On 11/20/2012 11:24 AM, Richard Henderson wrote:
> On 11/20/2012 09:29 AM, Richard Sandiford wrote:
>> Gah. How about this patch, currently bootstrapping on x86_64-linux-gnu
>> as a sanity check? The last instance seems glaringly obvious in
>> hindsight :-(
>>
>> Richard
>>
>>
>> gcc/
>> * expmed.c (store_bit_field_1): Use adjust_bitfield_address_size
>> rather than adjust_bitfield_address to change the mode of a reference.
>> (extract_bit_field_1): Likewise.
>
> That patch does fix my ICE.
>
> It looks all good, too. As you say, glaringly obvious even. ;-)
One further point -- get_best_mem_extraction_insn does not work for
the traditional 'extv' patterns that only accept memories. In
particular, the QImode memory in the extv pattern never matches up
at the beginning of get_traditional_extraction_insn, so that first
"if (mode != struct_mode) return false;" always triggers.
I audited the existing extv patterns and the affected targets are
alpha, sh, and vax. All of the others implement extv on registers,
which appears to work. Test case:
struct S { long y __attribute__((packed)); };
long g(struct S *s) { return s->y; }
Before:
ldq_u $0,0($16)
ldq_u $1,7($16)
extql $0,$16,$0
extqh $1,$16,$16
bis $0,$16,$0
After:
ldbu $5,1($16)
ldbu $8,0($16)
ldbu $7,2($16)
ldbu $6,3($16)
ldbu $4,4($16)
ldbu $3,5($16)
sll $5,8,$5
ldbu $2,6($16)
ldbu $1,7($16)
sll $7,16,$7
sll $6,24,$6
bis $5,$8,$5
sll $4,32,$4
sll $3,40,$3
bis $7,$5,$5
sll $2,48,$2
sll $1,56,$1
bis $6,$5,$0
bis $4,$0,$0
bis $3,$0,$0
bis $2,$0,$0
bis $1,$0,$0
I suppose the question is: with only 3 affected targets, is it more
trouble fiddling the somewhat confused "traditional" path, or to
just go ahead and update the backends?
r~
