8060036: C2: CmpU nodes can end up with wrong type information
Summary: CmpU needs to be reprocessed by CCP when an AddI/SubI input's input type change
Reviewed-by: mcberg, kvn, roland
Contributed-by: andreas.eriksson@oracle.com
--- a/hotspot/src/share/vm/opto/phaseX.cpp Thu May 21 13:54:07 2015 +0200
+++ b/hotspot/src/share/vm/opto/phaseX.cpp Thu May 21 16:49:11 2015 +0200
@@ -1573,11 +1573,12 @@
set_type(n, t);
for (DUIterator_Fast imax, i = n->fast_outs(imax); i < imax; i++) {
Node* m = n->fast_out(i); // Get user
- if( m->is_Region() ) { // New path to Region? Must recheck Phis too
+ if (m->is_Region()) { // New path to Region? Must recheck Phis too
for (DUIterator_Fast i2max, i2 = m->fast_outs(i2max); i2 < i2max; i2++) {
Node* p = m->fast_out(i2); // Propagate changes to uses
- if( p->bottom_type() != type(p) ) // If not already bottomed out
+ if (p->bottom_type() != type(p)) { // If not already bottomed out
worklist.push(p); // Propagate change to user
+ }
}
}
// If we changed the receiver type to a call, we need to revisit
@@ -1587,12 +1588,31 @@
if (m->is_Call()) {
for (DUIterator_Fast i2max, i2 = m->fast_outs(i2max); i2 < i2max; i2++) {
Node* p = m->fast_out(i2); // Propagate changes to uses
- if (p->is_Proj() && p->as_Proj()->_con == TypeFunc::Control && p->outcnt() == 1)
+ if (p->is_Proj() && p->as_Proj()->_con == TypeFunc::Control && p->outcnt() == 1) {
worklist.push(p->unique_out());
+ }
}
}
- if( m->bottom_type() != type(m) ) // If not already bottomed out
+ if (m->bottom_type() != type(m)) { // If not already bottomed out
worklist.push(m); // Propagate change to user
+ }
+
+ // CmpU nodes can get their type information from two nodes up in the
+ // graph (instead of from the nodes immediately above). Make sure they
+ // are added to the worklist if nodes they depend on are updated, since
+ // they could be missed and get wrong types otherwise.
+ uint m_op = m->Opcode();
+ if (m_op == Op_AddI || m_op == Op_SubI) {
+ for (DUIterator_Fast i2max, i2 = m->fast_outs(i2max); i2 < i2max; i2++) {
+ Node* p = m->fast_out(i2); // Propagate changes to uses
+ if (p->Opcode() == Op_CmpU) {
+ // Got a CmpU which might need the new type information from node n.
+ if(p->bottom_type() != type(p)) { // If not already bottomed out
+ worklist.push(p); // Propagate change to user
+ }
+ }
+ }
+ }
}
}
}