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Have pokeemerald use OFast, aapcs, and ftoplevel-reorder for MODERN by default #1945
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…y default The big question is: why make these changes? Let's take a look: OFast is a compiler flag that allows for some standard-breaking optimizations, mostly in the floating point category. Pokeemerald rarely uses floating points and where it does, it does not require extreme accuracy. In addition, OFast optimizes for speed, not space, of which there is always 32 MB of anyway. AAPCS is the ABI that supports arm7tdmi chips and up. It mostly mandated how functions start and end in order to interwork with thumb code. apcs-gnu was back when pokeemerald was still being decompiled. Finally, ftoplevel-reorder, it is not able to be disabled on clang, and without disabling top-level reordering, the game does not boot. Or rather, it doesn't boot because only one file, m4a.c, does not play nicely with the compiler, causing the game to crash when initializing the sound. For this reason, m4a.c gets its own exception in the Makefile. These changes should be beneficial to anyone compiling on MODERN and there does not seem to be any downsides. These changes were thoroughly tested for weeks on my end, to ensure no side effects happened. I hope you enjoy this! Signed-off-by: Arven
This file also relies on function ordering to operate properly, even though as of this moment, GCC happens to not do that.
We cannot assume that people are okay with non-standard floating point optimizations. If users believe that they need the extra speed, then they can enable it themselves. Also, I'm not fully sure on the history of
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@PikalaxALT says that |
I predict that this PR will rot because nobody here knows enough about modern gcc stuff to accurately determine whether these changes will break anything. |
I was genuinely interested in this, partly at least because About About |
The big question is: why make these changes?
Let's take a look:
OFast is a compiler flag that allows for some standard-breaking optimizations, mostly in the floating point category. Pokeemerald rarely uses floating points and where it does, it does not require extreme accuracy. In addition, OFast optimizes for speed, not space, of which there is always 32 MB of anyway.
AAPCS is the ABI that supports arm7tdmi chips and up. It mostly mandated how functions start and end in order to interwork with thumb code. apcs-gnu was back when pokeemerald was still being decompiled.
Finally, ftoplevel-reorder, it is not able to be disabled on clang, and without disabling top-level reordering, the game does not boot. Or rather, it doesn't boot because only one file, m4a.c, does not play nicely with the compiler, causing the game to crash when initializing the sound. For this reason, m4a.c gets its own exception in the Makefile.
These changes should be beneficial to anyone compiling on MODERN and there does not seem to be any downsides. These changes were thoroughly tested for weeks on my end, to ensure no side effects happened. I hope you enjoy this!
Signed-off-by: Arven