On Tue, May 17, 2016 at 12:17 PM, Uros Bizjak <ubiz...@gmail.com> wrote:
> Hello!
>
>> This bug is introduced by my commit r236181 where the inner rtx of
>> SUBREG haven't been checked while it should as "in_class_p" only
>> works with REG, and SUBREG_REG is actually not always REG. If REG_P
>> check failed, then we should fall back to normal code patch. The
>> following simple testcase for x86 can reproduce this bug.
>
>> diff --git a/gcc/lra-constraints.c b/gcc/lra-constraints.c
>> index 56ab5b4..e4e6c8c 100644
>> --- a/gcc/lra-constraints.c
>> +++ b/gcc/lra-constraints.c
>> @@ -1317,7 +1317,8 @@ process_addr_reg (rtx *loc, bool check_only_p,
>> rtx_insn **before, rtx_insn **aft
>> register, and this normally will be a subreg which should be reloaded
>> as a whole. This is particularly likely to be triggered when
>> -fno-split-wide-types specified. */
>>- if (in_class_p (reg, cl, &new_class)
>>+ if (!REG_P (reg)
>>+ || in_class_p (reg, cl, &new_class)
>> || GET_MODE_SIZE (mode) <= GET_MODE_SIZE (ptr_mode))
>> loc = &SUBREG_REG (*loc);
>
> Why not check SUBREG_P instead of !REG_P?
Or, alternatively:
if ((REG_P && !in_class_p (reg, ...))
|| GET_MODE_SIZE ...)
Which is IMO much more readable.
Uros.
