Remove overzeleous assertions in pg_atomic_flag code.

The atomics code asserts proper alignment in various places. That's
mainly because the alignment of 64bit integers is not sufficient for
atomic operations on all platforms. Some ABIs only have four byte
alignment, but don't have atomic behavior when crossing page
boundaries.

The flags code isn't affected by that however, as the type alignment
always is sufficient for atomic operations. Nevertheless the code
asserted alignment requirements. Before 8c3debbb it was only broken on
hppa, after it probably affect further platforms.

Thus remove the assertions for pg_atomic_flag operators.

Per buildfarm animal pademelon.

Discussion: https://postgr.es/m/7223.1523124425@sss.pgh.pa.us
Backpatch: 9.5-

diff --git a/src/include/port/atomics.h b/src/include/port/atomics.h
index 0b506fcbc0b19ad0233554bb9a50aa751bd27b19..005664f4ebd5ef54c4c7398dd7b71a557d6b262f 100644 (file)
--- a/src/include/port/atomics.h
+++ b/src/include/port/atomics.h
@@ -215,8 +215,6 @@ STATIC_IF_INLINE_DECLARE uint64 pg_atomic_sub_fetch_u64(volatile pg_atomic_uint6
 STATIC_IF_INLINE_DECLARE void
 pg_atomic_init_flag(volatile pg_atomic_flag *ptr)
 {
-       AssertPointerAlignment(ptr, sizeof(*ptr));
-
        pg_atomic_init_flag_impl(ptr);
 }
 
@@ -230,8 +228,6 @@ pg_atomic_init_flag(volatile pg_atomic_flag *ptr)
 STATIC_IF_INLINE_DECLARE bool
 pg_atomic_test_set_flag(volatile pg_atomic_flag *ptr)
 {
-       AssertPointerAlignment(ptr, sizeof(*ptr));
-
        return pg_atomic_test_set_flag_impl(ptr);
 }
 
@@ -245,8 +241,6 @@ pg_atomic_test_set_flag(volatile pg_atomic_flag *ptr)
 STATIC_IF_INLINE_DECLARE bool
 pg_atomic_unlocked_test_flag(volatile pg_atomic_flag *ptr)
 {
-       AssertPointerAlignment(ptr, sizeof(*ptr));
-
        return pg_atomic_unlocked_test_flag_impl(ptr);
 }
 
@@ -258,8 +252,6 @@ pg_atomic_unlocked_test_flag(volatile pg_atomic_flag *ptr)
 STATIC_IF_INLINE_DECLARE void
 pg_atomic_clear_flag(volatile pg_atomic_flag *ptr)
 {
-       AssertPointerAlignment(ptr, sizeof(*ptr));
-
        pg_atomic_clear_flag_impl(ptr);
 }