On 2/4/21 11:11 AM, Paul Smith wrote:
The thing that really makes me want to punch my monitor is when a variable that contains critical info I need is optimized out. I don't know if it's just my code or what but it seems to happen to me A LOT that the info I need is only available in some register somewhere that I can't easily figure out how to retrieve, because the variable was optimized away.
Drives me crazy, too, but that's what optimization does. As I posted previously, I can't use -O0 and/or no optimization, so I long ago made my peace with it. I frequently have to sprinkle my code with:
#ifdef DEBUG volatile #endif unsigned some_variable; And of course that can cause problems when "some_variable" is passed to: void some_function(unsigned value) ... and passing a volatile unsigned instead is an error. So then it's: unsigned some_variable; some_variable = ... volatile unsigned copy_of_variable = some_variable; some_function(some_variable); ad nauseum. A real P.I.T.A.
I wonder if anyone has any thoughts about specific -fno-* settings I can add alongside -Og which will preserve either all, or most, or even just more, of the local variables rather than optimizing them away.
That would be nice (I'd need it with -O1) but I wouldn't hold my breath. It's likely way too deep in the many optimization passes to specifically turn it off for this use-case.
But I'd be pleasantly surprised to be informed otherwise.
