8371528: C2: disable VerifyIterativeGVN Identity verification for ConvF2L etc

[eme64]

JDK-8371523 Found multiple fuzzer failures Identity optimizations in:

ConvD2L
ConvF2I
ConvF2L
ConvI2F

Example:

< Missed Identity optimization:
< Old node:
< dist dump
< ---------------------------------------------
< 1 2315 ConvL2D === _ 2120 [[ 2306 2314 2318 ]] #double !orig=845,[2608],[2215] !jvms: Test_2167::vMeth @ bci:128 (line 56)
< 0 2314 ConvD2L === _ 2315 [[ 2313 1052 845 ]] #long !orig=1074 !jvms: Test_2167::vMeth @ bci:204 (line 65)
< New node:
< dist dump
< ---------------------------------------------
< 1 2121 ConvL2D === _ 2123 [[ 2112 2120 2124 ]] #double !orig=845,[2608],[2215] !jvms: Test_2167::vMeth @ bci:128 (line 56)
< 0 2120 ConvD2L === _ 2121 [[ 2119 2315 2316 2667 ]] #long !orig=1074 !jvms: Test_2167::vMeth @ bci:204 (line 65)

We want to quickly silence the issue, and so we just disable verification here.
There is already a patch out as a fix for at least some of the related issues, though it is not clear to me that it covers cases like ConvF2L: #27900

We can fix the issues and attach reproducers in a follow-up fix.

---

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Issue

• JDK-8371528: C2: disable VerifyIterativeGVN Identity verification for ConvF2L etc (Sub-task - P4) ⚠️ Issue is not open.

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[JnRouvignac]

s/coment/comment/

[eme64]

This is no longer necessary.

/close

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