This enables subreg liveness in the arm backend when MVE is present,
which allows the register allocator to detect when subregister are
alive/dead, compared to only acting on full registers. This can helps
produce better code on MVE with the way MQPR registers are made up of
SPR registers, but is especially helpful for MQQPR and MQQQQPR
registers, where there are very few "registers" available and being able
to split them up into subregs can help produce much better code.
Differential Revision: https://reviews.llvm.org/D107642
Similar to D91921 (and D104515) this introduces two MVESEXT and MVEZEXT
nodes that larger-than-legal sext and zext are lowered to. These either
get optimized away or end up becoming a series of stack loads/store, in
order to perform the extending whilst keeping the order of the lanes
correct. They are generated from v8i16->v8i32, v16i8->v16i16 and
v16i8->v16i32 extends, potentially with a intermediate extend for the
larger v16i8->v16i32 extend. A number of combines have been added for
obvious cases that come up in tests, notably MVEEXT of shuffles. More
may be needed in the future, but this seems to cover most of the cases
that come up in the tests.
Differential Revision: https://reviews.llvm.org/D105090
This adds code to lower f16 to f32 fp_exts's using an MVE VCVT
instructions, similar to a recent similar patch for fp_trunc. Again it
goes through the lowering of a BUILD_VECTOR, but is slightly simpler
only having to deal with interleaved indices. It adds a VCVTL node to
lower to, similar to VCVTN.
Differential Revision: https://reviews.llvm.org/D81339
Summary:
These intrinsics take a vector of 2n elements, and return a vector of
n wider elements obtained by sign- or zero-extending every other
element of the input vector. They're represented in IR as a
shufflevector that extracts the odd or even elements of the input,
followed by a sext or zext.
Existing LLVM codegen already matches this pattern and generates the
VMOVLB instruction (which widens the even-index input lanes). But no
existing isel rule was generating VMOVLT, so I've added some. However,
the new rules currently only work in little-endian MVE, because the
pattern they expect from isel lowering includes a bitconvert which
doesn't have the right semantics in big-endian.
The output of one existing codegen test is improved by those new
rules.
This commit adds the unpredicated forms only.
Reviewers: dmgreen, miyuki, MarkMurrayARM, ostannard
Reviewed By: dmgreen
Subscribers: kristof.beyls, hiraditya, cfe-commits, llvm-commits
Tags: #clang, #llvm
Differential Revision: https://reviews.llvm.org/D74336
Identity shuffles, of the form (0, 1, 2, 3, ...) are perfectly OK under MVE
(they essentially just become bitcasts). We were not catching that in the
existing set of what we considered legal though. On NEON, they would be covered
by vext's, but that is not generally available in MVE.
This uses ShuffleVectorInst::isIdentityMask which is a little odd to use here
but does what we want and prevents us from just rewriting what is the same
function.
Differential Revision: https://reviews.llvm.org/D68241
llvm-svn: 373446
David Green