On Sun, Aug 21, 2011 at 1:58 AM, Richard Henderson <r...@redhat.com> wrote:
> On 08/20/2011 03:03 PM, H.J. Lu wrote:
>> On Sat, Aug 20, 2011 at 3:02 PM, H.J. Lu <hjl.to...@gmail.com> wrote:
>>>> You can do better than this, and avoid the %M %N specifiers.
>>>> The outputs are truly independent and do not need to be a pair.
>>>>
>>>
>>> Since RA use register pairs for TImode/DImode, should requiring
>>> TI/DI registers in pairs generate better does?
>> ^^^^^^ codes.
>>
>> Without register pairs, we are generating very strange codes.
>>
>
> We ought to be making better use of the lower-subregs pass.
> Representing independent outputs when possible enables that.
>
> Admittedly, the i386 port needs more attention to really make
> this happen properly. But we don't need to make things even
> worse in the meantime.
I will investigate this.
BTW: Latest patch has a small error. Insn mnemonic in following
pattern should be "mult" instead of "imult", so the correct version
reads:
+(define_insn "*umul<mode><dwi>3_1"
+ [(set (match_operand:<DWI> 0 "register_operand" "=A,r")
+ (mult:<DWI>
+ (zero_extend:<DWI>
+ (match_operand:DWIH 1 "nonimmediate_operand" "%0,d"))
+ (zero_extend:<DWI>
+ (match_operand:DWIH 2 "nonimmediate_operand" "rm,rm"))))
+ (clobber (reg:CC FLAGS_REG))]
+ "!(MEM_P (operands[1]) && MEM_P (operands[2]))"
+ "@
+ mul{<imodesuffix>}\t%2
+ #"
Uros.
