T0b1/wasmtime
1
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity

x64: Enable load-coalescing for SSE/AVX instructions (#5841)

Browse Source 
* x64: Enable load-coalescing for SSE/AVX instructions

This commit unlocks the ability to fold loads into operands of SSE and
AVX instructions. This is beneficial for both function size when it
happens in addition to being able to reduce register pressure.
Previously this was not done because most SSE instructions require
memory to be aligned. AVX instructions, however, do not have alignment
requirements.

The solution implemented here is one recommended by Chris which is to
add a new `XmmMemAligned` newtype wrapper around `XmmMem`. All SSE
instructions are now annotated as requiring an `XmmMemAligned` operand
except for a new new instruction styles used specifically for
instructions that don't require alignment (e.g.  `movdqu`, `*sd`, and
`*ss` instructions). All existing instruction helpers continue to take
`XmmMem`, however. This way if an AVX lowering is chosen it can be used
as-is. If an SSE lowering is chosen, however, then an automatic
conversion from `XmmMem` to `XmmMemAligned` kicks in. This automatic
conversion only fails for unaligned addresses in which case a load
instruction is emitted and the operand becomes a temporary register
instead. A number of prior `Xmm` arguments have now been converted to
`XmmMem` as well.

One change from this commit is that loading an unaligned operand for an
SSE instruction previously would use the "correct type" of load, e.g.
`movups` for f32x4 or `movup` for f64x2, but now the loading happens in
a context without type information so the `movdqu` instruction is
generated. According to [this stack overflow question][question] it
looks like modern processors won't penalize this "wrong" choice of type
when the operand is then used for f32 or f64 oriented instructions.

Finally this commit improves some reuse of logic in the `put_in_*_mem*`
helper to share code with `sinkable_load` and avoid duplication. With
this in place some various ISLE rules have been updated as well.

In the tests it can be seen that AVX-instructions are now automatically
load-coalesced and use memory operands in a few cases.

[question]: https://stackoverflow.com/questions/40854819/is-there-any-situation-where-using-movdqu-and-movupd-is-better-than-movups

* Fix tests

* Fix move-and-extend to be unaligned

These don't have alignment requirements like other xmm instructions as
well. Additionally add some ISA tests to ensure that their output is
tested.

* Review comments
This commit is contained in:
Alex Crichton
2023-02-21 13:10:19 -06:00
committed by GitHub
parent c65de1f1b1
commit d82ebcc102
11 changed files with 644 additions and 323 deletions
Download Patch File Download Diff File Expand all files Collapse all files

