https://gcc.gnu.org/bugzilla/show_bug.cgi?id=108845
Bug ID: 108845
Summary: Unnecessary signed integer overflow checks
Product: gcc
Version: unknown
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: sanitizer
Assignee: unassigned at gcc dot gnu.org
Reporter: qrzhang at gatech dot edu
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: ---
When compiled with "gcc -fsanitize=signed-integer-overflow -O3" (reproducible
on the latest trunk version), Gcc will produce ".UBSAN_CHECK_SUB" checks for
the following code.
=======
void printf();
void main() {
int a;
for (a = 0; a != -3; a--)
printf("%d\n", a);
}
========
I noticed that clang could indeed optimize this program to three printf() calls
with "-fsanitize=signed-integer-overflow -O3". Therefore, no overflow checks
are needed.
Is this behavior in GCC expected? Thanks!
