RFR: 8307683: Loop Predication is wrongly applied to non-RangeCheckNodes without a LoadRangeNode [v2]

[Christian Hagedorn]

On Fri, 26 May 2023 08:26:27 GMT, Roland Westrelin <roland at openjdk.org> wrote:

>> Christian Hagedorn has updated the pull request incrementally with two additional commits since the last revision:
>> 
>>  - fix assertion
>>  - new fix with bailout for "if iv <u limit then trap"
>
> src/hotspot/share/opto/loopPredicate.cpp line 856:
> 
>> 854:   if (range->Opcode() != Op_LoadRange) {
>> 855:     const TypeInteger* tinteger = phase->_igvn.type(range)->isa_integer(bt);
>> 856:     if (!iff->is_RangeCheck() || tinteger == nullptr || tinteger->empty() || tinteger->lo_as_long() < 0) {
> 
> Can the problem not happen with a LoadRange as second input? Couldn't the LoadRange constant fold and then the predicates could constant fold as well?

You're right. It's also a problem with a `LoadRange`, even if it does not constant fold.

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PR Review Comment: https://git.openjdk.org/jdk/pull/14156#discussion_r1207476796