[Bug rtl-optimization/114693] New: `expand` introduce redundant store facing logic expression

[Bug rtl-optimization/114693] New: `expand` introduce redundant store facing logic expression

[absoler at smail dot nju.edu.cn]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=114693

            Bug ID: 114693
           Summary: `expand` introduce redundant store facing logic
                    expression
           Product: gcc
           Version: 13.2.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: rtl-optimization
          Assignee: unassigned at gcc dot gnu.org
          Reporter: absoler at smail dot nju.edu.cn
  Target Milestone: ---

A simple case, regression from gcc-5
```
struct S{
    char  f0;
    int  f3;
} s;
int g, f;

void func_1() {
  int a = 0;
  s.f0 = 1 && ((3 > a) & g);
}
```
compiled with -O2 :

```
func_1():
  401340:       mov    0x10846(%rip),%eax        # 411b8c <g>
  401346:       mov    %al,0x10844(%rip)        # 411b90 <s>
  40134c:       andb   $0x1,0x1083d(%rip)        # 411b90 <s>
  401353:       retq  
```

it seems "1 && " interfere the compiler, after removing it the compiler
generates:
```
func_1():
  401340:       movzbl 0x10845(%rip),%eax        # 411b8c <g>
  401347:       and    $0x1,%eax
  40134a:       mov    %al,0x10840(%rip)        # 411b90 <s>
  401350:       retq   
```

[Bug target/114693] `expand` introduce redundant store facing logic expression

[pinskia at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=114693

Andrew Pinski <pinskia at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Target|                            |x86_64
          Component|rtl-optimization            |target

--- Comment #1 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
This is a target specific issue on how x86_64 backend patterns are done IIRC.

[Bug target/114693] `expand` introduce redundant store facing logic expression

[pinskia at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=114693

Andrew Pinski <pinskia at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
   Target Milestone|---                         |14.0
         Resolution|---                         |FIXED
           Keywords|                            |missed-optimization
             Status|UNCONFIRMED                 |RESOLVED

--- Comment #2 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
Actually this is fixed on the trunk.

This is what we got in GCC 13 and before:
  g.0_1 = g;
  _2 = (_Bool) g.0_1;
  _3 = (char) _2;
  s.f0 = _3;


But in GCC 14+ we get:
  g.0_1 = g;
  _2 = g.0_1 & 1;
  _3 = (char) _2;
  s.f0 = _3;


This was fixed by r14-6420-g85c5efcffed19c .