT:    movq %rsi, %rax
+; WIN64-NEXT:    addq $64, %rsp
+; WIN64-NEXT:    popq %rsi
+; WIN64-NEXT:    retq
+  %2 = load i128, i128* %0, align 16
+  %3 = uitofp i128 %2 to x86_fp80
+  store x86_fp80 %3, x86_fp80* %agg.result, align 16
+  ret void
+}