gh-93678: apply remove_redundant_jumps in optimize_cfg

[iritkatriel]

Fixes#93678.

Apply remove_redundant_jumps in optimise_cfg because it belongs there. Later in move_cold_blocks_to_end, we may need to apply it again.

Added an assertion just before assembly stage that there are no redundant jumps.

Also tidy up an unrelated error handling issue I spotted.

• Issue: Direct unit tests for compiler optimisations #93678

[markshannon]

One minor refactoring suggestion.
Otherwise, looks good.

[bedevere-bot]

🤖 New build scheduled with the buildbot fleet by @iritkatriel for commit d0ffa15 🤖

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[iritkatriel]

One minor refactoring suggestion.
Otherwise, looks good.

So the way it is now, the Gentoo Non-Debug build fails because no_redundant_jumps is not defined:

Python/compile.c:8647:12: error: implicit declaration of function ‘no_redundant_jumps’; did you mean ‘remove_redundant_jumps’? [-Werror=implicit-function-declaration]
8647 | assert(no_redundant_jumps(g));
| ^~~~~~~~~~~~~~~~~~

If I remove the #ifdef Py_DEBUG from the definition of no_redundant_jumps then I get warnings about it not being used on my local build.

[iritkatriel]

@markshannon how about this version?

[bedevere-bot]

🤖 New build scheduled with the buildbot fleet by @iritkatriel for commit e47688a 🤖

If you want to schedule another build, you need to add the ":hammer: test-with-buildbots" label again.

[iritkatriel]

@markshannon how about this version?

Buildbots are fine with it.

[markshannon]

I'd rather fix the underlying issue.
Why does the Gentoo Non-Debug build have asserts on? That doesn't sound like non-debug to me.

[markshannon]

Changing the #ifdef Py_DEBUG to #ifndef NDEBUG should work, but I thought #ifdef Py_DEBUG implied #ifndef NDEBUG ande vice-versa.

Am I wrong, or the gentoo non-debug build mis-configured somehow?

[gpshead]

NDEBUG can always be used independent of Py_DEBUG. (ex: we regularly build Python and the world -UNDEBUG mode at work in the default build that people test against)

[gpshead]

as for how it happened in this case, CFLAGS adds -UNDEBUG in https://github.com/python/buildmaster-config/blob/0669211daf34f86e879868364efe15683da0e069/master/custom/factories.py#L277

[bedevere-bot]

🤖 New build scheduled with the buildbot fleet by @iritkatriel for commit 065d97d 🤖

If you want to schedule another build, you need to add the ":hammer: test-with-buildbots" label again.