From 8944e27762712679e50962598ed1be8dc1fbe7be Mon Sep 17 00:00:00 2001
From: Mike Pall <mike>
Date: Sat, 26 Oct 2013 17:31:23 +0200
Subject: Fix handling of redundant PHIs.
---
src/lj_opt_loop.c | 31 +++++++++++++++----------------
1 file changed, 15 insertions(+), 16 deletions(-)
(limited to 'src')
diff --git a/src/lj_opt_loop.c b/src/lj_opt_loop.c
index 3a119f47..fa5e03e4 100644
--- a/src/lj_opt_loop.c
+++ b/src/lj_opt_loop.c
@@ -105,20 +105,24 @@ static void loop_emit_phi(jit_State *J, IRRef1 *subst, IRRef1 *phi, IRRef nphi,
SnapNo onsnap)
{
int passx = 0;
- IRRef i, nslots;
+ IRRef i, j, nslots;
IRRef invar = J->chain[IR_LOOP];
/* Pass #1: mark redundant and potentially redundant PHIs. */
- for (i = 0; i < nphi; i++) {
+ for (i = 0, j = 0; i < nphi; i++) {
IRRef lref = phi[i];
IRRef rref = subst[lref];
if (lref == rref || rref == REF_DROP) { /* Invariants are redundant. */
- irt_setmark(IR(lref)->t);
- } else if (!(IR(rref)->op1 == lref || IR(rref)->op2 == lref)) {
- /* Quick check for simple recurrences failed, need pass2. */
- irt_setmark(IR(lref)->t);
- passx = 1;
+ irt_clearphi(IR(lref)->t);
+ } else {
+ phi[j++] = (IRRef1)lref;
+ if (!(IR(rref)->op1 == lref || IR(rref)->op2 == lref)) {
+ /* Quick check for simple recurrences failed, need pass2. */
+ irt_setmark(IR(lref)->t);
+ passx = 1;
+ }
}
}
+ nphi = j;
/* Pass #2: traverse variant part and clear marks of non-redundant PHIs. */
if (passx) {
SnapNo s;
@@ -174,15 +178,10 @@ static void loop_emit_phi(jit_State *J, IRRef1 *subst, IRRef1 *phi, IRRef nphi,
IRRef lref = phi[i];
IRIns *ir = IR(lref);
if (!irt_ismarked(ir->t)) { /* Propagate only from unmarked PHIs. */
- IRRef rref = subst[lref];
- if (lref == rref) { /* Mark redundant PHI. */
- irt_setmark(ir->t);
- } else {
- IRIns *irr = IR(rref);
- if (irt_ismarked(irr->t)) { /* Right ref points to other PHI? */
- irt_clearmark(irr->t); /* Mark that PHI as non-redundant. */
- passx = 1; /* Retry. */
- }
+ IRIns *irr = IR(subst[lref]);
+ if (irt_ismarked(irr->t)) { /* Right ref points to other PHI? */
+ irt_clearmark(irr->t); /* Mark that PHI as non-redundant. */
+ passx = 1; /* Retry. */
}
}
}
--
cgit v1.2.3-55-g6feb