[Bug tree-optimization/108357] New: Dead Code Elimination Regression at -O2 (trunk vs. 12.2.0)

["yann at ywg dot ch" <gcc-bugzilla@gcc.gnu.org>]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=108357

            Bug ID: 108357
           Summary: Dead Code Elimination Regression at -O2 (trunk vs.
                    12.2.0)
           Product: gcc
           Version: 13.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: tree-optimization
          Assignee: unassigned at gcc dot gnu.org
          Reporter: yann at ywg dot ch
  Target Milestone: ---

Created attachment 54232
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=54232&action=edit
presented code as file

cat case.c #411
static char b;
static unsigned c;
void foo();
short(a)(short d, short e) { return d * e; }
static short f(short d) {
  b = 0;
  if ((d && 0 >= c < d) ^ d)
    ;
  else
    foo();
  return d;
}
int main() {
  short g = a(5, b ^ 9854);
  f(g);
}

`gcc-cb93c5f8008b95743b741d6f1842f9be50c6985c (trunk) -O2` can not eliminate
`foo` but `gcc-releases/gcc-12.2.0 -O2` can.

`gcc-cb93c5f8008b95743b741d6f1842f9be50c6985c (trunk) -O2 -S -o /dev/stdout
case.c`
--------- OUTPUT ---------
main:
.LFB2:
        .cfi_startproc
        movsbw  b(%rip), %ax
        movb    $0, b(%rip)
        xorw    $9854, %ax
        leal    (%rax,%rax,4), %eax
        cmpw    $1, %ax
        movswl  %ax, %edx
        setg    %al
        movzbl  %al, %eax
        cmpl    %eax, %edx
        je      .L9
        xorl    %eax, %eax
        ret
.L9:
        pushq   %rax
        .cfi_def_cfa_offset 16
        xorl    %eax, %eax
        call    foo
        xorl    %eax, %eax
        popq    %rdx
        .cfi_def_cfa_offset 8
        ret
---------- END OUTPUT ---------


`gcc-releases/gcc-12.2.0 -O2 -S -o /dev/stdout case.c`
--------- OUTPUT ---------
main:
.LFB2:
        .cfi_startproc
        movb    $0, b(%rip)
        xorl    %eax, %eax
        ret
---------- END OUTPUT ---------


Bisects to:
https://gcc.gnu.org/git/?p=gcc.git;a=commit;h=2dc5d6b1e7ec8822f5bd78761962ca2c85d4a2b4