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Keep results in xmm register if it is used in next instruction
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@benruijl
benruijl committed Aug 12, 2024
1 parent a8c7316 commit 2858d0b
Showing 1 changed file with 153 additions and 25 deletions.
178 changes: 153 additions & 25 deletions src/evaluate.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -1269,34 +1269,146 @@ impl<T: std::fmt::Display> ExpressionEvaluator<T> {
}

let mut in_asm_block = false;
for ins in instr {
match ins {
Instr::Add(o, a) => {
if !in_asm_block {
*out += "\t__asm__(\n";
in_asm_block = true;
}
let mut regcount = 0;

*out += &format!("\t\t\"movsd xmm0, QWORD {}\\n\\t\"\n", format_addr!(a[0]));
fn reg_unused(reg: usize, instr: &[Instr], out: &[usize]) -> bool {
if out.contains(&reg) {
return false;
}

// TODO: try loading in multiple registers for better instruction-level parallelism?
for i in &a[1..] {
*out += &format!("\t\t\"addsd xmm0, QWORD {}\\n\\t\"\n", format_addr!(*i));
for ins in instr {
match ins {
Instr::Add(r, a) | Instr::Mul(r, a) => {
if a.iter().any(|x| *x == reg) {
return false;
}

if r == &reg {
return true;
}
}
Instr::Pow(r, b, _) => {
if *b == reg {
return false;
}
if r == &reg {
return true;
}
}
Instr::Powf(r, b, e) => {
if *b == reg || *e == reg {
return false;
}
if r == &reg {
return true;
}
}
Instr::BuiltinFun(r, _, b) => {
if *b == reg {
return false;
}
if r == &reg {
return true;
}
}
*out += &format!("\t\t\"movsd QWORD {}, xmm0\\n\\t\"\n", format_addr!(*o));
}
Instr::Mul(o, a) => {
}

true
}

let mut recycle_register: (Option<(usize, u32)>, Option<(usize, u32)>) = (None, None); // old and current register
for (i, ins) in instr.iter().enumerate() {
// keep results in xmm registers if the last use is in the next instruction
if let Some(ii) = instr.get(i + 1) {
match ins {
Instr::Add(r, _) | Instr::Mul(r, _) => match ii {
Instr::Add(j, _) | Instr::Mul(j, _) => {
if r == j || reg_unused(*r, &instr[i + 2..], &self.result_indices) {
if let Some(old) = recycle_register.0 {
recycle_register.1 = Some((*r, old.1));
} else {
recycle_register.1 = Some((*r, regcount));
}
}
}
_ => {}
},
_ => {}
}
}

match ins {
Instr::Add(o, a) | Instr::Mul(o, a) => {
if !in_asm_block {
*out += "\t__asm__(\n";
in_asm_block = true;
}

*out += &format!("\t\t\"movsd xmm0, QWORD {}\\n\\t\"\n", format_addr!(a[0]));
let oper = if matches!(ins, Instr::Add(_, _)) {
"add"
} else {
"mul"
};

if let Some(old) = recycle_register.0 {
assert!(a.iter().any(|rr| *rr == old.0)); // the last value must be used

for i in &a[1..] {
*out += &format!("\t\t\"mulsd xmm0, QWORD {}\\n\\t\"\n", format_addr!(*i));
for i in a {
if *i != old.0 {
*out += &format!(
"\t\t\"{}sd xmm{}, QWORD {}\\n\\t\"\n",
oper,
old.1,
format_addr!(*i)
);
}
}

if recycle_register.1.is_none() {
*out += &format!(
"\t\t\"movsd QWORD {}, xmm{}\\n\\t\"\n",
format_addr!(*o),
old.1,
);
}
} else if let Some(new) = recycle_register.1 {
*out += &format!(
"\t\t\"movsd xmm{}, QWORD {}\\n\\t\"\n",
new.1,
format_addr!(a[0])
);

for i in &a[1..] {
*out += &format!(
"\t\t\"{}sd xmm{}, QWORD {}\\n\\t\"\n",
oper,
new.1,
format_addr!(*i)
);
}
} else {
*out += &format!(
"\t\t\"movsd xmm{}, QWORD {}\\n\\t\"\n",
regcount,
format_addr!(a[0])
);

for i in &a[1..] {
*out += &format!(
"\t\t\"{}sd xmm{}, QWORD {}\\n\\t\"\n",
oper,
regcount,
format_addr!(*i)
);
}

*out += &format!(
"\t\t\"movsd QWORD {}, xmm{}\\n\\t\"\n",
format_addr!(*o),
regcount,
);
}
*out += &format!("\t\t\"movsd QWORD {}, xmm0\\n\\t\"\n", format_addr!(*o));
}
Instr::Pow(o, b, e) => {
if *e == -1 {
Expand All @@ -1306,10 +1418,10 @@ impl<T: std::fmt::Display> ExpressionEvaluator<T> {
}

*out += &format!(
"\t\t\"movsd xmm0, QWORD PTR [%1+{}]\\n\\t\"
\t\t\"divsd xmm0, QWORD {}\\n\\t\"
\t\t\"movapd xmm2, xmm0\\n\\t\"
\t\t\"movsd QWORD {}, xmm0\\n\\t\"\n",
"\t\t\"movsd xmm{0}, QWORD PTR [%1+{1}]\\n\\t\"
\t\t\"divsd xmm{0}, QWORD {2}\\n\\t\"
\t\t\"movsd QWORD {3}, xmm{0}\\n\\t\"\n",
regcount,
(self.reserved_indices - self.param_count) * 8,
format_addr!(*b),
format_addr!(*o)
Expand Down Expand Up @@ -1353,24 +1465,40 @@ impl<T: std::fmt::Display> ExpressionEvaluator<T> {
}
}
}

recycle_register.0 = recycle_register.1.take();
}

end_asm_block!(in_asm_block);

*out += "\t__asm__(\n";
for (i, r) in &mut self.result_indices.iter().enumerate() {
if *r < self.param_count {
*out += &format!("\t\t\"movsd xmm0, QWORD PTR[%3+{}]\\n\\t\"\n", r * 8);
*out += &format!(
"\t\t\"movsd xmm{}, QWORD PTR[%3+{}]\\n\\t\"\n",
regcount,
r * 8
);
} else if *r < self.reserved_indices {
*out += &format!(
"\t\t\"movsd xmm0, QWORD PTR[%2+{}]\\n\\t\"\n",
"\t\t\"movsd xmm{}, QWORD PTR[%2+{}]\\n\\t\"\n",
regcount,
(r - self.param_count) * 8
);
} else {
*out += &format!("\t\t\"movsd xmm0, QWORD PTR[%1+{}]\\n\\t\"\n", r * 8);
*out += &format!(
"\t\t\"movsd xmm{}, QWORD PTR[%1+{}]\\n\\t\"\n",
regcount,
r * 8
);
}

*out += &format!("\t\t\"movsd QWORD PTR[%0+{}], xmm0\\n\\t\"\n", i * 8);
*out += &format!(
"\t\t\"movsd QWORD PTR[%0+{}], xmm{}\\n\\t\"\n",
i * 8,
regcount
);
regcount = (regcount + 1) % 16;
}

*out += "\t\t:\n\t\t: \"r\"(out), \"r\"(Z), \"r\"(CONSTANTS_double), \"r\"(params)\n\t\t: \"memory\", \"xmm0\");\n";
Expand Down

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