[Bug tree-optimization/112723] Missed optimization for invariants 'c+c' when c += -2147483648 and c is a global variable

[pinskia at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=112723

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Severity|normal                      |enhancement
           Keywords|                            |missed-optimization, TREE

--- Comment #1 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
The argument case is only optimized at the RTL level:
Trying 8 -> 9:
    8: {r87:SI=r85:SI-0x80000000;clobber flags:CC;}
      REG_DEAD r85:SI
      REG_UNUSED flags:CC
    9: {r88:SI=r87:SI<<0x1;clobber flags:CC;}
      REG_DEAD r87:SI
      REG_UNUSED flags:CC
Successfully matched this instruction:
(parallel [
        (set (reg:SI 88)
            (ashift:SI (reg/v:SI 85 [ cD.2766 ])
                (const_int 1 [0x1])))
        (clobber (reg:CC 17 flags))
    ])