https://gcc.gnu.org/bugzilla/show_bug.cgi?id=90979
Bug ID: 90979
Summary: UBSan breaks OpenMP atomics
Product: gcc
Version: 9.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: sanitizer
Assignee: unassigned at gcc dot gnu.org
Reporter: jakub at gcc dot gnu.org
CC: dodji at gcc dot gnu.org, dvyukov at gcc dot gnu.org,
jakub at gcc dot gnu.org, kcc at gcc dot gnu.org, marxin at
gcc dot gnu.org
Target Milestone: ---
The following testcase with -O2 -fopenmp
-fsanitize=undefined,float-divide-by-zero actually doesn't end with the
expected atomic operations:
void
foo (int *p, int x)
{
#pragma omp atomic
*p = *p / x;
}
void
bar (float *p, float x)
{
#pragma omp atomic
*p = *p / x;
}
void
baz (int *p, int x)
{
#pragma omp atomic
*p <<= x;
}
void
qux (int *p, int x)
{
#pragma omp atomic
*p = *p >> x;
}
I bet we'll need to temporarily disable at least SANITIZE_SHIFT_BASE |
SANITIZE_SHIFT_EXPONENT | SANITIZE_DIVIDE | SANITIZE_FLOAT_DIVIDE from
flag_sanitize during the #pragma omp atomic parsing and then then readd that
sanitization later or be able to pattern match what that sanitization creates
later. Unfortunately, the first possibility would turn it off even for parsing
of subexpressions.
