[Bug c/92118] New: warning with [-Wmaybe-uninitialized] in -O1

[tangyixuan at mail dot dlut.edu.cn]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=92118

            Bug ID: 92118
           Summary: warning with [-Wmaybe-uninitialized] in -O1
           Product: gcc
           Version: 10.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c
          Assignee: unassigned at gcc dot gnu.org
          Reporter: tangyixuan at mail dot dlut.edu.cn
  Target Milestone: ---

[-Wmaybe-uninitialized] should be independent of optimization levels
(-O0/O1/../O3) or may be a spurious Warnings on -O1:

$ cat s.c
  int main()
  {
    int i;
    for(;i<5;i++){
    }
    return 0;
  }

$ gcc-trunk -O1 -Wmaybe-uninitialized s.c

s.c: In function ‘main’:
s.c:4:13: warning: ‘i’ may be used uninitialized in this function
[-Wmaybe-uninitialized]
   for(;i<5;i++){
                 ~^~

gcc version 10.0.0 20190913 (experimental) (GCC)
target: Ubuntu 4.8.5-4ubuntu8~14.04.2

Since the default value of ‘i’ is 0, there is no warning with -O0/O2/O3.