On 01/05/2010 04:31 PM, Richard Henderson wrote:
A while ago Laurent pointed out that the setcc opcode emitted by
the setcond patch had unnecessary REX prefixes.
The existing P_REXB internal opcode flag unconditionally emits
the REX prefix. Technically it's not needed if the register in
question is %al, %bl, %cl, %dl.
I should perhaps mention that this patch doesn't help out all
that much. Only EBX is free for use by the code generator, so
more often than not we're using %bpl, which does require the
REX prefix.
r~
