aboutsummaryrefslogtreecommitdiff
path: root/ssa.c
diff options
context:
space:
mode:
Diffstat (limited to 'ssa.c')
-rw-r--r--ssa.c21
1 files changed, 16 insertions, 5 deletions
diff --git a/ssa.c b/ssa.c
index 7ae8117..c098438 100644
--- a/ssa.c
+++ b/ssa.c
@@ -47,6 +47,7 @@ filluse(Fn *fn)
/* todo, is this the correct file? */
tmp = fn->tmp;
for (t=Tmp0; t<fn->ntmp; t++) {
+ tmp[t].bid = -1u;
tmp[t].ndef = 0;
tmp[t].nuse = 0;
tmp[t].cls = 0;
@@ -59,6 +60,7 @@ filluse(Fn *fn)
for (p=b->phi; p; p=p->link) {
assert(rtype(p->to) == RTmp);
tp = p->to.val;
+ tmp[tp].bid = b->id;
tmp[tp].ndef++;
tmp[tp].cls = p->cls;
tp = phicls(tp, fn->tmp);
@@ -84,6 +86,7 @@ filluse(Fn *fn)
w = WFull;
t = i->to.val;
tmp[t].width = w;
+ tmp[t].bid = b->id;
tmp[t].ndef++;
tmp[t].cls = i->cls;
}
@@ -111,9 +114,10 @@ phiins(Fn *fn)
Blk *a, *b, **blist, **be, **bp;
Ins *i;
Phi *p;
+ Use *use;
Ref r;
- int t, nt;
- uint n;
+ int t, nt, ok;
+ uint n, defb;
short k;
bsinit(u, fn->nblk);
@@ -125,8 +129,15 @@ phiins(Fn *fn)
fn->tmp[t].visit = 0;
if (fn->tmp[t].phi != 0)
continue;
- if (fn->tmp[t].ndef == 1)
- continue;
+ if (fn->tmp[t].ndef == 1) {
+ ok = 1;
+ defb = fn->tmp[t].bid;
+ use = fn->tmp[t].use;
+ for (n=fn->tmp[t].nuse; n--; use++)
+ ok &= use->bid == defb;
+ if (ok || defb == fn->start->id)
+ continue;
+ }
bszero(u);
k = -1;
bp = be;
@@ -293,7 +304,7 @@ renblk(Blk *b, Name **stk, Fn *fn)
renblk(s, stk, fn);
}
-/* require rpo and ndef */
+/* require rpo and use */
void
ssa(Fn *fn)
{