Lowering icmp was duplicated across callers that only cared about
flags, and callers that only cared about the bool result.
Merge both callers into `lower_icmp` which does the correct thing
depending on a new IcmpOutput parameter.
The previous address calculation code had a bug where we tried to
add offsets into a temporary register before defining it, causing
the regalloc to complain.
* Add support for processor features (including auto-detection).
* Move base architecture set requirement back to z14.
* Add z15 feature sets and re-enable z15-specific code generation
when required features are available.
This adds full back-end support for the Fence, AtomicLoad
and AtomicStore operations, and partial support for the
AtomicCas and AtomicRmw operations.
The missing pieces include sub-word operations, operations
on little-endian memory requiring byte-swapping, and some
of the subtypes of AtomicRmw -- everything that cannot be
implemented without a compare-and-swap loop. This will be
done in a follow-up patch.
This patch already suffices to make the test suite green
again after a recent change that now requires atomic
operations when accessing the heap.
We have 3 different aproaches depending on the type of comparision requested:
* For eq/ne we compare the high bits and low bits and check
if they are equal
* For overflow checks, we perform a i128 add and check the
resulting overflow flag
* For the remaining comparisions (gt/lt/sgt/etc...)
We compare both the low bits and high bits, and if the high bits are
equal we return the result of the unsigned comparision on the low bits
As with other i128 ops, we are still missing immlogic support.
Currently we just basically use a two instruction version of the same i64 ops.
IMMLogic doesn't really support multiple register inputs, so its left as a TODO for future optimizations.
* Add support for x64 packed promote low
* Add support for x64 packed floating point demote
* Update vector promote low and demote by adding constraints
Also does some renaming and minor refactoring
Previously, the multiple flags for certain AVX512 instructions were
checked using `OR`: e.g., if the CPU has AVX512VL `OR` AVX512DQ,
emit `VPMULLQ`. This is incorrect--the logic should be `AND`. The Intel
Software Developer Manual, vol. 1, sec. 15.4, has more information on
this (notable there is the suggestion to check with `XGETBV` that the OS
is allowing the use of the XMM registers--but that is a separate issue).
This change switches to `AND` logic in the new backend.
When shuffling values from two different registers, the x64 lowering for
`i8x16.shuffle` must first shuffle each register separately and then OR
the results with SSE instructions. With `VPERMI2B`, available in
AVX512VL + AVX512VBMI, this can be done in a single instruction after
the shuffle mask has been moved into the destination register. This
change uses `VPERMI2B` for that case when the CPU supports it.
The previous choice to use the WasmtimeSystemV calling convention for
apple-aarch64 devices was incorrect: padding of arguments was
incorrectly computed. So we have to use some flavor of the apple-aarch64
ABI there.
Since we want to support the wasmtime custom convention for multiple
returns on apple-aarch64 too, a new custom Wasmtime calling convention
was introduced to support this.
cranelift-codegen's build failed on s390x, with this error:
```
error[E0432]: unresolved import `crate::isa::unwind::systemv`
--> cranelift/codegen/src/isa/s390x/mod.rs:6:25
|
6 | use crate::isa::unwind::systemv::RegisterMappingError;
| ^^^^^^^ could not find `systemv` in `unwind`
```
This import should be used only with `unwind` feature enabled.
When AVX512VL or AVX512BITALG are available, Wasm SIMD's `popcnt`
instruction can be lowered to a single x64 instruction, `VPOPCNTB`,
instead of 8+ instructions.
This is sometimes useful when performing analyses on the generated
machine code: for example, some kinds of code verifiers will want to do
a control-flow analysis, and it is much easier to do this if one does
not have to recover the CFG from the machine code (doing so requires
heavyweight analysis when indirect branches are involved). If one trusts
the control-flow lowering and only needs to verify other properties of
the code, this can be very useful.
When AVX512VL and AVX512F are available, use a single instruction
(`VCVTUDQ2PS`) instead of a length 9-instruction sequence. This
optimization is a port from the legacy x86 backend.
Previously, the x64 backend's ABI code would generate a sign-extending
load when loading a less-than-64-bit integer from a spillslot. This is
incorrect: e.g., for i32s > 0x80000000, this would result in all high
bits set.
This interacts poorly with another optimization. Normally, the invariant
is that the high bits of a register holding a value of a certain type,
beyond that type's bits, are undefined. However, as an optimization, we
recognize and use the fact that on x86-64, 32-bit instructions zero the
upper 32 bits. This allows us to elide a 32-to-64-bit zero-extend op
(turning it into just a move, which can then sometimes disappear
entirely due to register coalescing).
If a spill and reload happen between the production of a 32-bit value
from an instruction known to zero the upper bits and its use, then we
will rely on zero upper bits that might actually be set by a
sign-extend. This will result in incorrect execution.
As a fix, we stick to a simple invariant: we always spill and reload a
full 64 bits when handling integer registers on x64. This ensures that
no bits are mangled.
This change implements `vselect` using SSE4.1's `BLENDVPS`, `BLENDVPD`,
and `PBLENDVB`. `vselect` is a lane-selecting instruction that is used
by
[simple_preopt.rs](fa1faf5d22/cranelift/codegen/src/simple_preopt.rs (L947-L999))
to lower `bitselect` to a single x86 instruction when the condition mask
is known to be boolean (all 1s or 0s, e.g., from a conversion). This is
better than `bitselect` in general, which lowers to 4-5 instructions.
The old backend had the `vselect` lowering; this simply introduces it to
the new backend.
Since `uadd_sat`, `sadd_sat`, `usub_sat`, and `ssub_sat` are now only
available to vector types, this removes the lowering code for the
scalar versions of these instructions in the arm32 and aarch64 backends.
This adds the machinery to encode the VPMULLQ instruction which is
available in AVX512VL and AVX512DQ. When these feature sets are
available, we use this instruction instead of a lengthy 12-instruction
sequence.
Since the lowering of `imul` complicated the other ALU operations it was
matched with and since future commits will alter the multiplication
lowering further, this change moves the `imul` lowering to its own match
block.
In order to benchmark the encoding code with criterion, the functions
and structures must be public. Moving this code to its own module
(instead of keeping as a submodule to `inst`), allows `inst` to remain
private. This avoids having to expose and document (or ignore
documenting) the numerous instruction variants in `inst` while allowing
access to the encoding code. This commit changes no functionality.
When dealing with params that need to be split, we follow the
arch64 ABI and split the value in two, and make sure that start that
argument in an even numbered xN register.
The apple ABI does not require this, so on those platforms, we start
params anywhere.
