The MVE_VLDRWU32_qi_pre gather loads, like the other _pre/_post mve
loads returns the writeback as result 0, the value as result 1. The llvm
ir intrinsic seems to have this the other way around though, and so when
lowering from one to the other we need to switch the first two outputs.
I've also fixed up the types of _pre/_post on normal MVE loads. There we
were already getting the values the right way around, just not for the
types. I don't believe this was causing anything to go wrong, but it was
very confusing to read in the debug output.
Differential Revision: https://reviews.llvm.org/D73370
This adds some initial example IR intrinsics for MVE instructions that
deliver multiple output values, and hence, have to be instruction-
selected by custom C++ code instead of Tablegen patterns.
I've added the writeback gather load instructions (taking a vector of
base addresses and a single common offset, returning a vector of
loaded values and an updated vector of base addresses); one example
from the long shift family (taking and returning a 64-bit value in two
GPRs); and the VADC instruction (which propagates a carry bit from
each vector-lane addition to the next, taking an input carry flag in
FPSCR and outputting the final one in FPSCR as well).
To support the VPT-predicated forms of these instructions, I've
written some helper functions to add the cluster of MVE predicate
operands to the end of a MachineInstr. `AddMVEPredicateToOps` is used
when the instruction actually is predicated (so it takes a predicate
mask argument), and `AddEmptyMVEPredicateToOps` is for when the
instruction is unpredicated (so it fills in $noreg for the mask). Each
one comes in a form suitable for `vpred_n`, and one for `vpred_r`
which takes the extra 'inactive' parameter.
For VADC, the representation of the carry flag in the IR intrinsic is
a word intended to be moved directly to and from `FPSCR_nzcvqc`, i.e.
with the carry flag in bit 29 of the word. (The user-facing ACLE
intrinsic will want it to be in bit 0, but I'll do that on the clang
side.)
Reviewers: dmgreen, miyuki, ostannard
Subscribers: kristof.beyls, hiraditya, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D68699
David Green