The range check and clamping is necessary in the cases of passing x86
shift amounts directly through VUSHL/VSSHR.
Some AVX operations are still using these with range clamping. A future
investigation task should be the check if they can be switched over to
the wide variants that we implemented for the SSE instructions.
When consuming our own controlled data, we don't want the range clamping
to be enabled.
The number of times the implicit size calculation in GPR operations has
bit us is immeasurable and was a mistake from the start of the project.
The vector based operations never had this problem since they were
explicitly sized for a long time now.
This converts the base IR operations to be explicitly sized, but adds
implicit sized helpers for the moment while we work on removing implicit
usage from the OpcodeDispatcher.
Should be NFC at this moment but it is a big enough change that I want
it in before the "real" work starts.
Noticed that we hadn't ever enabled this, which was a concern when our
GPR operations weren't as strict about leaving garbage in the upper bits
when operating as a 32-bit operation.
Now that our ALU operations are more strict about enforcing upper bit
zeroing we can enable this.
This causes Half-Life: Source FPS to get to > 200FPS finally. Causes
significant performance improvements for 32-bit games because we're no
longer redundantly moving registers before and after every operation.
Causing a bunch of 3-4 instruction sequences to convert to 1.
RAValidation was making an assumption that GPR register class would only
have up to 16 registers for either SRA or dynamic registers.
When running a 32-bit application we allow 17 GPRs to be dynamically
allocated, since we can take 8 back from SRA in that case.
Just split the two classes in the RAValidation pass since they will
never overlap their allocation.
Fixes validation in `32Bit_Secondary/15_XX_0.asm` locally that changed
behaviour due to tinkering.
Use a named constant for loading the sign inversion, then EOR the second
source and just FAdd it all.
In a vacuum it isn't a significant improvement, but as soon as more than
one instruction is in a block it will eventually get optimized with
named constant caching and be a significant win.
Thanks to @rygorous for the idea!
This takes the two independent VSXT{U}N{2,} operations and merges them
in to a single IR operations.
In some cases this can result in a more optimal implementation since
there is no need for moves inbetween.
VRev32 matches Arm64 semantics directly.
LoadNamedVectorConstant allows FEX to quickly load "named constants".
This will allow us to have specific hardcoded vector constant values
that we can load with a ldr(State)+ldr(Value) and will be more abused in
the future.
This also allows us to do a very simple optimization in the future where
we can optimize away redundant loads of these loads if they are used
multiple times in the same block. (Not implemented here).
This matches x86 vector shift behaviour closely for ps{rl,ra,ll}{w,d,q}
where the vector is shifted by a scalar value that is 64-bits wide.
Anything larger than the element size will set that element to zero.
With SVE we have some new wide element shifts that match this behaviour
exactly (except supports wide shift sources rather than scalar).
This is a significant improvement even on platforms that only support
128-bit SVE.
This is a bit of tricky operation where due to our our usage of SSA, the
incoming source isn't guaranteed to end its live-range at this
instruction.
This gives us a behaviour where to be optimal we need to take different
paths depending on if the incoming address register is the same as the
destination node.
Once we have form of RA constraints or non-SSA IR form that can
guarantee this restriction then this will go away.
Changes the idiom used for constant mask generation to a ternary.
This pattern is definitely used elsewhere in code but we can get rid of
all instances here.
Due to Intel dropping support for legacy segment registers[1] there is a
concern that this will break legacy 32-bit software that is doing some
magic segment register handling.
Adds some simple telemetry for 32-bit applications that when they
encounter an instruction that sets the segment register or uses a
segment register that the JIT will do a /relatively/ quick four
instruction check to see if it is not a null segment.
It's not enough to just check if the segment index is 0 or not, 32-bit
Linux software starts with non-zero segment register indexes but the LDT
for each segment index is a null-descriptor.
Once the segment address is loaded, the IR operation will do a quick
check against zero and if it /isn't/ zero then set the telemetry value.
A very minor optimization that segment registers only get checked once
per block to ensure overhead stays low.
[1] https://www.intel.com/content/www/us/en/developer/articles/technical/envisioning-future-simplified-architecture.html
- 3.6 - Restricted Subset of Segmentation
- `Bases are supported for FS, GS, GDT, IDT, LDT, and TSS
registers; the base for CS, DS, ES, and SS is ignored for 32-bit
mode, same as 64-bit mode (treated as zero).`
- 4.2.17 - MOV to Segment Register
- Will fault if SS is written (Breaking anything that writes to
SS).
- Will not fault if CS, DS, ES are written (Thus it sets the
segment but gets ignored due to 3.6).
It is not an external component, and it makes paths needlessly long.
Ryan seemed amenable to this when we discussed on IRC earlier.
Signed-off-by: Alyssa Rosenzweig <alyssa@rosenzweig.io>
Ryan Houdek