[Bug rtl-optimization/116560] RISC-V : rv32 code optimization , big code difference between 8/9.x and 10.x

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

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=116560

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Target|                            |riscv, mips
          Component|target                      |rtl-optimization
             Status|UNCONFIRMED                 |NEW
           Keywords|                            |missed-optimization
     Ever confirmed|0                           |1
   Last reconfirmed|                            |2024-09-01

--- Comment #1 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
Same bad code can be produced by:

```
typedef unsigned short type1 __attribute__((may_alias, aligned(1)));
unsigned char test_swap1(unsigned char *ptr, unsigned *res)
{
  type1 *t = (type1 *)ptr;

    unsigned short temp=*t;
    temp = __builtin_bswap16(temp);
    *res=temp;
    if (temp==0) return 1;
    return 0;
}
```

The problem only happens on strict aligned targets (MIPS, SPARC, RISCV) which
don't have a 16 byte swap.