[Bug tree-optimization/114318] New: Missing Optimization after multiple function calls

[Bug tree-optimization/114318] New: Missing Optimization after multiple function calls

[carnet at student dot ethz.ch]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=114318

            Bug ID: 114318
           Summary: Missing Optimization after multiple function calls
           Product: gcc
           Version: 14.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: tree-optimization
          Assignee: unassigned at gcc dot gnu.org
          Reporter: carnet at student dot ethz.ch
  Target Milestone: ---

GCC -O3 does not inline the function if there are more than two calls. This
also only happens in the main function. Changing the name of the main function
and/or reducing the number of function calls, enables the optimization.

https://godbolt.org/z/KM71WrYac

Source
int a, c, d;
int *b, *e;
static int *f() {
  int *g = &d;
  int **h = &b;
  *g = 1;
  *h = &c;
  if (*b)
    for (; d; d = d + 8)
      ;
  return &d;
}
int main() {
  f();
  f();
  f();
}

x86 -O3 Assembly:
f.part.0:
        movl    d(%rip), %eax
        testl   %eax, %eax
        je      .L1
        movl    $0, d(%rip)
.L1:
        ret
main:
        movl    $1, d(%rip)
        movl    c(%rip), %ecx
        testl   %ecx, %ecx
        je      .L5
        xorl    %eax, %eax
        call    f.part.0
.L5:
        movl    $1, d(%rip)
        movl    c(%rip), %edx
        testl   %edx, %edx
        je      .L6
        xorl    %eax, %eax
        call    f.part.0
.L6:
        movl    $1, d(%rip)
        movl    c(%rip), %eax
        movq    $c, b(%rip)
        testl   %eax, %eax
        je      .L7
        xorl    %eax, %eax
        call    f.part.0
.L7:
        xorl    %eax, %eax
        ret
e:
        .zero   8
b:
        .zero   8
d:
        .zero   4
c:
        .zero   4
a:
        .zero   4

[Bug tree-optimization/114318] Missing Optimization after multiple function calls

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=114318

Richard Biener <rguenth at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |RESOLVED
         Resolution|---                         |WONTFIX

--- Comment #1 from Richard Biener <rguenth at gcc dot gnu.org> ---
That's because main is cold.

[Bug tree-optimization/114318] Missing Optimization after multiple function calls

[pinskia at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=114318

--- Comment #2 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
(In reply to Richard Biener from comment #1)
> That's because main is cold.

Or rather known to be called once which causes the path to be considered cold
unless there is a loop.