RFR: 8338442: AArch64: Clean up IndOffXX type and let legitimize_address() fix out-of-range operands [v2]

[Fei Gao]

On Fri, 8 Dec 2023 02:13:02 GMT, Dean Long <dlong at openjdk.org> wrote:

>> I think this patch is excessive for the problem and introduces a lot of code dupiication. Maybe it would be simpler, smaller, and faster to check for what we need:
>> 
>> 
>> diff --git a/src/hotspot/cpu/aarch64/aarch64.ad b/src/hotspot/cpu/aarch64/aarch64.ad
>> index 233f9b6af7c..ea842912ce9 100644
>> --- a/src/hotspot/cpu/aarch64/aarch64.ad
>> +++ b/src/hotspot/cpu/aarch64/aarch64.ad
>> @@ -5911,7 +5911,8 @@ operand indIndexN(iRegN reg, iRegL lreg)
>>  
>>  operand indOffIN(iRegN reg, immIOffset off)
>>  %{
>> -  predicate(CompressedOops::shift() == 0);
>> +  predicate(CompressedOops::shift() == 0
>> +            && Address::offset_ok_for_immed(n->in(3)->find_int_con(min_jint), exact_log2(sizeof(jint))));
>>    constraint(ALLOC_IN_RC(ptr_reg));
>>    match(AddP (DecodeN reg) off);
>>    op_cost(0);
>> @@ -5926,7 +5927,8 @@ operand indOffIN(iRegN reg, immIOffset off)
>>  
>>  operand indOffLN(iRegN reg, immLoffset off)
>>  %{
>> -  predicate(CompressedOops::shift() == 0);
>> +  predicate(CompressedOops::shift() == 0
>> +            && Address::offset_ok_for_immed(n->in(3)->find_long_con(min_jint), exact_log2(sizeof(jlong))));
>>    constraint(ALLOC_IN_RC(ptr_reg));
>>    match(AddP (DecodeN reg) off);
>>    op_cost(0);
>
> @theRealAph , your patch only works if when `indOffIN` is used in `memory4` and `indOffLN` is used in `memory8`, right?
> Introducing new operands like `indOffIN4` is consistent with how the code currently works with `indOffI4`.  In fact I think the new `indOffIN<size>` could be folded into the existing `indOffI<size>`  by using multiple `match` lines and a better predicate.

@dean-long thanks for your approval!

Thanks for your suggestions @eme64 @TobiHartmann. Updated with a new RFE :)

I'll integrate it.

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PR Comment: https://git.openjdk.org/jdk/pull/16991#issuecomment-2291501106