[Bug rtl-optimization/43473] hword size destination variable induces suboptimal code generation compared to full word size var

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

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=43473

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Keywords|                            |missed-optimization

--- Comment #3 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
The difference is.
for ma:
```
(insn 11 10 13 2 (set (reg:SI 122)
        (ior:SI (subreg:SI (reg:HI 119 [ a ]) 0)
            (const_int -16384 [0xffffffffffffc000]))) "/app/example.cpp":9:11
110 {*iorsi3_insn}
     (expr_list:REG_DEAD (reg:HI 119 [ a ])
        (nil)))
```

vs for mb:
```
(insn 9 8 10 2 (set (reg:SI 121 [ _3 ])
        (ior:SI (reg:SI 120 [ b ])
            (const_int 49152 [0xc000]))) "/app/example.cpp":16:22 110
{*iorsi3_insn}
     (expr_list:REG_DEAD (reg:SI 120 [ b ])
        (nil)))
```