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Simplified asm constraints to avoid comma-separated alternatives.

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Alternatives are not supported by all compilers, and for the purpose we're using
them we can use constraint-local alternatives (i.e. "qm" instead of "q,m").
Additionally, this reduces duplication of other constraints in the asm block.
This commit is contained in:
Andrey Semashev
2018-02-04 15:24:31 +03:00
parent fe57fa0375
commit acec1a7668
2 changed files with 3 additions and 13 deletions
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2
include/boost/atomic/detail/config.hpp
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@@ -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

14
include/boost/atomic/detail/ops_gcc_x86_dcas.hpp
View File

@@ -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)