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| author |  Gael Guennebaud <g.gael@free.fr> | 2016-02-12 22:16:59 +0100 |
|---|---|---|
| committer | Gael Guennebaud <g.gael@free.fr> | 2016-02-12 22:16:59 +0100 |
| commit | 8e1f1ba6a6cf0580da6f8756562f94b6410d5e58 (patch) | |
| tree | 2f9c7a10a24298cd620e022affb9b20ac23ef948 /doc/UnalignedArrayAssert.dox | |
| parent | c8b4c4b48a41a1744c9ad7a888e2bcad23250904 (diff) | |
Import wiki's paragraph: "I disabled vectorization, but I'm still getting annoyed about alignment issues"
Diffstat (limited to 'doc/UnalignedArrayAssert.dox')
| -rw-r--r-- | doc/UnalignedArrayAssert.dox | 5 |
1 files changed, 4 insertions, 1 deletions
diff --git a/doc/UnalignedArrayAssert.dox b/doc/UnalignedArrayAssert.dox index 65ab16fb7..f0f84d25f 100644 --- a/doc/UnalignedArrayAssert.dox +++ b/doc/UnalignedArrayAssert.dox @@ -109,7 +109,10 @@ Two possibilities: 128-bit alignment code and thus preserves ABI compatibility, but completely disables vectorization.</li> </ul> -For more information, see <a href="http://eigen.tuxfamily.org/index.php?title=FAQ#I_disabled_vectorization.2C_but_I.27m_still_getting_annoyed_about_alignment_issues.21">this FAQ</a>. +If you want to know why defining EIGEN_DONT_VECTORIZE does not by itself disable 128-bit alignment and the assertion, here's the explanation: + +It doesn't disable the assertion, because otherwise code that runs fine without vectorization would suddenly crash when enabling vectorization. +It doesn't disable 128bit alignment, because that would mean that vectorized and non-vectorized code are not mutually ABI-compatible. This ABI compatibility is very important, even for people who develop only an in-house application, as for instance one may want to have in the same application a vectorized path and a non-vectorized path. */ |