Index: llvm/trunk/include/llvm/ADT/Triple.h
===================================================================
--- llvm/trunk/include/llvm/ADT/Triple.h
+++ llvm/trunk/include/llvm/ADT/Triple.h
@@ -523,6 +523,16 @@
     return getOS() == Triple::Linux;
   }
 
+  /// Tests whether the OS is kFreeBSD.
+  bool isOSKFreeBSD() const {
+    return getOS() == Triple::KFreeBSD;
+  }
+
+  /// Tests whether the OS uses glibc.
+  bool isOSGlibc() const {
+    return getOS() == Triple::Linux || getOS() == Triple::KFreeBSD;
+  }
+
   /// Tests whether the OS uses the ELF binary format.
   bool isOSBinFormatELF() const {
     return getObjectFormat() == Triple::ELF;
Index: llvm/trunk/lib/Target/X86/X86ISelDAGToDAG.cpp
===================================================================
--- llvm/trunk/lib/Target/X86/X86ISelDAGToDAG.cpp
+++ llvm/trunk/lib/Target/X86/X86ISelDAGToDAG.cpp
@@ -719,7 +719,7 @@
   // For more information see http://people.redhat.com/drepper/tls.pdf
   if (ConstantSDNode *C = dyn_cast<ConstantSDNode>(Address))
     if (C->getSExtValue() == 0 && AM.Segment.getNode() == nullptr &&
-        Subtarget->isTargetLinux())
+        Subtarget->isTargetGlibc())
       switch (N->getPointerInfo().getAddrSpace()) {
       case 256:
         AM.Segment = CurDAG->getRegister(X86::GS, MVT::i16);
Index: llvm/trunk/lib/Target/X86/X86ISelLowering.cpp
===================================================================
--- llvm/trunk/lib/Target/X86/X86ISelLowering.cpp
+++ llvm/trunk/lib/Target/X86/X86ISelLowering.cpp
@@ -1919,7 +1919,9 @@
 }
 
 Value *X86TargetLowering::getIRStackGuard(IRBuilder<> &IRB) const {
-  if (!Subtarget.isTargetLinux())
+  // glibc has a special slot for the stack guard in tcbhead_t, use it instead
+  // of the usual global variable (see sysdeps/{i386,x86_64}/nptl/tls.h)
+  if (!Subtarget.isTargetGlibc())
     return TargetLowering::getIRStackGuard(IRB);
 
   // %fs:0x28, unless we're using a Kernel code model, in which case it's %gs:
@@ -1932,7 +1934,7 @@
 }
 
 void X86TargetLowering::insertSSPDeclarations(Module &M) const {
-  if (!Subtarget.isTargetLinux())
+  if (!Subtarget.isTargetGlibc())
     TargetLowering::insertSSPDeclarations(M);
 }
 
Index: llvm/trunk/lib/Target/X86/X86Subtarget.h
===================================================================
--- llvm/trunk/lib/Target/X86/X86Subtarget.h
+++ llvm/trunk/lib/Target/X86/X86Subtarget.h
@@ -467,6 +467,8 @@
   bool isTargetMachO() const { return TargetTriple.isOSBinFormatMachO(); }
 
   bool isTargetLinux() const { return TargetTriple.isOSLinux(); }
+  bool isTargetKFreeBSD() const { return TargetTriple.isOSKFreeBSD(); }
+  bool isTargetGlibc() const { return TargetTriple.isOSGlibc(); }
   bool isTargetAndroid() const { return TargetTriple.isAndroid(); }
   bool isTargetNaCl() const { return TargetTriple.isOSNaCl(); }
   bool isTargetNaCl32() const { return isTargetNaCl() && !is64Bit(); }
Index: llvm/trunk/lib/Target/X86/X86Subtarget.cpp
===================================================================
--- llvm/trunk/lib/Target/X86/X86Subtarget.cpp
+++ llvm/trunk/lib/Target/X86/X86Subtarget.cpp
@@ -262,12 +262,12 @@
   assert((!In64BitMode || HasX86_64) &&
          "64-bit code requested on a subtarget that doesn't support it!");
 
