diff --git a/clang/lib/AST/ExprConstant.cpp b/clang/lib/AST/ExprConstant.cpp
--- a/clang/lib/AST/ExprConstant.cpp
+++ b/clang/lib/AST/ExprConstant.cpp
@@ -11177,6 +11177,15 @@
       }
     }
 
+    // Avoid emiting call for runtime decision on PowerPC 32-bit
+    // The lock free possibilities on this platform are covered by the lines 
+    // above and we know in advance other cases require lock.
+    // This may need to be restricted to specific operating systems in the future,
+    // as some (perhaps AIX) might provide libatomic and prefer to use it instead
+    if (Info.Ctx.getTargetInfo().getTriple().getArch() == llvm::Triple::ppc) {
+        return Success(0, E);
+    }
+
     return BuiltinOp == Builtin::BI__atomic_always_lock_free ?
         Success(0, E) : Error(E);
   }
diff --git a/compiler-rt/lib/builtins/atomic.c b/compiler-rt/lib/builtins/atomic.c
--- a/compiler-rt/lib/builtins/atomic.c
+++ b/compiler-rt/lib/builtins/atomic.c
@@ -119,13 +119,20 @@
   return locks + (hash & SPINLOCK_MASK);
 }
 
-/// Macros for determining whether a size is lock free.  Clang can not yet
-/// codegen __atomic_is_lock_free(16), so for now we assume 16-byte values are
-/// not lock free.
+/// Macros for determining whether a size is lock free.
 #define IS_LOCK_FREE_1 __c11_atomic_is_lock_free(1)
 #define IS_LOCK_FREE_2 __c11_atomic_is_lock_free(2)
 #define IS_LOCK_FREE_4 __c11_atomic_is_lock_free(4)
+
+/// 32 bit PowerPC doesn't support 8-byte lock_free atomics
+#if !defined(__powerpc64__) && defined(__powerpc__)
+#define IS_LOCK_FREE_8 0
+#else
 #define IS_LOCK_FREE_8 __c11_atomic_is_lock_free(8)
+#endif
+
+/// Clang can not yet codegen __atomic_is_lock_free(16), so for now we assume
+/// 16-byte values are not lock free.
 #define IS_LOCK_FREE_16 0
 
 /// Macro that calls the compiler-generated lock-free versions of functions