RFR: 8322694: C1: Handle Constant and IfOp in NullCheckEliminator [v2]

[Dean Long]

On Wed, 3 Jan 2024 13:37:21 GMT, Denghui Dong <ddong at openjdk.org> wrote:

>> This patch added the support for Constant and IfOn in NullCheckEliminator to eliminate more null check.
>> 
>> testing: tier 1-4 no extra test failure
>
> Denghui Dong has updated the pull request incrementally with one additional commit since the last revision:
> 
>   update

src/hotspot/share/c1/c1_Optimizer.cpp line 1218:

> 1216: 
> 1217: void NullCheckEliminator::handle_IfOp(IfOp *x) {
> 1218:   if (x->type()->is_object() && set_contains(x->tval()) && set_contains(x->fval())) {

What if x->tval() or x->fval() are also IfOp's?  Does NullCheckEliminator visit those depth-first?

-------------

PR Review Comment: https://git.openjdk.org/jdk/pull/17191#discussion_r1480639905