diff --git a/clang/lib/CodeGen/TargetInfo.cpp b/clang/lib/CodeGen/TargetInfo.cpp
--- a/clang/lib/CodeGen/TargetInfo.cpp
+++ b/clang/lib/CodeGen/TargetInfo.cpp
@@ -1108,6 +1108,7 @@
   bool IsWin32StructABI;
   bool IsSoftFloatABI;
   bool IsMCUABI;
+  bool IsLinuxABI;
   unsigned DefaultNumRegisterParameters;
 
   static bool isRegisterSize(unsigned Size) {
@@ -1173,6 +1174,7 @@
       IsWin32StructABI(Win32StructABI),
       IsSoftFloatABI(SoftFloatABI),
       IsMCUABI(CGT.getTarget().getTriple().isOSIAMCU()),
+      IsLinuxABI(CGT.getTarget().getTriple().isOSLinux()),
       DefaultNumRegisterParameters(NumRegisterParameters) {}
 
   bool shouldPassIndirectlyForSwift(ArrayRef<llvm::Type*> scalars,
@@ -1597,6 +1599,9 @@
   if (Align <= MinABIStackAlignInBytes)
     return 0; // Use default alignment.
 
+  if (IsLinuxABI && Ty->isFloatingType() && getContext().getTypeSize(Ty) == 128)
+    return 16;
+
   // On non-Darwin, the stack type alignment is always 4.
   if (!IsDarwinVectorABI) {
     // Set explicit alignment, since we may need to realign the top.
@@ -1890,6 +1895,9 @@
     return getIndirectResult(Ty, /*ByVal=*/false, State);
   }
 
+  if (IsLinuxABI && Ty->isFloatingType() && getContext().getTypeSize(Ty) == 128)
+    return getIndirectResult(Ty, /*ByVal=*/true, State);
+
   if (InReg)
     return ABIArgInfo::getDirectInReg();
   return ABIArgInfo::getDirect();
diff --git a/clang/test/CodeGen/x86-long-double.cpp b/clang/test/CodeGen/x86-long-double.cpp
--- a/clang/test/CodeGen/x86-long-double.cpp
+++ b/clang/test/CodeGen/x86-long-double.cpp
@@ -16,14 +16,14 @@
 // RUN: %clang_cc1 %s -emit-llvm -o - -triple=x86_64-apple-darwin -mlong-double-64 | \
 // RUN:   FileCheck --check-prefixes=FP64,FP64-X64 %s
 
-// RUN: %clang_cc1 %s -emit-llvm -o - -triple=i686 -mlong-double-128 | \
-// RUN:   FileCheck --check-prefix=FP128 %s
+// RUN: %clang_cc1 %s -emit-llvm -o - -triple=i386-pc-linux-gnu -mlong-double-128 | \
+// RUN:   FileCheck --check-prefixes=FP128,FP128-X32-LINUX %s
 // RUN: %clang_cc1 %s -emit-llvm -o - -triple=i686-apple-darwin -mlong-double-128 | \
-// RUN:   FileCheck --check-prefix=FP128 %s
+// RUN:   FileCheck --check-prefixes=FP128,FP128-X32-DARWIN %s
 // RUN: %clang_cc1 %s -emit-llvm -o - -triple=x86_64 -mlong-double-128 | \
-// RUN:   FileCheck --check-prefix=FP128 %s
+// RUN:   FileCheck --check-prefixes=FP128,FP128-X64 %s
 // RUN: %clang_cc1 %s -emit-llvm -o - -triple=x86_64-apple-darwin -mlong-double-128 | \
-// RUN:   FileCheck --check-prefix=FP128 %s
+// RUN:   FileCheck --check-prefixes=FP128,FP128-X64 %s
 
 // Check -malign-double increases the alignment from 4 to 8 on x86-32.
 // RUN: %clang_cc1 %s -emit-llvm -o - -triple=i686 -mlong-double-64 \
@@ -53,4 +53,6 @@
 
