Going Faster by Duplicating Code

Re:Going Faster by Duplicating Code by wycy on Wednesday October 11, 2023 @07:41AM (#37843261)

Using -O3 was resulting in correctness problems in my work codebase in the past. Nowadays the compiler (ifort) crashes when using -O3 for some reason.

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Re:Going Faster by Duplicating Code by qweqwe14 on Wednesday October 11, 2023 @08:35AM (#37843634)

> Using -O3 was resulting in correctness problems

Likely because your codebase had UB in it that didn't show itself until a certain optimization level. The solution is to fix all instances of UB. See my comment above.

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Re:Going Faster by Duplicating Code by wycy on Thursday October 12, 2023 @07:56AM (#37856000)

I believe in our case it was a compiler bug, because it only happened for a few versions of ifort and was eventually fixed. But it scared us off from using -O3.

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