On Fri, Jan 17, 2014 at 6:30 AM, Jakub Jelinek <ja...@redhat.com> wrote: > On Fri, Jan 17, 2014 at 06:19:37AM -0800, H.J. Lu wrote: >> ix86_split_lea_for_addr transforms a single LEA instruction into a series >> of MOV and ADD instructions. For >> >> lea 0x400(%eax, %ecx, 8), %edx >> >> we get >> >> mov %eax, %edx >> add %ecx, %edx >> add %ecx, %edx >> add %ecx, %edx >> add %ecx, %edx >> add %ecx, %edx >> add %ecx, %edx >> add %ecx, %edx >> add %ecx, %edx >> add $0x400, %edx > > Ugh, is that really want you want for silvermont, as opposed to (at least > if the output operand isn't equal to the base): > mov %ecx, %edx ! if base is equal to index this would go away > add %ecx, %edx > add %edx, %edx > add %edx, %edx > add %eax, %edx > add $0x400, %edx > ?
Wrong example. It should be lea 0x400(%edx, %ecx, 8), %edx we get add %ecx, %edx add %ecx, %edx add %ecx, %edx add %ecx, %edx add %ecx, %edx add %ecx, %edx add %ecx, %edx add %ecx, %edx add $0x400, %edx For lea 0x400(%eax, %ecx, 8), %edx we get mov %ecx, %edx shl $3, %edx add %eax, %edx add $0x400, %edx -- H.J.
