GH-118093: Add tier two support to several instructions #121884
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brandtbucher added performance brandtbucher requested review from Fidget-Spinner and markshannon as code owners 
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markshannon requested changes Jul 17, 2024
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One minor clarification needed, otherwise LGTM.
Regarding handling CALL_LIST_APPEND in tier 2:
Instead of asserting that the next instruction is POP_TOP and skipping it, we could emit a LOAD_CONST_BORROW None.
If the following instruction is not POP_TOP then then code is still correct. If there is a POP_TOP following, then optimizer will eliminate the LOAD; POP_TOP.
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| I have made the requested changes; please review again |
| Thanks for making the requested changes! @markshannon: please review the changes made to this pull request. |
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| JIT failures are unrelated: GH-121946 |
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This adds tier two support to all of the the trivial instructions that our stats indicate are causing traces to end (
CALL_LIST_APPEND,IMPORT_NAME,LOAD_NAME,BUILD_SET,SEND_GEN, andIMPORT_FROM). Some other, more complicated, instructions will come in their own PRs. It also turns_FOR_ITER_TIER_TWOfrom a deopting instruction into an exiting instruction, since we expect it to fail fairly often (since this represents normal control flow in the program).Perf is neutral. Stats have improved, as expected (4% fewer tier one instructions, 24% fewer too-short traces, 20% fewer optimization attempts, 7% fewer traces executed, 4% more traces created, and 4% more uops executed).