 // FP64: double @_Z3fooe(double %d)
 // FP80: x86_fp80 @_Z3fooe(x86_fp80 %d)
-// FP128: fp128 @_Z3foog(fp128 %d)
+// FP128-X32-LINUX: fp128 @_Z3foog(fp128* byval(fp128) align 16 %0)
+// FP128-X32-DARWIN: fp128 @_Z3foog(fp128 %d)
+// FP128-X64: fp128 @_Z3foog(fp128 %d)
diff --git a/clang/test/CodeGen/x86_32-fp128-call-conv-linux.c b/clang/test/CodeGen/x86_32-fp128-call-conv-linux.c
new file mode 100644
--- /dev/null
+++ b/clang/test/CodeGen/x86_32-fp128-call-conv-linux.c
@@ -0,0 +1,28 @@
+// RUN: %clang_cc1 -mlong-double-128 -w -fblocks -ffreestanding -triple i386-pc-linux-gnu -emit-llvm -o %t %s || FileCheck < %t %s
+
+
+// CHECK-LABEL: define void @testfp128
+// CHECK-NEXT:  %a.addr = alloca fp128, align 16
+// CHECK-NEXT:  %a = load fp128, fp128* %0, align 16
+// CHECK-NEXT:  store fp128 %a, fp128* %a.addr, align 16
+void testfp128(__float128 a) {
+  return;
+}
+
+// CHECK-LABEL: define void @testlongdouble
+// CHECK-NEXT:  %a.addr = alloca fp128, align 16
+// CHECK-NEXT:  %a = load fp128, fp128* %0, align 16
+// CHECK-NEXT:  store fp128 %a, fp128* %a.addr, align 16
+void testlongdouble(long double a) {
+  return;
+}
+
+// CHECK-LABEL: define void @testPassArguments
+// CHECK:       call void @testfp128(fp128* byval(fp128) align 16 %{{.*}})
+// CHECK:       call void @testlongdouble(fp128* byval(fp128) align 16 %{{.*}})
+void testPassArguments() {
+  __float128 a=1.0;
+  testfp128(a);
+  testlongdouble(a);
+  return;
+}
diff --git a/clang/test/CodeGenCXX/float128-declarations.cpp b/clang/test/CodeGenCXX/float128-declarations.cpp
--- a/clang/test/CodeGenCXX/float128-declarations.cpp
+++ b/clang/test/CodeGenCXX/float128-declarations.cpp
@@ -3,7 +3,7 @@
 // RUN: %clang_cc1 -emit-llvm -triple powerpc64le-unknown-unknown \
 // RUN:   -target-feature +float128 -std=c++11 %s -o - | FileCheck %s
 // RUN: %clang_cc1 -emit-llvm -triple i386-unknown-linux-gnu -std=c++11 \
-// RUN:   %s -o - | FileCheck %s -check-prefix=CHECK-X86
+// RUN:   %s -o - | FileCheck %s -check-prefix=CHECK-X86-32-LINUX
 // RUN: %clang_cc1 -emit-llvm -triple x86_64-unknown-linux-gnu -std=c++11 \
 // RUN:   %s -o - | FileCheck %s -check-prefix=CHECK-X86
 // RUN: %clang_cc1 -emit-llvm -triple i686-pc-openbsd -std=c++11 \
@@ -123,3 +123,25 @@
 // CHECK-X86-DAG: [[F4L:%[a-z0-9]+]] = load fp128, fp128* %f4l
 // CHECK-X86-DAG: [[INC:%[a-z0-9]+]] = fadd fp128 [[F4L]], 0xL00000000000000003FFF000000000000
 // CHECK-X86-DAG: store fp128 [[INC]], fp128* %f4l
+
+// CHECK-X86-32-LINUX-DAG: @_ZN12_GLOBAL__N_13f1nE = internal global fp128 0xL00000000000000000000000000000000
+// CHECK-X86-32-LINUX-DAG: @_ZN12_GLOBAL__N_13f2nE = internal global fp128 0xL00000000000000004004080000000000
+// CHECK-X86-32-LINUX-DAG: @_ZN12_GLOBAL__N_15arr1nE = internal global [10 x fp128]
+// CHECK-X86-32-LINUX-DAG: @_ZN12_GLOBAL__N_15arr2nE = internal global [3 x fp128] [fp128 0xL33333333333333333FFF333333333333, fp128 0xL00000000000000004000800000000000, fp128 0xL00000000000000004025176592E00000]
+// CHECK-X86-32-LINUX-DAG: define internal fp128 @_ZN12_GLOBAL__N_16func1nERKg(fp128*
+// CHECK-X86-32-LINUX-DAG: @f1f = global fp128 0xL00000000000000000000000000000000
+// CHECK-X86-32-LINUX-DAG: @f2f = global fp128 0xL33333333333333334004033333333333
+// CHECK-X86-32-LINUX-DAG: @arr1f = global [10 x fp128]
+// CHECK-X86-32-LINUX-DAG: @arr2f = global [3 x fp128] [fp128 0xL3333333333333333BFFF333333333333, fp128 0xL0000000000000000C000800000000000, fp128 0xL0000000000000000C025176592E00000]
+// CHECK-X86-32-LINUX-DAG: declare fp128 @_Z6func1fg(fp128* byval(fp128) align 16) #3
+// CHECK-X86-32-LINUX-DAG: define linkonce_odr void @_ZN2C1C2Eg(%class.C1* %this, fp128* byval(fp128) align 16 %0)
+// CHECK-X86-32-LINUX-DAG: define linkonce_odr fp128 @_ZN2C16func2cEg(fp128* byval(fp128) align 16 %0)
+// CHECK-X86-32-LINUX-DAG: define linkonce_odr fp128 @_Z6func1tIgET_S0_(fp128* byval(fp128) align 16 %0)
+// CHECK-X86-32-LINUX-DAG: @__const.main.s1 = private unnamed_addr constant %struct.S1 { fp128 0xL00000000000000004006080000000000 }
+// CHECK-X86-32-LINUX-DAG: store fp128 0xLF0AFD0EBFF292DCE42E0B38CDD83F26F, fp128* %f1l, align 16
+// CHECK-X86-32-LINUX-DAG: store fp128 0xL00000000000000008000000000000000, fp128* %f2l, align 16
+// CHECK-X86-32-LINUX-DAG: store fp128 0xLFFFFFFFFFFFFFFFF7FFEFFFFFFFFFFFF, fp128* %f3l, align 16
+// CHECK-X86-32-LINUX-DAG: store fp128 0xL0000000000000000BFFF000000000000, fp128* %f5l, align 16
+// CHECK-X86-32-LINUX-DAG: [[F4L:%[a-z0-9]+]] = load fp128, fp128* %f4l
+// CHECK-X86-32-LINUX-DAG: [[INC:%[a-z0-9]+]] = fadd fp128 [[F4L]], 0xL00000000000000003FFF000000000000
+// CHECK-X86-32-LINUX-DAG: store fp128 [[INC]], fp128* %f4l