225
cranelift/codegen/src/isa/x64/inst/args.rs
View File

@@ -31,8 +31,8 @@ macro_rules! newtype_of_reg {
$newtype_reg:ident,
$newtype_writable_reg:ident,
$newtype_option_writable_reg:ident,
$newtype_reg_mem:ident,
$newtype_reg_mem_imm:ident,
reg_mem: ($($newtype_reg_mem:ident $(aligned:$aligned:ident)?),*),
reg_mem_imm: ($($newtype_reg_mem_imm:ident $(aligned:$aligned_imm:ident)?),*),
$newtype_imm8_reg:ident,
|$check_reg:ident| $check:expr
) => {
@@ -102,108 +102,130 @@ macro_rules! newtype_of_reg {
}
}
/// A newtype wrapper around `RegMem` for general-purpose registers.
#[derive(Clone, Debug)]
pub struct $newtype_reg_mem(RegMem);
$(
/// A newtype wrapper around `RegMem` for general-purpose registers.
#[derive(Clone, Debug)]
pub struct $newtype_reg_mem(RegMem);
impl From<$newtype_reg_mem> for RegMem {
fn from(rm: $newtype_reg_mem) -> Self {
rm.0
}
}
impl From<$newtype_reg> for $newtype_reg_mem {
fn from(r: $newtype_reg) -> Self {
$newtype_reg_mem(RegMem::reg(r.into()))
}
}
impl $newtype_reg_mem {
/// Construct a `RegMem` newtype from the given `RegMem`, or return
/// `None` if the `RegMem` is not a valid instance of this `RegMem`
/// newtype.
pub fn new(rm: RegMem) -> Option<Self> {
match rm {
RegMem::Mem { addr: _ } => Some(Self(rm)),
RegMem::Reg { reg: $check_reg } if $check => Some(Self(rm)),
RegMem::Reg { reg: _ } => None,
impl From<$newtype_reg_mem> for RegMem {
fn from(rm: $newtype_reg_mem) -> Self {
rm.0
}
}
/// Convert this newtype into its underlying `RegMem`.
pub fn to_reg_mem(self) -> RegMem {
self.0
}
#[allow(dead_code)] // Used by some newtypes and not others.
pub(crate) fn get_operands<F: Fn(VReg) -> VReg>(
&self,
collector: &mut OperandCollector<'_, F>,
) {
self.0.get_operands(collector);
}
}
impl PrettyPrint for $newtype_reg_mem {
fn pretty_print(&self, size: u8, allocs: &mut AllocationConsumer<'_>) -> String {
self.0.pretty_print(size, allocs)
}
}
/// A newtype wrapper around `RegMemImm`.
#[derive(Clone, Debug)]
pub struct $newtype_reg_mem_imm(RegMemImm);
impl From<$newtype_reg_mem_imm> for RegMemImm {
fn from(rmi: $newtype_reg_mem_imm) -> RegMemImm {
rmi.0
}
}
impl From<$newtype_reg> for $newtype_reg_mem_imm {
fn from(r: $newtype_reg) -> Self {
$newtype_reg_mem_imm(RegMemImm::reg(r.into()))
}
}
impl From<$newtype_reg_mem> for $newtype_reg_mem_imm {
fn from(r: $newtype_reg_mem) -> Self {
$newtype_reg_mem_imm(r.0.into())
}
}
impl $newtype_reg_mem_imm {
/// Construct this newtype from the given `RegMemImm`, or return
/// `None` if the `RegMemImm` is not a valid instance of this
/// newtype.
pub fn new(rmi: RegMemImm) -> Option<Self> {
match rmi {
RegMemImm::Imm { .. } => Some(Self(rmi)),
RegMemImm::Mem { addr: _ } => Some(Self(rmi)),
RegMemImm::Reg { reg: $check_reg } if $check => Some(Self(rmi)),
RegMemImm::Reg { reg: _ } => None,
impl From<$newtype_reg> for $newtype_reg_mem {
fn from(r: $newtype_reg) -> Self {
$newtype_reg_mem(RegMem::reg(r.into()))
}
}
/// Convert this newtype into its underlying `RegMemImm`.
#[allow(dead_code)] // Used by some newtypes and not others.
pub fn to_reg_mem_imm(self) -> RegMemImm {
self.0
impl $newtype_reg_mem {
/// Construct a `RegMem` newtype from the given `RegMem`, or return
/// `None` if the `RegMem` is not a valid instance of this `RegMem`
/// newtype.
pub fn new(rm: RegMem) -> Option<Self> {
match rm {
RegMem::Mem { addr } => {
let mut _allow = true;
$(
