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Using Clang __builtin_assume if available. #5

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Merged
foonathan merged 2 commits into from
Jan 10, 2017
Merged

Using Clang __builtin_assume if available. #5

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3d7eab9
Using Clang __builtin_assume if available.
verri Jan 9, 2017
1c80d36
Fixed warning in clang.
verri Jan 9, 2017
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2 changes: 2 additions & 0 deletions README.md
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Original file line number Diff line number Diff line change
Expand Up @@ -54,6 +54,8 @@ The options are named like the macros.

<pre><code class="language-cpp">#define <a href='doc_debug_assert.md#debug_assert.hpp'>DEBUG_ASSERT_MARK_UNREACHABLE</a>

#define <a href='doc_debug_assert.md#debug_assert.hpp'>DEBUG_ASSERT_PURE_FUNCTION</a>

#define <a href='doc_debug_assert.md#debug_assert.hpp'>DEBUG_ASSERT_ASSUME</a>(Expr)

#define <a href='doc_debug_assert.md#debug_assert.hpp'>DEBUG_ASSERT_FORCE_INLINE</a>
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22 changes: 20 additions & 2 deletions debug_assert.hpp
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Expand Up @@ -43,6 +43,24 @@
#endif
#endif

#ifndef DEBUG_ASSERT_PURE_FUNCTION
#ifdef __GNUC__
#define DEBUG_ASSERT_PURE_FUNCTION __attribute__((pure))
#else
/// Hint to the compiler that a function is pure.
/// Define it yourself prior to including the header to override it.
#define DEBUG_ASSERT_PURE_FUNCTION
#endif
#endif

// checking for clang must come first because clang also defines __GNUC__.
#if !defined(DEBUG_ASSERT_ASSUME) && defined(__clang__)
// __has_builtin may not work in other compilers.
#if __has_builtin(__builtin_assume)
#define DEBUG_ASSERT_ASSUME(Expr) __builtin_assume(Expr)

@foonathan foonathan Jan 9, 2017

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Can you use defined(__clang__) && __has_builtin... there and then just have a single #elif defined(__GNUC__)? Avoids the repetition.

#endif
#endif

#ifndef DEBUG_ASSERT_ASSUME
#ifdef __GNUC__
#define DEBUG_ASSERT_ASSUME(Expr) \
Expand Down Expand Up @@ -309,7 +327,7 @@ namespace debug_assert
/// This should not be necessary, the regular version is optimized away
/// completely.
#define DEBUG_ASSERT(Expr, ...) \
debug_assert::detail::do_assert([&]() noexcept { return Expr; }, \
debug_assert::detail::do_assert([&]() DEBUG_ASSERT_PURE_FUNCTION noexcept { return Expr; }, \
DEBUG_ASSERT_CUR_SOURCE_LOCATION, #Expr, __VA_ARGS__)

/// Marks a branch as unreachable.
Expand All @@ -333,7 +351,7 @@ namespace debug_assert
/// This should not be necessary, the regular version is optimized away
/// completely.
#define DEBUG_UNREACHABLE(...) \
debug_assert::detail::do_assert([&]() noexcept { return false; }, \
debug_assert::detail::do_assert([&]() DEBUG_ASSERT_PURE_FUNCTION noexcept { return false; }, \
DEBUG_ASSERT_CUR_SOURCE_LOCATION, "", __VA_ARGS__)
#else
#define DEBUG_ASSERT(Expr, ...) DEBUG_ASSERT_ASSUME(Expr)
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