diff --git a/clang/lib/Basic/Targets/OSTargets.h b/clang/lib/Basic/Targets/OSTargets.h
--- a/clang/lib/Basic/Targets/OSTargets.h
+++ b/clang/lib/Basic/Targets/OSTargets.h
@@ -234,15 +234,24 @@
     // setting this to 1 is conforming even if all the basic source
     // character literals have the same encoding as char and wchar_t.
     Builder.defineMacro("__STDC_MB_MIGHT_NEQ_WC__", "1");
+
+    if (this->HasFloat128)
+      Builder.defineMacro("__FLOAT128__");
   }
 
 public:
   FreeBSDTargetInfo(const llvm::Triple &Triple, const TargetOptions &Opts)
       : OSTargetInfo<Target>(Triple, Opts) {
     switch (Triple.getArch()) {
-    default:
+    case llvm::Triple::ppc64le:
     case llvm::Triple::x86:
     case llvm::Triple::x86_64:
+      this->HasFloat128 = true;
+    }
+    switch (Triple.getArch()) {
+    case llvm::Triple::x86:
+    case llvm::Triple::x86_64:
+    default:
       this->MCountName = ".mcount";
       break;
     case llvm::Triple::mips:
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
@@ -2,6 +2,8 @@
 // RUN:   -target-feature +float128 -std=c++11 %s -o - | FileCheck %s
 // 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 x86_64-unknown-freebsd -std=c++11 \
+// RUN:   %s -o - | FileCheck %s -check-prefix=CHECK-X86
 // RUN: %clang_cc1 -emit-llvm -triple i386-unknown-linux-gnu -std=c++11 \
 // RUN:   %s -o - | FileCheck %s -check-prefix=CHECK-X86
 // RUN: %clang_cc1 -emit-llvm -triple x86_64-unknown-linux-gnu -std=c++11 \