-  // Stack alignment is 16 bytes on Darwin, Linux and Solaris (both
+  // Stack alignment is 16 bytes on Darwin, Linux, kFreeBSD and Solaris (both
   // 32 and 64 bit) and for all 64-bit targets.
   if (StackAlignOverride)
     stackAlignment = StackAlignOverride;
   else if (isTargetDarwin() || isTargetLinux() || isTargetSolaris() ||
-           In64BitMode)
+           isTargetKFreeBSD() || In64BitMode)
     stackAlignment = 16;
 }
 
Index: llvm/trunk/test/CodeGen/X86/stack-align2.ll
===================================================================
--- llvm/trunk/test/CodeGen/X86/stack-align2.ll
+++ llvm/trunk/test/CodeGen/X86/stack-align2.ll
@@ -1,7 +1,9 @@
 ; RUN: llc < %s -mcpu=generic -mtriple=i386-linux | FileCheck %s -check-prefix=LINUX-I386
+; RUN: llc < %s -mcpu=generic -mtriple=i386-kfreebsd | FileCheck %s -check-prefix=KFREEBSD-I386
 ; RUN: llc < %s -mcpu=generic -mtriple=i386-netbsd | FileCheck %s -check-prefix=NETBSD-I386
 ; RUN: llc < %s -mcpu=generic -mtriple=i686-apple-darwin8 | FileCheck %s -check-prefix=DARWIN-I386
 ; RUN: llc < %s -mcpu=generic -mtriple=x86_64-linux | FileCheck %s -check-prefix=LINUX-X86_64
+; RUN: llc < %s -mcpu=generic -mtriple=x86_64-kfreebsd | FileCheck %s -check-prefix=KFREEBSD-X86_64
 ; RUN: llc < %s -mcpu=generic -mtriple=x86_64-netbsd | FileCheck %s -check-prefix=NETBSD-X86_64
 ; RUN: llc < %s -mcpu=generic -mtriple=x86_64-apple-darwin8 | FileCheck %s -check-prefix=DARWIN-X86_64
 
@@ -11,6 +13,7 @@
   ret i32 0
 
 ; LINUX-I386:     subl	$12, %esp
+; KFREEBSD-I386:  subl	$12, %esp
 ; DARWIN-I386:    subl	$12, %esp
 ; NETBSD-I386-NOT: subl	{{.*}}, %esp
 
@@ -20,6 +23,8 @@
 ; DARWIN-X86_64-NOT: subq	{{.*}}, %rsp
 ; NETBSD-X86_64:     pushq %{{.*}}
 ; NETBSD-X86_64-NOT: subq	{{.*}}, %rsp
+; KFREEBSD-X86_64:     pushq %{{.*}}
+; KFREEBSD-X86_64-NOT: subq	{{.*}}, %rsp
 }
 
 declare void @test2()
Index: llvm/trunk/test/CodeGen/X86/stack-protector-target.ll
===================================================================
--- llvm/trunk/test/CodeGen/X86/stack-protector-target.ll
+++ llvm/trunk/test/CodeGen/X86/stack-protector-target.ll
@@ -3,6 +3,8 @@
 ; RUN: llc -mtriple=x86_64-linux < %s -o - | FileCheck --check-prefix=LINUX-X64 %s
 ; RUN: llc -mtriple=i386-linux-android < %s -o - | FileCheck --check-prefix=LINUX-I386 %s
 ; RUN: llc -mtriple=x86_64-linux-android < %s -o - | FileCheck --check-prefix=LINUX-X64 %s
+; RUN: llc -mtriple=i386-kfreebsd < %s -o - | FileCheck --check-prefix=LINUX-I386 %s
+; RUN: llc -mtriple=x86_64-kfreebsd < %s -o - | FileCheck --check-prefix=LINUX-X64 %s
 
 define void @_Z1fv() sspreq {
 entry: