Fixed uint overflow in floorf for negative exponents #153
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m1el
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Thanks for the PR @m1el and sorry for the delay! Are you still interested in landing this? If so mind including a test that exercises the overflow? Other than that I think this looks good to me |
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Ah I went ahead and pushed up a test for this mentioned in the OP, and looks like tests are still passing, so merging! Again sorry for the delay but thank you for the PR! |
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floorfhas a bug in extracting the exponent from bits, where intermediate calculation results areu32, but can go negative for negative exponents.The test case is very simple: calling
libm::floorf(0.5)in debug mode will panic with the following message:'attempt to subtract with overflow', <path>/libm/src/math/floorf.rs:6:13I took a quick look at other similar functions and couldn't find problems. It would be nice to run tests in debug mode to check if there are any other places that cause similar underflows.