diff --git a/clang/include/clang/Basic/BuiltinsPPC.def b/clang/include/clang/Basic/BuiltinsPPC.def
--- a/clang/include/clang/Basic/BuiltinsPPC.def
+++ b/clang/include/clang/Basic/BuiltinsPPC.def
@@ -113,6 +113,7 @@
 BUILTIN(__builtin_ppc_fnmsubs, "ffff", "")
 BUILTIN(__builtin_ppc_fre, "dd", "")
 BUILTIN(__builtin_ppc_fres, "ff", "")
+BUILTIN(__builtin_ppc_stbcx, "icD*i", "")
 
 BUILTIN(__builtin_ppc_get_timebase, "ULLi", "n")
 
diff --git a/clang/lib/Basic/Targets/PPC.cpp b/clang/lib/Basic/Targets/PPC.cpp
--- a/clang/lib/Basic/Targets/PPC.cpp
+++ b/clang/lib/Basic/Targets/PPC.cpp
@@ -118,6 +118,7 @@
   Builder.defineMacro("__fetch_and_swaplp", "__builtin_ppc_fetch_and_swaplp");
   Builder.defineMacro("__ldarx", "__builtin_ppc_ldarx");
   Builder.defineMacro("__lwarx", "__builtin_ppc_lwarx");
+  Builder.defineMacro("__stbcx", "__builtin_ppc_stbcx");
   Builder.defineMacro("__stdcx", "__builtin_ppc_stdcx");
   Builder.defineMacro("__stwcx", "__builtin_ppc_stwcx");
   Builder.defineMacro("__tdw", "__builtin_ppc_tdw");
diff --git a/clang/lib/Sema/SemaChecking.cpp b/clang/lib/Sema/SemaChecking.cpp
--- a/clang/lib/Sema/SemaChecking.cpp
+++ b/clang/lib/Sema/SemaChecking.cpp
@@ -3429,6 +3429,9 @@
   case PPC::BI__builtin_ppc_mtfsfi:
     return SemaBuiltinConstantArgRange(TheCall, 0, 0, 7) ||
            SemaBuiltinConstantArgRange(TheCall, 1, 0, 15);
+  case PPC::BI__builtin_ppc_stbcx:
+    return SemaFeatureCheck(*this, TheCall, "isa-v207-instructions",
+                            diag::err_ppc_builtin_only_on_arch, "8");
 #define CUSTOM_BUILTIN(Name, Intr, Types, Acc) \
   case PPC::BI__builtin_##Name: \
     return SemaBuiltinPPCMMACall(TheCall, Types);
diff --git a/clang/test/CodeGen/builtins-ppc-xlcompat-pwr8.c b/clang/test/CodeGen/builtins-ppc-xlcompat-pwr8.c
new file mode 100644
--- /dev/null
+++ b/clang/test/CodeGen/builtins-ppc-xlcompat-pwr8.c
@@ -0,0 +1,31 @@
+// REQUIRES: powerpc-registered-target
+// RUN: %clang_cc1 -triple powerpc64-unknown-unknown -emit-llvm %s \
+// RUN:   -target-cpu pwr8 -o - | FileCheck %s --check-prefix=CHECK-PWR8
+// RUN: %clang_cc1 -triple powerpc64le-unknown-unknown -emit-llvm %s \
+// RUN:   -target-cpu pwr8 -o - | FileCheck %s --check-prefix=CHECK-PWR8
+// RUN: %clang_cc1 -triple powerpc64-unknown-aix -emit-llvm %s \
+// RUN:   -target-cpu pwr8 -o - | FileCheck %s --check-prefix=CHECK-PWR8
+// RUN: %clang_cc1 -triple powerpc-unknown-aix %s -emit-llvm %s \
+// RUN:   -target-cpu pwr8 -o - | FileCheck %s --check-prefix=CHECK-PWR8
+// RUN: not %clang_cc1 -triple powerpc64-unknown-unknown -emit-llvm %s \
+// RUN:   -target-cpu pwr7 -o - 2>&1 | FileCheck %s -check-prefix=CHECK-NOPWR8
+// RUN: not %clang_cc1 -triple powerpc64-unknown-aix -emit-llvm %s \
+// RUN:   -target-cpu pwr7 -o - 2>&1 | FileCheck %s -check-prefix=CHECK-NOPWR8
+// RUN: not %clang_cc1 -triple powerpc-unknown-aix %s -emit-llvm %s \
+// RUN:   -target-cpu pwr7 -o - 2>&1 | FileCheck %s -check-prefix=CHECK-NOPWR8
+
+extern volatile char *c_addr;
+extern char c;
+
+// CHECK-PWR8-LABEL: @test_builtin_ppc_stbcx(
+// CHECK-PWR8:         [[TMP0:%.*]] = load i8*, i8** @c_addr, align {{[0-9]+}}
+// CHECK-PWR8-NEXT:    [[TMP1:%.*]] = load i8, i8* @c, align 1
+// CHECK-PWR8-NEXT:    [[TMP2:%.*]] = sext i8 [[TMP1]] to i32
+// CHECK-PWR8-NEXT:    [[TMP3:%.*]] = call i32 @llvm.ppc.stbcx(i8* [[TMP0]], i32 [[TMP2]])
+// CHECK-PWR8-NEXT:    ret i32 [[TMP3]]
+
+// CHECK-NOPWR8: error: this builtin is only valid on POWER8 or later CPUs
+
+int test_builtin_ppc_stbcx() {
+  return __builtin_ppc_stbcx(c_addr, c);
+}
diff --git a/llvm/include/llvm/IR/IntrinsicsPowerPC.td b/llvm/include/llvm/IR/IntrinsicsPowerPC.td
--- a/llvm/include/llvm/IR/IntrinsicsPowerPC.td
+++ b/llvm/include/llvm/IR/IntrinsicsPowerPC.td
@@ -1559,6 +1559,9 @@
                       Intrinsic<[],[],[]>;
   def int_ppc_iospace_eieio : GCCBuiltin<"__builtin_ppc_iospace_eieio">,
                               Intrinsic<[],[],[]>;
+  def int_ppc_stbcx : GCCBuiltin<"__builtin_ppc_stbcx">,
+                      Intrinsic<[llvm_i32_ty], [llvm_ptr_ty, llvm_i32_ty],
+                                [IntrWriteMem]>;
   def int_ppc_stdcx : GCCBuiltin<"__builtin_ppc_stdcx">,
                       Intrinsic<[llvm_i32_ty], [llvm_ptr_ty, llvm_i64_ty],
                                 [IntrWriteMem]>;
diff --git a/llvm/lib/Target/PowerPC/PPCInstrInfo.td b/llvm/lib/Target/PowerPC/PPCInstrInfo.td
--- a/llvm/lib/Target/PowerPC/PPCInstrInfo.td
+++ b/llvm/lib/Target/PowerPC/PPCInstrInfo.td
@@ -5459,6 +5459,8 @@
 
