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[maglev][arm64] Use one less scratch register in PushAllHelper

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Instead of pushing 2 arguments at the same time, we push 1 argument
together with padreg (to ensure alignment) and overwrite padreg
afterwards.
That way we can re-use scratch registers used for the first argument
to materialise the second one.

Bug: v8:7700
Change-Id: I6d32b61f6e75ec488b4cf4128ced966bcf0ed1bd
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/4161758
Commit-Queue: Patrick Thier <pthier@chromium.org>
Reviewed-by: Victor Gomes <victorgomes@chromium.org>
Auto-Submit: Patrick Thier <pthier@chromium.org>
Cr-Commit-Position: refs/heads/main@{#85251}
This commit is contained in:
pthier 2023-01-12 12:53:14 +01:00 committed by V8 LUCI CQ
parent 177eb46e5f
commit 2501a75575
1 changed files with 20 additions and 20 deletions
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40
src/maglev/arm64/maglev-assembler-arm64-inl.h
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@ -150,6 +150,22 @@ inline void PushIteratorReverse(MaglevAssembler* masm,
}
}
template <typename Arg1, typename Arg2>
inline void PushAligned(MaglevAssembler* masm, Arg1 arg1, Arg2 arg2) {
{
// Push the first argument together with padding to ensure alignment.
// The second argument is not pushed together with the first so we can
// re-use any scratch registers used to materialise the first argument for
// the second one.
UseScratchRegisterScope temps(masm);
masm->MacroAssembler::Push(ToRegister(masm, &temps, arg1), padreg);
}
{
UseScratchRegisterScope temps(masm);
masm->MacroAssembler::str(ToRegister(masm, &temps, arg2), MemOperand(sp));
}
}
template <typename Arg>
struct PushAllHelper<Arg> {
static void Push(MaglevAssembler* masm, Arg arg) {
@ -176,11 +192,7 @@ struct PushAllHelper<Arg1, Arg2, Args...> {
} else if constexpr (is_iterator_range<Arg2>::value) {
if (arg2.begin() != arg2.end()) {
auto val = *arg2.begin();
{
UseScratchRegisterScope temps(masm);
masm->MacroAssembler::Push(ToRegister(masm, &temps, arg1),
ToRegister(masm, &temps, val));
}
PushAligned(masm, arg1, val);
PushAll(masm,
base::make_iterator_range(std::next(arg2.begin()), arg2.end()),
args...);
@ -188,11 +200,7 @@ struct PushAllHelper<Arg1, Arg2, Args...> {
PushAll(masm, arg1, args...);
}
} else {
{
UseScratchRegisterScope temps(masm);
masm->MacroAssembler::Push(ToRegister(masm, &temps, arg1),
ToRegister(masm, &temps, arg2));
}
PushAligned(masm, arg1, arg2);
PushAll(masm, args...);
}
}
@ -207,21 +215,13 @@ struct PushAllHelper<Arg1, Arg2, Args...> {
masm,
base::make_iterator_range(std::next(arg2.begin()), arg2.end()),
args...);
{
UseScratchRegisterScope temps(masm);
masm->MacroAssembler::Push(ToRegister(masm, &temps, val),
ToRegister(masm, &temps, arg1));
}
PushAligned(masm, val, arg1);
} else {
PushAllReverse(masm, arg1, args...);
}
} else {
PushAllReverse(masm, args...);
{
UseScratchRegisterScope temps(masm);
masm->MacroAssembler::Push(ToRegister(masm, &temps, arg2),
ToRegister(masm, &temps, arg1));
}
PushAligned(masm, arg2, arg1);
}
}
};