[Bug target/36557] -m32 -mpowerpc64 produces better code than -m64 for a!=0

bergner at gcc dot gnu.org gcc-bugzilla@gcc.gnu.org
Tue Mar 5 00:28:10 GMT 2024


https://gcc.gnu.org/bugzilla/show_bug.cgi?id=36557

Peter Bergner <bergner at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|NEW                         |RESOLVED
                 CC|                            |bergner at gcc dot gnu.org
         Resolution|---                         |FIXED

--- Comment #5 from Peter Bergner <bergner at gcc dot gnu.org> ---
(In reply to Segher Boessenkool from comment #4)
> We now do
> 
>         cntlzw 3,3
>         srwi 3,3,5
>         xori 3,3,0x1
>         blr
> 
> which is still not optimal (and not what -m32 / -m32 -mpowerpc64 do).

My GCC 10 and later compiles show we now generate:

        addic 9,3,-1
        subfe 3,9,3
        blr

Marking as FIXED.


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