>>> Ingo Molnar <[EMAIL PROTECTED]> 17.12.07 14:26 >>> > >* Jan Beulich <[EMAIL PROTECTED]> wrote: > >> This generally allows better code to be generated, since the zero- >> extension during 32-bit operations comes for free (needed when the >> result is used as array index or similar), whereas sign extension must >> be done explicitly and frequently requires a one byte larger >> instruction due to the necessary rex64 prefix. > >good catch! Applied your patch to x86.git - queued it up for v2.6.25. I >bet there are tons of other instances where we use signed instead of >unsigned and get worse code generation.
Yes, definitely. This patch was kind of a testing one whether this is a welcome change. As it appears to be, I'll probably produce more as I run into respective cases. Jan -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
