stan/jdk-24
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

6889300: assert(i != k || is_new || i->outcnt() > 0, "don't return dead nodes")

Browse Source 
PhiNode::Ideal() should return TOP for Phi node with no users.

Reviewed-by: never, jrose
This commit is contained in:
Vladimir Kozlov 2009-10-13 22:32:31 -07:00
parent 9a22acef05
commit 998bcbaf4b
2 changed files with 12 additions and 3 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

11
hotspot/src/share/vm/opto/cfgnode.cpp
View File

@ -1531,6 +1531,8 @@ Node *PhiNode::Ideal(PhaseGVN *phase, bool can_reshape) {
return NULL; // No change
Node *top = phase->C->top();
bool new_phi = (outcnt() == 0); // transforming new Phi
assert(!can_reshape || !new_phi, "for igvn new phi should be hooked");
// The are 2 situations when only one valid phi's input is left
// (in addition to Region input).
@ -1550,6 +1552,12 @@ Node *PhiNode::Ideal(PhaseGVN *phase, bool can_reshape) {
}
}
if (can_reshape && outcnt() == 0) {
// set_req() above may kill outputs if Phi is referenced
// only by itself on the dead (top) control path.
return top;
}
Node* uin = unique_input(phase);
if (uin == top) { // Simplest case: no alive inputs.
if (can_reshape) // IGVN transformation
@ -1684,8 +1692,7 @@ Node *PhiNode::Ideal(PhaseGVN *phase, bool can_reshape) {
// Equivalent code is in MemNode::Ideal_common
Node *m = phase->transform(n);
if (outcnt() == 0) { // Above transform() may kill us!
progress = phase->C->top();
break;
return top;
}
// If transformed to a MergeMem, get the desired slice
// Otherwise the returned node represents memory for every slice

4
hotspot/src/share/vm/opto/ifnode.cpp
View File

@ -240,13 +240,13 @@ static Node* split_if(IfNode *iff, PhaseIterGVN *igvn) {
// as a single huge transform.
igvn->register_new_node_with_optimizer( region_c );
igvn->register_new_node_with_optimizer( region_x );
phi_x = phase->transform( phi_x );
// Prevent the untimely death of phi_x. Currently he has no uses. He is
// about to get one. If this only use goes away, then phi_x will look dead.
// However, he will be picking up some more uses down below.
Node *hook = new (igvn->C, 4) Node(4);
hook->init_req(0, phi_x);
hook->init_req(1, phi_c);
phi_x = phase->transform( phi_x );
// Make the compare
Node *cmp_c = phase->makecon(t);
@ -322,6 +322,7 @@ static Node* split_if(IfNode *iff, PhaseIterGVN *igvn) {
phi_s = PhiNode::make_blank(region_s,phi);
phi_s->init_req( 1, phi_c );
phi_s->init_req( 2, phi_x );
hook->add_req(phi_s);
phi_s = phase->transform(phi_s);
}
proj_path_data = phi_s;
@ -333,6 +334,7 @@ static Node* split_if(IfNode *iff, PhaseIterGVN *igvn) {
phi_f = PhiNode::make_blank(region_f,phi);
phi_f->init_req( 1, phi_c );
phi_f->init_req( 2, phi_x );
hook->add_req(phi_f);
phi_f = phase->transform(phi_f);
}
proj_path_data = phi_f;