[LLVMdev] Does loop vectorizer inquire about target's SIMD capabilities?

Renato Golin renato.golin at linaro.org
Thu Jan 3 15:04:48 PST 2013

On 3 January 2013 22:09, Nadav Rotem <nrotem at apple.com> wrote:

> The loop vectorizer is now enabled by default.

I thought that was just a temporary arrangement to get the feel for it, not
to actually have it on all the time (next release). Is it just for -O3 or
lower too?

This can cause problems, for instance on ARMv7, the default is that NEON is
present, but Tegra2 doesn't have NEON, only VFP. It means an optimizing
compilation that used to work on it will fail, unless you specify no NEON
or no vectorization explicitly, no?

I'd prefer if -vectorization had to be passed explicitly to get it done on
production releases of LLVM or something else (-O4 or -OV, for example).

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