[Bug rtl-optimization/120182] Incorrect code with -O3 and constant addresses

[rguenth at gcc dot gnu.org via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=120182

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
     Ever confirmed|0                           |1
   Last reconfirmed|                            |2025-05-09
          Component|tree-optimization           |rtl-optimization
             Status|UNCONFIRMED                 |NEW

--- Comment #6 from Richard Biener <rguenth at gcc dot gnu.org> ---
It looks like an rtl optimization issue:

        call    mmap@PLT
        cmpq    $2654208, %rax
        jne     .L2
        movb    $0, 2654208
        movq    2654208, %rax
        testq   %rax, %rax
        je      .L3
        movq    $256, (%rax)
.L3:
        movq    $256, 2654208
        movb    $0, 2654208
        movq    2654208, %rax
        testq   %rax, %rax
        je      .L4
        movq    $256, (%rax)
.L4:
        movq    $256, 2654208
        movb    $0, 2654208
        movb    $0, 2654209
        movb    $0, 2654210

so all the zeroing besides the first byte is sunk somehow.