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| author | Jonathan Wakely <redi@gcc.gnu.org> | 2015-09-17 16:46:04 +0100 |
|---|---|---|
| committer | Jonathan Wakely <redi@gcc.gnu.org> | 2015-09-17 16:46:04 +0100 |
| commit | 310055e7b481eb86318dc75dcf67f4091e395757 (patch) | |
| tree | 1f0c51ea5f77e0d267433e5aeeec1b8ac770b3b8 /gcc/builtins.c | |
| parent | 308fbc42903ba2f97c29eea52928802686a917f1 (diff) | |
| download | gcc-310055e7b481eb86318dc75dcf67f4091e395757.zip gcc-310055e7b481eb86318dc75dcf67f4091e395757.tar.gz gcc-310055e7b481eb86318dc75dcf67f4091e395757.tar.bz2 | |
Handle alignment in __atomic_is_lock_free
gcc:
2015-09-17 Richard Henderson <rth@redhat.com>
PR libstdc++/65913
* builtins.c (fold_builtin_atomic_always_lock_free): Handle fake
pointers that encode the alignment of the object.
libstdc++-v3:
2015-09-17 Jonathan Wakely <jwakely@redhat.com>
PR libstdc++/65913
* include/bits/atomic_base.h (__atomic_base<_TTp>::is_lock_free(),
__atomic_base<_PTp*>::is_lock_free()): Call the built-in with the
immediate pointer value, not a variable.
* include/std/atomic (atomic<T>::is_lock_free()): Likewise.
* testsuite/29_atomics/atomic/65913.cc: New.
From-SVN: r227878
Diffstat (limited to 'gcc/builtins.c')
| -rw-r--r-- | gcc/builtins.c | 16 |
1 files changed, 14 insertions, 2 deletions
diff --git a/gcc/builtins.c b/gcc/builtins.c index d79372c..aeec170 100644 --- a/gcc/builtins.c +++ b/gcc/builtins.c @@ -5635,8 +5635,20 @@ fold_builtin_atomic_always_lock_free (tree arg0, tree arg1) mode = mode_for_size (size, MODE_INT, 0); mode_align = GET_MODE_ALIGNMENT (mode); - if (TREE_CODE (arg1) == INTEGER_CST && INTVAL (expand_normal (arg1)) == 0) - type_align = mode_align; + if (TREE_CODE (arg1) == INTEGER_CST) + { + unsigned HOST_WIDE_INT val = UINTVAL (expand_normal (arg1)); + + /* Either this argument is null, or it's a fake pointer encoding + the alignment of the object. */ + val = val & -val; + val *= BITS_PER_UNIT; + + if (val == 0 || mode_align < val) + type_align = mode_align; + else + type_align = val; + } else { tree ttype = TREE_TYPE (arg1); |