This reverts commit 9c319d5bb40785c969d2af76535ca62448dfafa7.
Some issues were discovered with the bootstrap builds, which
seem like they were caused by this commit. I'm reverting to investigate.
The lowering happens in post-legalizer lowering if any source registers
from G_BUILD_VECTOR are not constants.
Add pattern pragment setting `scalar_to_vector ($src)` asequivalent to
`vector_insert (undef), ($src), (i61 0)`
v8f16 is a legal type but promoting to v16f16 would result in an illegal
type.
Let's legalize these by a combination of splitting+promoting resulting
in a pair of v4f16.
Also, we were being overly cautious with different v4f16 nodes. Mark
more of them safe to promote to v4f32.
Similar to d39b4ce3ce8a3c256e01bdec2b140777a332a633
Using "eabi" or "gnueabi" for aarch64 targets is a common mistake and
warned by Clang Driver. We want to avoid them elsewhere as well. Just
use the common "aarch64" without other triple components.
PR #66334 tried to renumber slot indexes before register allocation, but
the numbering was still affected by list entries for instructions which
had been erased. Fix this to make the register allocator's live range
length heuristics even less dependent on the history of how instructions
have been added to and removed from SlotIndexes's maps.
RegAllocGreedy uses SlotIndexes::getApproxInstrDistance to approximate
the length of a live range for its heuristics. Renumbering all slot
indexes with the default instruction distance ensures that this estimate
will be as accurate as possible, and will not depend on the history of
how instructions have been added to and removed from SlotIndexes's maps.
This also means that enabling -early-live-intervals, which runs the
SlotIndexes analysis earlier, will not cause large amounts of churn due
to different register allocator decisions.
This adds some more extensive test coverage for fdiv through global isel,
switching the opcodes to use the more complete ActionDefinitions to handle more
cases and moving it into the position of the existing code which is no longer
needed.
