diff options
| author | Arnold Schwaighofer <aschwaighofer@apple.com> | 2014-03-12 23:23:44 +0000 |
|---|---|---|
| committer | Arnold Schwaighofer <aschwaighofer@apple.com> | 2014-03-12 23:23:44 +0000 |
| commit | 6a7d263e8b86d13efa04a7fc64ec37103d03d73e (patch) | |
| tree | 33a6331b66d68d7d8497366893de2e548934765e | |
| parent | 9a4d525b7df6f5274f438bebf05414f93b619e78 (diff) | |
| download | llvm-6a7d263e8b86d13efa04a7fc64ec37103d03d73e.tar.gz llvm-6a7d263e8b86d13efa04a7fc64ec37103d03d73e.tar.bz2 llvm-6a7d263e8b86d13efa04a7fc64ec37103d03d73e.tar.xz | |
Fix vectorizer docs.
This example is not vectorized because LLVM does not prove no-wrapping of
"a[i*7] += ...".
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@203734 91177308-0d34-0410-b5e6-96231b3b80d8
| -rw-r--r-- | docs/Vectorizers.rst | 9 |
1 files changed, 6 insertions, 3 deletions
diff --git a/docs/Vectorizers.rst b/docs/Vectorizers.rst index 61ebca2bb5..823fd9e670 100644 --- a/docs/Vectorizers.rst +++ b/docs/Vectorizers.rst @@ -182,11 +182,14 @@ that scatter/gathers memory. .. code-block:: c++ - int foo(int *A, int *B, int n, int k) { - for (int i = 0; i < n; ++i) - A[i*7] += B[i*k]; + int foo(int * A, int * B, int n) { + for (intptr_t i = 0; i < n; ++i) + A[i] += B[i*4]; } +In many situations the cost model will inform LLVM that this is not beneficial +and LLVM will only vectorize such code if forced with "-mllvm -force-vector-width=#". + Vectorization of Mixed Types ^^^^^^^^^^^^^^^^^^^^^^^^^^^^ |