The canonical way to generate a zero register vector in x86 is to xor
itself. Capture this can convert it to canonical zero register instead.
Can get zero-cycle renamed on latest CPUs.
We can support a few combinations of guest and host vector sizes
Host: 128-bit or 256-bit
Guest: 128-bit or 256-bit
The typical case is Host = 128-bit and Guest = 256-bit now that AVX is
implemented.
On 32-bit this changes to Host=128-bit and Guest=128-bit because we
disable AVX.
In the vixl simulator 32-bit turns in to Host=256-bit and Guest=128-bit.
And then in the vixl sim 64-bit turns in to Host=256-bit and
Guest=256-bit.
We cover all four combinations of guest and host vector register sizes!
Fixes a few assumptions that SVE256 = AVX256 basically.
When the source or destination is a register, the address size override
doesn't apply. We were accidentally applying it on all sources
regardless of type which was causing us to zero extend on operations
that aren't affected by address size override.
This fixes the OpenSSL cert error in every application, but most
importantly Steam.
Only installs the tables if SVE256 isn't supported yet AVX is explicitly
enabled with HostFeatures, to protect accidental enablement early.
- Only implements 85 instructions starting out
- Basic vector moves
- Basic vector unary operations
- Basic vector binary operations
- VZeroUpper/VZeroAll
The bulk of the implementation is currently the handling for loading and
storing the halves of the registers from the context or from memory.
This means the load/store helpers must always return a pair unless only
requesting the bottom half of the register, which occurs with 128-bit
AVX operations. The store side then needing to consume the named zero
register if it occurs since those cases will zero the upper bits.
This implementation approach has a few benefits.
- I can pound this out extremely quickly
- SSE implementations are unaffected and don't need to deal with the
insert behaviour of SVE256.
- We still keep the SVE256 implementation for the inevitable future when
hardware vendors actually do implement it (Give it 8 years or
something).
- We can actually unit test this path in CI once it is complete.
- We can partially optimize some paths with SVE128 (Gathers) and support
a full ASIMD path if necessary.
One downside is that I can't enable this in CI yet because it can't pass
all unittests. but that's a non-issue since it is going to be in heavy
flux as I'm hammering out the implementation. It'll get switched on at
the end when it's passing all 1265 AVX unittests. Currently at 1001 on
this.
to be consistent with the scalar _Andn opcode, which is specifically named _Andn
and not _Bic.
noticed while reviewing AVX patches
Signed-off-by: Alyssa Rosenzweig <alyssa@rosenzweig.io>
In quite a few locations we are mixing the case that SVE256 == AVX or
that AVX means the guest register size is 256-bit.
While this is true today, this is entanglement is going to change very
quickly and cause confusion in follow-up PRs.
Now we have SVE128, SVE256, and SVE2 HostFeatures to disambiguate the
different features which mean different things.
This PR keeps the alias that `SupportsAVX` = `SupportsSVE256 && SupportsSVE2`
but that alias is going to very quickly change its definition.
FEX had a bug with this instruction where it was incorrectly using both
the address size override and operand size override to truncate the
immediate offset. This isn't how the instruction should behave as it
should actually ignore the address size override.
This now puts it correctly inline with how the jump instruction works
and adds a unit test to ensure it doesn't break again.
This fixes a crash from the Arch rootfs from the glibc dynamic linker
being compiling in a way where a call instruction was getting aligned
using this prefix (Since the compiler knew it does nothing).
find-and-replace across the tree, excluding IR.h itself.
also excluded IRValidation because its treatment of blocks blows up and will be
reformed in the new IR anyway.
Signed-off-by: Alyssa Rosenzweig <alyssa@rosenzweig.io>
New RA does not need it for correctness, and the slight slow down to new RA from
not compacting first is much smaller than the cost of compaction. Overall speeds
up node.js start time by ~6% on top of new RA.
Signed-off-by: Alyssa Rosenzweig <alyssa@rosenzweig.io>
This avoids a bunch of sharp edges for RA at a small cost when obscure
segment registers are used.
Signed-off-by: Alyssa Rosenzweig <alyssa@rosenzweig.io>
Ryan Houdek