 def : Pat<(int_ppc_stwcx ForceXForm:$dst, gprc:$A),
           (STWCX gprc:$A, ForceXForm:$dst)>;
+def : Pat<(int_ppc_stbcx ForceXForm:$dst, gprc:$A),
+          (STBCX gprc:$A, ForceXForm:$dst)>;
 def : Pat<(int_ppc_tw gprc:$A, gprc:$B, i32:$IMM),
           (TW $IMM, $A, $B)>;
 def : Pat<(int_ppc_trap gprc:$A),
diff --git a/llvm/test/CodeGen/PowerPC/builtins-ppc-xlcompat-LoadReserve-StoreCond.ll b/llvm/test/CodeGen/PowerPC/builtins-ppc-xlcompat-LoadReserve-StoreCond.ll
--- a/llvm/test/CodeGen/PowerPC/builtins-ppc-xlcompat-LoadReserve-StoreCond.ll
+++ b/llvm/test/CodeGen/PowerPC/builtins-ppc-xlcompat-LoadReserve-StoreCond.ll
@@ -50,3 +50,25 @@
   %1 = tail call i32 @llvm.ppc.stwcx(i8* %0, i32 %b)
   ret i32 %1
 }
+
+declare i32 @llvm.ppc.stbcx(i8*, i32)
+define signext i32 @test_stbcx(i8* %addr, i8 signext %val) {
+; CHECK-64-LABEL: test_stbcx:
+; CHECK-64:       # %bb.0: # %entry
+; CHECK-64-NEXT:    stbcx. 4, 0, 3
+; CHECK-64-NEXT:    mfocrf 3, 128
+; CHECK-64-NEXT:    srwi 3, 3, 28
+; CHECK-64-NEXT:    extsw 3, 3
+; CHECK-64-NEXT:    blr
+;
+; CHECK-32-LABEL: test_stbcx:
+; CHECK-32:       # %bb.0: # %entry
+; CHECK-32-NEXT:    stbcx. 4, 0, 3
+; CHECK-32-NEXT:    mfocrf 3, 128
+; CHECK-32-NEXT:    srwi 3, 3, 28
+; CHECK-32-NEXT:    blr
+entry:
+  %conv = sext i8 %val to i32
+  %0 = tail call i32 @llvm.ppc.stbcx(i8* %addr, i32 %conv)
+  ret i32 %0
+}