Found using https://github.com/codespell-project/codespell
```
codespell RISCV --write-changes \
--ignore-words-list=FPR,fpr,VAs,ORE,WorstCase,hart,sie,MIs,FLE,fle,CarryIn,vor,OLT,VILL,vill,bu,pass-thru
```
This patches adds a 32 bit register class for use with Zfinx instructions. This makes them more similar to F instructions and allows us to only spill 32 bits.
I've added CodeGenOnly instructions for load/store using GPRF32 as that gave better results than insert_subreg/extract_subreg.
Function arguments use this new GPRF32 register class for f32 arguments with Zfinx. Eliminating the need to use RISCVISD::FMV* nodes.
This is similar to #107446 which adds a 16 bit register class.
This patches adds a 16 bit register class for use with Zhinx
instructions. This makes them more similar to Zfh instructions and
allows us to only spill 16 bits.
I've added CodeGenOnly instructions for load/store using GPRF16 as that
gave better results than insert_subreg/extract_subreg. I'm using FSGNJ
for GPRF16 copy with Zhinx as that gave better results. Zhinxmin will
use ADDI+subreg operations.
Function arguments use this new GPRF16 register class for f16 arguments
with Zhinxmin. Eliminating the need to use RISCVISD::FMV* nodes.
I plan to extend this idea to Zfinx next.
Track the live register state immediately before, instead of after,
MBBI. This makes it simple to track the state at the start or end of a
basic block without a separate (and poorly named) Tracking flag.
This changes the API of the backward(MachineBasicBlock::iterator I)
method, which now recedes to the state just before, instead of just
after, *I. Some clients are simplified by this change.
There is one small functional change shown in the lit tests where
multiple spilled registers all need to be reloaded before the same
instruction. The reloads will now be inserted in the opposite order.
This should not affect correctness.
Current implementation will rename both register in store instructions if
we store base address into memory with same base register, it's OK if
the offset is 0, however that is wrong transform if offset isn't 0, give
a smalle example here:
sd a0, 808(a0)
We should not transform into:
addi a2, a0, 768
sd a2, 40(a2)
That should just rename base address like this:
addi a2, a0, 768
sd a0, 40(a2)
Reviewed By: asb
Differential Revision: https://reviews.llvm.org/D128876
When optimizing for size, this pass searches for instructions that are
prevented from being compressed by one of the following:
1. The use of a single uncompressed register.
2. A base register + offset where the offset is too large to be
compressed and the base register may or may not already be compressed.
In the first case, if there is a compressed register available, then the
uncompressed register is copied to the compressed register and its uses
replaced. This is only done if there are enough uses that code size
would be improved.
In the second case, if a compressed register is available, then the
original base register is copied and adjusted such that:
new_base_register = base_register + adjustment
base_register + large_offset = new_base_register + small_offset
and the uses of the base register are replaced with the new base
register. Again this is only done if there are enough uses for code size
to be improved.
This pass was authored by Lewis Revill, with large offset optimization
added by Craig Blackmore.
Differential Revision: https://reviews.llvm.org/D92105
