Request for reviews .03 (L): 6814842: Load shortening optimizations

[Vladimir Kozlov]

Christian,

in immL13m7() it should be <=

(-4096L <= (n->get_long() + 7L))
          ^

Can you explain how indOffset13m7 memory reference is generated
when offset does not fit into 13 bits? I did not find the explanation
in this thread.

For example:

+   format %{ "LDSB   $mem+1,$dst\t! short -> byte" %}
+   ins_encode %{
+     __ ldsb($mem$$Address, $dst$$Register, 1);
+   %}

Let mem.disp == -4100 (so that -4100+7 > -4096) and with ldsb(mem, reg, 1)
you will get mem.disp == -4099 which does not fit into 13 bits.

Thanks,
Vladimir

Tom Rodriguez wrote:
> looks good.
> 
> tom
> 
> On May 12, 2009, at 3:02 AM, Christian Thalinger wrote:
> 
>> On Mon, 2009-05-11 at 13:38 -0700, Tom Rodriguez wrote:
>>> I don't think the assert in formssel.cpp is needed because it
>>> replicates the logic in this test that guards enabling cisc spill.
>>> I'd given that to you originally before I fully realized what was
>>> going wrong.
>>
>> I removed the assert.
>>
>>>
>>> 1127     if( def_oper == NameList::Not_in_list && instr->num_opnds()
>>> == num_opnds()) {
>>>
>>> in sparc.ad you use simm13 instead of 13 bit in the comments since
>>> that's the sparc terminology.
>>
>> I changed the ones I added, the others are just copied.
>>
>> http://cr.openjdk.java.net/~twisti/6814842/webrev.03/
>>
>> -- Christian
>>
>