[Bug] TT(layer) cannot toggle

[willthong]

Describe the Bug

Setting TT(1) and TT(2). Momentary working fine. Toggle not functioning at all.

Relevant lines from config.h:

#define TAPPING_TOGGLE 2
#define TAPPING_TERM 200

I am on Arch Linux with avr-gcc 12.2.0-1 - I believe that might be relevant because of this closed issue. When I change OPT >= s to OPT >= 2 in qmk_firmware/builddefs/common_rules.mk, this issue is fixed but split keyboard functionality stops working.

Tagging @jypma and @kevinstadler who appear to have unresolved problems from the other, closed issue.

Any suggestions would be hugely appreciated!

Keyboard Used

redox

Link to product page (if applicable)

No response

Operating System

Arch Linux

qmk doctor Output

No response

Is AutoHotKey / Karabiner installed

• [ ] AutoHotKey (Windows)
• [ ] Karabiner (macOS)

Other keyboard-related software installed

No response

Additional Context

No response

[drashna]

Do you have LTO enabled, by chance?

[willthong]

I've tried with both LTO enabled and disabled. When enabled, TT acts like a hold toggle instead, even though I have #define TAPPING_TOGGLE 2 in my config.h.

[getreuer]

The related thread notes that changing avr-gcc version and/or optimization level appear to be workarounds, with suggestions that the root cause is "an optimization related bug." OTOH, a common reason of course for optimization bugs is that the code has undefined behavior, not necessarily that the compiler is wrong. So we should check.

There's a unit test tests/basic/test_action_layer.cpp that exercises TT keys. I'd like to try running it with Valgrind or ASan. I know I can run the test with make test:basic, but I don't follow the Makefiles enough to see how that works.

Does anyone know how to get a test executable or build a test with different options?