[PATCH] D126085: [RISCV] Add a subtarget feature to enable unaligned scalar loads and stores

[Alex Bradbury via Phabricator via llvm-commits]

asb added a comment.

I don't think it affects this patch (as splitting scalar vs vector features for alignment makes sense regardless of the frontend option), but I had a quick look at the frontend option for this. Looks like on the GCC side it's `-mno-strict-align`. On Arm/AArch64 it's spelled `-munaligned-access` and `__ARM_FEATURE_UNALIGNED` is set. Unless there's some target generic `#define` that's set that I'm missing, it feels like it would be useful to set a define for the RISC-V case as well (and agree this with the GNU folks).

One thing I noticed that does affect this patch (and sorry I didn't spot this earlier!), is we should be setting `Tag_RISCV_unaligned_access` when this feature is set (see here <https://github.com/riscv-non-isa/riscv-elf-psabi-doc/blob/master/riscv-elf.adoc#list-of-attributes>).


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