[Bug ipa/96211] New: Segmentation fault when using "-O2 -fno-dce -fno-tree-dce" but passing at -O2

[chenjunjie9208 at 163 dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=96211

            Bug ID: 96211
           Summary: Segmentation fault when using "-O2 -fno-dce
                    -fno-tree-dce" but passing at -O2
           Product: gcc
           Version: 11.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: ipa
          Assignee: unassigned at gcc dot gnu.org
          Reporter: chenjunjie9208 at 163 dot com
                CC: marxin at gcc dot gnu.org
  Target Milestone: ---

Hi,

I came across a bug recently. The following simplified code is miscompiled with
current gcc trunk using "-O2 -fno-dce -fno-tree-dce" on x86_64 GNU/Linux. It
will report "Segmentation fault (core dumped)". However, when using any
optimization levels (e.g., -O2, -O3), it does not have any problems. Looking
forward to your reply, Thanks!

$ gcc --version
gcc (GCC) 11.0.0 20200715 (experimental)
$
$ gcc -O2 -fno-dce -fno-tree-dce a.c; ./a.out
Segmentation fault (core dumped)
$ gcc -O3 -fno-dce -fno-tree-dce a.c; ./a.out
Segmentation fault (core dumped)
$ gcc -Os -fno-dce -fno-tree-dce a.c; ./a.out
Segmentation fault (core dumped)
$
$ gcc -O1 -fno-dce -fno-tree-dce a.c; ./a.out
$ gcc -O3 a.c; ./a.out
$ gcc -Os a.c; ./a.out
$ gcc -O2 a.c; ./a.out
$ gcc -O1 a.c; ./a.out
$ gcc -O0 a.c; ./a.out
$
---------------------------
static int *a();
void b() { a(); }
int *a(int c, int *d) { int e = 0 >= *d; }
int main() { b(); }