if $aligned {
_allow = addr.aligned();
}
)?
if _allow {
Some(Self(RegMem::Mem { addr }))
} else {
None
}
}
RegMem::Reg { reg: $check_reg } if $check => Some(Self(rm)),
RegMem::Reg { reg: _ } => None,
}
}
/// Convert this newtype into its underlying `RegMem`.
pub fn to_reg_mem(self) -> RegMem {
self.0
}
#[allow(dead_code)] // Used by some newtypes and not others.
pub(crate) fn get_operands<F: Fn(VReg) -> VReg>(
&self,
collector: &mut OperandCollector<'_, F>,
) {
self.0.get_operands(collector);
}
}
impl PrettyPrint for $newtype_reg_mem {
fn pretty_print(&self, size: u8, allocs: &mut AllocationConsumer<'_>) -> String {
self.0.pretty_print(size, allocs)
}
}
)*
$(
/// A newtype wrapper around `RegMemImm`.
#[derive(Clone, Debug)]
pub struct $newtype_reg_mem_imm(RegMemImm);
impl From<$newtype_reg_mem_imm> for RegMemImm {
fn from(rmi: $newtype_reg_mem_imm) -> RegMemImm {
rmi.0
}
}
#[allow(dead_code)] // Used by some newtypes and not others.
pub(crate) fn get_operands<F: Fn(VReg) -> VReg>(
&self,
collector: &mut OperandCollector<'_, F>,
) {
self.0.get_operands(collector);
impl From<$newtype_reg> for $newtype_reg_mem_imm {
fn from(r: $newtype_reg) -> Self {
$newtype_reg_mem_imm(RegMemImm::reg(r.into()))
}
}
}
impl PrettyPrint for $newtype_reg_mem_imm {
fn pretty_print(&self, size: u8, allocs: &mut AllocationConsumer<'_>) -> String {
self.0.pretty_print(size, allocs)
impl $newtype_reg_mem_imm {
/// Construct this newtype from the given `RegMemImm`, or return
/// `None` if the `RegMemImm` is not a valid instance of this
/// newtype.
pub fn new(rmi: RegMemImm) -> Option<Self> {
match rmi {
RegMemImm::Imm { .. } => Some(Self(rmi)),
RegMemImm::Mem { addr } => {
let mut _allow = true;
$(
if $aligned_imm {
_allow = addr.aligned();
}
)?
if _allow {
Some(Self(RegMemImm::Mem { addr }))
} else {
None
}
}
RegMemImm::Reg { reg: $check_reg } if $check => Some(Self(rmi)),
RegMemImm::Reg { reg: _ } => None,
}
}
/// Convert this newtype into its underlying `RegMemImm`.
#[allow(dead_code)] // Used by some newtypes and not others.
pub fn to_reg_mem_imm(self) -> RegMemImm {
self.0
}
#[allow(dead_code)] // Used by some newtypes and not others.
pub(crate) fn get_operands<F: Fn(VReg) -> VReg>(
&self,
collector: &mut OperandCollector<'_, F>,
) {
self.0.get_operands(collector);
}
}
}
impl PrettyPrint for $newtype_reg_mem_imm {
fn pretty_print(&self, size: u8, allocs: &mut AllocationConsumer<'_>) -> String {
self.0.pretty_print(size, allocs)
}
}
)*
/// A newtype wrapper around `Imm8Reg`.
#[derive(Clone, Debug)]
@@ -242,8 +264,8 @@ newtype_of_reg!(
Gpr,
WritableGpr,
OptionWritableGpr,
GprMem,
GprMemImm,
reg_mem: (GprMem),
reg_mem_imm: (GprMemImm),
Imm8Gpr,
|reg| reg.class() == RegClass::Int
);
@@ -253,8 +275,8 @@ newtype_of_reg!(
Xmm,
WritableXmm,
OptionWritableXmm,
XmmMem,
XmmMemImm,
reg_mem: (XmmMem, XmmMemAligned aligned:true),
reg_mem_imm: (XmmMemImm, XmmMemAlignedImm aligned:true),
Imm8Xmm,
|reg| reg.class() == RegClass::Float
);
@@ -420,6 +442,10 @@ impl Amode {
}
ret
}
pub(crate) fn aligned(&self) -> bool {
self.get_flags().aligned()
}
}
impl PrettyPrint for Amode {
@@ -531,6 +557,13 @@ impl SyntheticAmode {
}
}
}
pub(crate) fn aligned(&self) -> bool {
match self {
SyntheticAmode::Real(addr) => addr.aligned(),
SyntheticAmode::NominalSPOffset { .. } | SyntheticAmode::ConstantOffset { .. } => true,
}
}
}
impl Into<SyntheticAmode> for Amode {