diff options
Diffstat (limited to 'src')
| -rw-r--r-- | src/include/port/atomics/arch-ppc.h | 14 | ||||
| -rw-r--r-- | src/test/regress/regress.c | 8 |
2 files changed, 12 insertions, 10 deletions
diff --git a/src/include/port/atomics/arch-ppc.h b/src/include/port/atomics/arch-ppc.h index 68e66033ad7..a82ae38c1d6 100644 --- a/src/include/port/atomics/arch-ppc.h +++ b/src/include/port/atomics/arch-ppc.h @@ -72,14 +72,6 @@ typedef struct pg_atomic_uint64 * the __asm__. (That would remove the freedom to eliminate dead stores when * the caller ignores "expected", but few callers do.) * - * The cmpwi variant may be dead code. In gcc 7.2.0, - * __builtin_constant_p(*expected) always reports false. - * __atomic_compare_exchange_n() does use cmpwi when its second argument - * points to a constant. Hence, using this instead of - * __atomic_compare_exchange_n() nominally penalizes the generic.h - * pg_atomic_test_set_flag_impl(). Modern GCC will use the generic-gcc.h - * version, making the penalty theoretical only. - * * Recognizing constant "newval" would be superfluous, because there's no * immediate-operand version of stwcx. */ @@ -94,7 +86,8 @@ pg_atomic_compare_exchange_u32_impl(volatile pg_atomic_uint32 *ptr, #ifdef HAVE_I_CONSTRAINT__BUILTIN_CONSTANT_P if (__builtin_constant_p(*expected) && - *expected <= PG_INT16_MAX && *expected >= PG_INT16_MIN) + (int32) *expected <= PG_INT16_MAX && + (int32) *expected >= PG_INT16_MIN) __asm__ __volatile__( " sync \n" " lwarx %0,0,%5 \n" @@ -183,7 +176,8 @@ pg_atomic_compare_exchange_u64_impl(volatile pg_atomic_uint64 *ptr, /* Like u32, but s/lwarx/ldarx/; s/stwcx/stdcx/; s/cmpw/cmpd/ */ #ifdef HAVE_I_CONSTRAINT__BUILTIN_CONSTANT_P if (__builtin_constant_p(*expected) && - *expected <= PG_INT16_MAX && *expected >= PG_INT16_MIN) + (int64) *expected <= PG_INT16_MAX && + (int64) *expected >= PG_INT16_MIN) __asm__ __volatile__( " sync \n" " ldarx %0,0,%5 \n" diff --git a/src/test/regress/regress.c b/src/test/regress/regress.c index 02397f2eb10..09bc42a8c0f 100644 --- a/src/test/regress/regress.c +++ b/src/test/regress/regress.c @@ -720,6 +720,14 @@ test_atomic_uint32(void) EXPECT_EQ_U32(pg_atomic_read_u32(&var), (uint32) INT_MAX + 1); EXPECT_EQ_U32(pg_atomic_sub_fetch_u32(&var, INT_MAX), 1); pg_atomic_sub_fetch_u32(&var, 1); + expected = PG_INT16_MAX; + EXPECT_TRUE(!pg_atomic_compare_exchange_u32(&var, &expected, 1)); + expected = PG_INT16_MAX + 1; + EXPECT_TRUE(!pg_atomic_compare_exchange_u32(&var, &expected, 1)); + expected = PG_INT16_MIN; + EXPECT_TRUE(!pg_atomic_compare_exchange_u32(&var, &expected, 1)); + expected = PG_INT16_MIN - 1; + EXPECT_TRUE(!pg_atomic_compare_exchange_u32(&var, &expected, 1)); /* fail exchange because of old expected */ expected = 10; |