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The JIT's "pure" _BINARY_OP evaluation produces UB (and incorrect results) #136183
Description
Crash report
This code snippet crashes when the JIT is enabled:
for _ in range(4096):
2 ** 65I believe this is caused by GH-132733. Specifically, the abstract interpreter generator "thinks" that the operation itself can escape, and spills res to the stack before it has been defined:
cpython/Python/optimizer_cases.c.h
Line 2726 in 93809a9
It also never writes the actual result to the stack once it has been computed, leaving the garbage value in its place.
The fix is probably to teach the code generator that nothing using this "pure" constant evaluation mechanism can escape.
Activity
gh-136183: Deal with escapes in JIT optimizer's constant evaluator (G…
pythongh-136183: Deal with escapes in JIT optimizer's constant evalua…
pythongh-136183: Deal with escapes in JIT optimizer's constant evalua…
pythongh-136183: Deal with escapes in JIT optimizer's constant evalua…
pythongh-136183: Deal with escapes in JIT optimizer's constant evalua…
pythongh-136183: Deal with escapes in JIT optimizer's constant evalua…