| Message ID | CAGWvny=-baLJY+zA0fVoUN_H45Mje4sGK8DU5T11cOpNe=Tugw@mail.gmail.com |
|---|---|
| State | New |
| Headers | show |
> + a += v >> (sizeof (intptr_t) * CHAR_BIT / 2); > + b += v & (((intptr_t) 1 << (sizeof (intptr_t) * CHAR_BIT / 2)) - 1); It would be far easier to read if you added a BITS_PER_POINTER define somewhere. Other than that it looks good to me, but I cannot approve. -Andi
On Sat, May 4, 2013 at 1:41 PM, David Edelsohn <dje.gcc@gmail.com> wrote: > 2013-05-04 David Edelsohn <dje.gcc@gmail.com> > Peter Bergner <bergner@vnet.ibm.com> > Segher Boessenkool <segher@kernel.crashing.org> > Jakub Jelinek <jakub@redhat.com> This is OK (the actual ChangeLog entry was omitted). Thanks. Ian
Index: hashtab.c =================================================================== --- hashtab.c (revision 198587) +++ hashtab.c (working copy) @@ -990,17 +990,8 @@ unsigned a, b, c; a = b = 0x9e3779b9; - if (sizeof (intptr_t) == 4) - { - /* Mix as 16bit for now */ - a += v >> 16; - b += v & 0xffff; - } - else - { - a += v >> 32; - b += v & 0xffffffff; - } + a += v >> (sizeof (intptr_t) * CHAR_BIT / 2); + b += v & (((intptr_t) 1 << (sizeof (intptr_t) * CHAR_BIT / 2)) - 1); c = 0x42135234; mix (a, b, c); return c;
The revised version of hash_pointer() produces warnings when compiled on a 32 bit host because it shift a 32 bit variable by 32 bits. + intptr_t v = (intptr_t)p; ... + b += v & 0xffffffff; The code is not executed when intptr_t is 32 bits, but it still is present in the function, causing a warning. The appended, revised implementation was designed by a blue ribbon commission. Bootstrapped on powerpc-ibm-aix7.1.0.0. Okay for trunk? 2013-05-04 David Edelsohn <dje.gcc@gmail.com> Peter Bergner <bergner@vnet.ibm.com> Segher Boessenkool <segher@kernel.crashing.org> Jakub Jelinek <jakub@redhat.com>