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soften heuristic of 316b57

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Instead of systematically spilling any
temp live in an exit branch but not in
the part of the loop already processed,
only spill when it is already known to
have been spilled.
This commit is contained in:
Quentin Carbonneaux 2019-02-06 09:09:03 +01:00
parent ce0ab53ed7
commit d9b0d77cf2
1 changed files with 15 additions and 4 deletions
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19
spill.c
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@ -280,6 +280,19 @@ dopm(Blk *b, Ins *i, BSet *v)
return i;
}
static void
merge(BSet *u, Blk *bu, BSet *v, Blk *bv)
{
int t;
if (bu->loop <= bv->loop)
bsunion(u, v);
else
for (t=0; bsiter(v, &t); t++)
if (tmp[t].slot == -1)
bsset(u, t);
}
/* spill code insertion
* requires spill costs, rpo, liveness
*
@ -364,12 +377,10 @@ spill(Fn *fn)
* in the middle of loops */
bszero(v);
liveon(w, b, s1);
if (s1->loop >= b->loop)
bsunion(v, w);
merge(v, b, w, s1);
if (s2) {
liveon(u, b, s2);
if (s2->loop >= b->loop)
bsunion(v, u);
merge(v, b, u, s2);
bsinter(w, u);
}
limit2(v, 0, 0, w);