Use sets instead of hashamps for the spillmaps (attempt #2)#304
Merged
ltratt merged 1 commit intoykjit:mainfrom Feb 2, 2026
Merged
Use sets instead of hashamps for the spillmaps (attempt #2)#304ltratt merged 1 commit intoykjit:mainfrom
ltratt merged 1 commit intoykjit:mainfrom
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Merged
|
At some points this PR says "should" but I don't know if that means "can if you want" or "absolutely must". Can we force push a change which clarifies what is meant (i.e. avoiding the most dangerous word in the English language :p). |
The spillmap analysis has been a consistent source of bugs, mostly (in
my opinion) due to the choice of data structures.
This change moves from a hashmap-centric representation to a set-based
one. This is much less error prone and easier to understand than our
previous hashmap-based method. It's also more compact.
For example, before if we had:
{
rax -> {rbx, rcx},
rbx -> {rax, rcx},
rcx -> {rax, rbx},
r11 -> {rbp-16},
// no `rbp-16 -> {r11}` because hashmap keyed by register!
}
Now it is stored as:
[
{rax, rbx, rcx},
{r11, rbp-16}
]
This fixes some broken benchmarks in an upcoming optimisation branch I
have locally.
Author
|
Force pushed. If it looks OK I'll re-sync the yk-side. |
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The spillmap analysis has been a consistent source of bugs, mostly (in my opinion) due to the choice of data structures.
This change moves from a hashmap-centric representation to a set-based one. This is much less error prone and easier to understand than our previous hashmap-based method. It's also more compact.
For example, before if we had:
{
rax -> {rbx, rcx},
rbx -> {rax, rcx},
rcx -> {rax, rbx},
r11 -> {rbp-16},
// no
rbp-16 -> {r11}because hashmap keyed by register!}
Now it is stored as:
[
{rax, rbx, rcx},
{r11, rbp-16}
]
This fixes some broken benchmarks in an upcoming optimisation branch I have locally.