diff --git a/include/boost/atomic/detail/config.hpp b/include/boost/atomic/detail/config.hpp
index 6af8d50..51eed39 100644
--- a/include/boost/atomic/detail/config.hpp
+++ b/include/boost/atomic/detail/config.hpp
@@ -46,7 +46,7 @@
 #endif
 
 #if defined(__CUDACC__)
-// nvcc does not support alternatives in asm statement constraints
+// nvcc does not support alternatives ("q,m") in asm statement constraints
 #define BOOST_ATOMIC_DETAIL_NO_ASM_CONSTRAINT_ALTERNATIVES
 // nvcc does not support condition code register ("cc") clobber in asm statements
 #define BOOST_ATOMIC_DETAIL_NO_ASM_CLOBBER_CC
diff --git a/include/boost/atomic/detail/ops_gcc_x86_dcas.hpp b/include/boost/atomic/detail/ops_gcc_x86_dcas.hpp
index a9c0ade..fd2a3e6 100644
--- a/include/boost/atomic/detail/ops_gcc_x86_dcas.hpp
+++ b/include/boost/atomic/detail/ops_gcc_x86_dcas.hpp
@@ -250,13 +250,8 @@ struct gcc_dcas_x86
         (
             "lock; cmpxchg8b %[dest]\n\t"
             "sete %[success]\n\t"
-#if !defined(BOOST_ATOMIC_DETAIL_NO_ASM_CONSTRAINT_ALTERNATIVES)
-            : "+A,A" (expected), [dest] "+m,m" (storage), [success] "=q,m" (success)
-            : "b,b" ((uint32_t)desired), "c,c" ((uint32_t)(desired >> 32))
-#else
-            : "+A" (expected), [dest] "+m" (storage), [success] "=q" (success)
+            : "+A" (expected), [dest] "+m" (storage), [success] "=qm" (success)
             : "b" ((uint32_t)desired), "c" ((uint32_t)(desired >> 32))
-#endif
             : BOOST_ATOMIC_DETAIL_ASM_CLOBBER_CC_COMMA "memory"
         );
 #endif // defined(BOOST_ATOMIC_DETAIL_ASM_HAS_FLAG_OUTPUTS)
@@ -476,13 +471,8 @@ struct gcc_dcas_x86_64
         (
             "lock; cmpxchg16b %[dest]\n\t"
             "sete %[success]\n\t"
-#if !defined(BOOST_ATOMIC_DETAIL_NO_ASM_CONSTRAINT_ALTERNATIVES)
-            : "+A,A" (expected), [dest] "+m,m" (storage), [success] "=q,m" (success)
-            : "b,b" (reinterpret_cast< const aliasing_uint64_t* >(&desired)[0]), "c,c" (reinterpret_cast< const aliasing_uint64_t* >(&desired)[1])
-#else
-            : "+A" (expected), [dest] "+m" (storage), [success] "=q" (success)
+            : "+A" (expected), [dest] "+m" (storage), [success] "=qm" (success)
             : "b" (reinterpret_cast< const aliasing_uint64_t* >(&desired)[0]), "c" (reinterpret_cast< const aliasing_uint64_t* >(&desired)[1])
-#endif
             : BOOST_ATOMIC_DETAIL_ASM_CLOBBER_CC_COMMA "memory"
         );
 #endif // defined(BOOST_ATOMIC_DETAIL_ASM_HAS_FLAG_OUTPUTS)