For MSP430, the folding of identical functions marked with the "interrupt" attribute by -fipa-icf-functions results in wrong code being generated. Interrupts have different calling conventions than regular functions, so inserting a CALL from one identical interrupt to another is not correct and will result in stack corruption.
I imagine there are other targets that also have different calling conventions for interrupt functions compared to regular functions, and so folding them would be undesirable. Therefore, I would appreciate some feedback as to whether it would be welcomed to fix this in a generic way or if I should just keep it MSP430 specific. 1. MSP430 specific Add the "no_icf" attribute to functions marked with the "interrupt" attribute when processing them in the backend. 2. Target Hook Add a DEFHOOKPOD (e.g. TARGET_NO_INTERRUPT_ICF) which controls whether ICF is disabled for functions with the interrupt attribute (in gcc/ipa-icf.c, where "no_icf" attribute is processed). 3. Always on Same as 2. but without the hook implementation - just check for the interrupt attribute and disable ICF if it is present. I'm personally leaning towards option 2, target hook, since other targets may benefit from this. Thanks, Jozef
