diff options
Diffstat (limited to 'chapter25/src/main/java/com/seaofnodes')
| -rw-r--r-- | chapter25/src/main/java/com/seaofnodes/simple/node/ScopeNode.java | 12 |
1 files changed, 10 insertions, 2 deletions
diff --git a/chapter25/src/main/java/com/seaofnodes/simple/node/ScopeNode.java b/chapter25/src/main/java/com/seaofnodes/simple/node/ScopeNode.java index 7fb84394..527d3395 100644 --- a/chapter25/src/main/java/com/seaofnodes/simple/node/ScopeNode.java +++ b/chapter25/src/main/java/com/seaofnodes/simple/node/ScopeNode.java @@ -525,7 +525,7 @@ public class ScopeNode extends MemMergeNode { // values to Guard post-test. public void addGuards( CFGNode ctrl, Node pred, boolean invert ) { - _guards.add(ctrl); // Marker to distinguish 0,1,2 guards + _guards.add(ctrl); // Marker between guard sets // add pred & its cast to the normal input list, with special Vars if( pred==null || pred.isDead() ) return; // Dead, do not add any guards @@ -538,6 +538,14 @@ public class ScopeNode extends MemMergeNode { CFGNode early = CFGNode.earlyCFG(pred); if( early != null && !early.dominates(ctrl,null) ) return; + // A single negation is handled below. For !!p (including p != null) + // or a negated short-circuit Phi, also discover the underlying facts. + if( pred instanceof NotNode not && + (not.in(1) instanceof NotNode || not.in(1) instanceof PhiNode) ) { + pred.keep(); // Recursive peepholes may rediscover this Not. + _addGuards(ctrl,not.in(1),!invert); + pred.unkeep(); + } // Short-circuit logic is represented by a Phi. For `a || b` being // false, or `a && b` being true, both individual operands have the // same proven value as the whole expression. The "skipped RHS" path @@ -594,7 +602,7 @@ public class ScopeNode extends MemMergeNode { // Remove matching pred/cast pairs from this guarded region. public void removeGuards( Node ctrl ) { assert ctrl instanceof CFGNode; - // 0,1 or 2 guards + // Pop the guards up to this region's marker. while( true ) { Node g = _guards.pop(); if( g == ctrl ) break; |