RFR: 8290432: C2 compilation fails with assert(node->_last_del == _last) failed: must have deleted the edge just produced [v2]
Yi Yang
yyang at openjdk.org
Fri Aug 5 09:23:28 UTC 2022
> Hi, can I have a review for this patch? [JDK-8273585](https://bugs.openjdk.org/browse/JDK-8273585) recognized the form of `Phi->CastII->AddI` as additional parallel induction variables. In the following program:
>
> class Test {
> static int dontInline() {
> return 0;
> }
>
> static long test(int val, boolean b) {
> long ret = 0;
> long dArr[] = new long[100];
> for (int i = 15; 293 > i; ++i) {
> ret = val;
> int j = 1;
> while (++j < 6) {
> int k = (val--);
> for (long l = i; 1 > l; ) {
> if (k != 0) {
> ret += dontInline();
> }
> }
> if (b) {
> break;
> }
> }
> }
> return ret;
> }
>
> public static void main(String[] args) {
> for (int i = 0; i < 1000; i++) {
> test(0, false);
> }
> }
> }
>
> `val` is incorrectly matched with the new parallel IV form:
> 
> And C2 further replaces it with newly added nodes, which finally leads the crash:
> 
>
> I think we can add more constraints to the new form. The form of `Phi->CastXX->AddX` appears when using Preconditions.checkIndex, and it would be recognized as additional IV when 1) Phi != phi2, 2) CastXX is controlled by RangeCheck(to reflect changes in Preconditions checkindex intrinsic)
Yi Yang has updated the pull request incrementally with one additional commit since the last revision:
format
-------------
Changes:
- all: https://git.openjdk.org/jdk/pull/9695/files
- new: https://git.openjdk.org/jdk/pull/9695/files/e91c448e..c44af036
Webrevs:
- full: https://webrevs.openjdk.org/?repo=jdk&pr=9695&range=01
- incr: https://webrevs.openjdk.org/?repo=jdk&pr=9695&range=00-01
Stats: 15 lines in 1 file changed: 5 ins; 1 del; 9 mod
Patch: https://git.openjdk.org/jdk/pull/9695.diff
Fetch: git fetch https://git.openjdk.org/jdk pull/9695/head:pull/9695
PR: https://git.openjdk.org/jdk/pull/9695
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