[Bug ipa/99373] New: [missed optimization] dead code not eliminated from short circuiting

["zhendong.su at inf dot ethz.ch" <gcc-bugzilla@gcc.gnu.org>]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=99373

            Bug ID: 99373
           Summary: [missed optimization] dead code not eliminated from
                    short circuiting
           Product: gcc
           Version: unknown
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: ipa
          Assignee: unassigned at gcc dot gnu.org
          Reporter: zhendong.su at inf dot ethz.ch
                CC: marxin at gcc dot gnu.org
  Target Milestone: ---

[538] % gcctk -v
Using built-in specs.
COLLECT_GCC=gcctk
COLLECT_LTO_WRAPPER=/local/suz-local/software/local/gcc-trunk/libexec/gcc/x86_64-pc-linux-gnu/11.0.1/lto-wrapper
Target: x86_64-pc-linux-gnu
Configured with: ../gcc-trunk/configure --disable-bootstrap
--prefix=/local/suz-local/software/local/gcc-trunk --enable-languages=c,c++
--disable-werror --enable-multilib --with-system-zlib
Thread model: posix
Supported LTO compression algorithms: zlib
gcc version 11.0.1 20210303 (experimental) [master revision
d97a92dca90:bc15d73426f:9b2084db9f9917eb9b19b1eb5ec03cdcb05f349e] (GCC) 
[539] % 
[539] % gcctk -O3 -S -o small.s small.c
[540] % 
[540] % cat small.c
extern void foo();

struct a {
  int b;
  long c;
} g;
static int d = 1;
int e, *f, *h;
long *i;

static long j() {
  struct a k;
  struct a *m = &g;
  struct a **n[] = {&m};
  long **l = 0;
  int o[42];
  foo();
  int p[] = {1, 1, 1, 1, 1, 1, 1, 1, 1, 1};
  int *d[] = {&p[3]};
  i = &k.c;
  long ***a[] = {&l};
  int b[5];
  f = &b[3];
  if (e)
    while (1)
      h = &o[7];
  return 0;
}
int main() {
  d || j();
  return 0;
}
[541] % 
[541] % cat small.s
        .file   "small.c"
        .text
        .p2align 4
        .type   j.isra.0, @function
j.isra.0:
.LFB2:
        .cfi_startproc
        subq    $56, %rsp
        .cfi_def_cfa_offset 64
        xorl    %eax, %eax
        call    foo
        leaq    8(%rsp), %rax
        movq    %rax, i(%rip)
        leaq    28(%rsp), %rax
        movq    %rax, f(%rip)
        movl    e(%rip), %eax
        testl   %eax, %eax
        jne     .L3
        addq    $56, %rsp
        .cfi_remember_state
        .cfi_def_cfa_offset 8
        ret
.L3:
        .cfi_restore_state
        jmp     .L3
        .cfi_endproc
.LFE2:
        .size   j.isra.0, .-j.isra.0
        .section        .text.startup,"ax",@progbits
        .p2align 4
        .globl  main
        .type   main, @function
main:
.LFB1:
        .cfi_startproc
        xorl    %eax, %eax
        ret
        .cfi_endproc
.LFE1:
        .size   main, .-main
        .globl  i
        .bss
        .align 8
        .type   i, @object
        .size   i, 8
i:
        .zero   8
        .globl  h
        .align 8
        .type   h, @object
        .size   h, 8
h:
        .zero   8
        .globl  f
        .align 8
        .type   f, @object
        .size   f, 8
f:
        .zero   8
        .globl  e
        .align 4
        .type   e, @object
        .size   e, 4
e:
        .zero   4
        .globl  g
        .align 16
        .type   g, @object
        .size   g, 16
g:
        .zero   16
        .ident  "GCC: (GNU) 11.0.1 20210303 (experimental) [master revision
d97a92dca90:bc15d73426f:9b2084db9f9917eb9b19b1eb5ec03cdcb05f349e]"
        .section        .note.GNU-stack,"",@progbits