• Implement canonicalisation for the fixed case.
• Move intrinsic into llvm.experimental namespace.
• Update documentation and tests accordingly.

@lebedev.ri, hi! We submitted an RFC for named shuffle intrinsics to the llvm-dev mailing list (here). Do you think this is sufficient? Note there are still a few changes left to do on this patch (mainly moving the intrinsics to the experimental namespace and adding canonicalisation to shufflevector for the fixed case). 😄

Move and re-flow comment lines.

Planning to add canonicalization to shufflevector for fixed-width vectors.

Thank you @fhahn, that comment was super helpful. I've opted to create a new test here because I didn't want to change the relationship between the IR and the C++ at the top of memcheck-off-by-on-error.ll. If you think this is the wrong thing to do, just let me know. 😄

Add test to defend against accidentally using alloc size instead of store size.

Fix failing tests (forgot to write stderr to %t).

Auto-generate tests.

Address @paulwalker-arm's comments.

@fhahn Hi! Do you have any objections to landing this as-is without the additional test? Alternatively, any recommendations on how to test this? 😄

Avoid doing FirstType->getAs<BuiltinType>().

Address @c-rhodes's comments regarding lax conversion when __ARM_FEATURE_SVE_BITS != N for GNU vectors.

Remove redundant tests from clang/test/Sema/attr-arm-sve-vector-bits.c.

Address @c-rhodes's comment regarding comment change.

Address @c-rhodes's and @peterwaller-arm's comments.

• Address @peterwaller-arm's comments.
• Fix off-by-one error in Intrinsics.td.

Remove failing test; it was checking that a conversion _failed_, although the conversion should now _pass_ given the changes in this patch.

Address @sdesmalen and @paulwalker-arm review comments.

Thanks for the patch @fpetrogalli! One small comment from me, but not a blocker for me, so approved.

• Support C lax vector conversions.
• Test C lax vector conversions.

Address @c-rhodes's comments.

Address @fpetrogalli's comments.

Add tests for C-style casts to/from scalable/fixed float vector types.

Address @fpetrogalli's comments.

@fpetrogalli sure!

Address @peterwaller-arm's comment regarding unused types.

Get rid of -mtriple and -mattr flags, since these are also superfluous.

Address @fhahn's comments.

Address @fhahn's suggestions.

LGTM. Also see @arm-chrjan01's old patch here: https://reviews.llvm.org/D44822

Address sdesmalen's review comments.

Oops -- be sure to use getFixedSize.

Use pointer element type to check if this is a scalar GEP.

Move scalable vector check to the top of the function as-per sdesmalen's suggestion.

Use isa<...> instead of dyn_cast<...>.

Address fpetrogalli's suggestion.

Bail out early if we have scalable vectors.

Accidentally changed int64_t to uint64_t in the last diff. Reverted this.

Revert to single-line if statement, add description to the test, and add an
additional check line.

Address peterwaller-arm's comments regarding control flow readability