diff options
Diffstat (limited to 'chapter15/src/main/java/com/seaofnodes')
6 files changed, 49 insertions, 43 deletions
diff --git a/chapter15/src/main/java/com/seaofnodes/simple/GlobalCodeMotion.java b/chapter15/src/main/java/com/seaofnodes/simple/GlobalCodeMotion.java index 27f69c42..27307d32 100644 --- a/chapter15/src/main/java/com/seaofnodes/simple/GlobalCodeMotion.java +++ b/chapter15/src/main/java/com/seaofnodes/simple/GlobalCodeMotion.java @@ -69,6 +69,15 @@ public abstract class GlobalCodeMotion { cfg.loopDepth(); for( Node n : cfg._inputs ) _schedEarly(n,visit); + // In dead infinite loops, entire code blocks may be unreachable + // from below. Reach down from the CFG to their Phis so their + // inputs are scheduled too. + if( cfg instanceof RegionNode ) { + int len = cfg.nOuts(); + for( int i=0; i<len; i++ ) + if( cfg.out(i) instanceof PhiNode phi ) + _schedEarly(phi,visit); + } } } @@ -86,20 +95,17 @@ public abstract class GlobalCodeMotion { if( n==null || visit.get(n._nid) ) return; // Been there, done that assert !(n instanceof CFGNode); visit.set(n._nid); - // Schedule not-pinned not-CFG inputs before self. Since skipping - // Pinned, this never walks the backedge of Phis (and thus spins around - // a data-only loop, eventually attempting relying on some pre-visited- - // not-post-visited data op with no scheduled control. + // Schedule inputs first, except Phis: following their backedges would + // enter a data cycle before its control has been scheduled. for( Node def : n._inputs ) if( def!=null ) _schedEarly(def,visit); - // If not-pinned (e.g. constants, projections, phi) and not-CFG - if( !n.isPinned() ) { + // An existing edge 0 already supplies control (or a Phi/Proj binding). + if( n.in(0)==null ) { // Schedule at deepest input CFGNode early = Parser.START; // Maximally early, lowest idepth - if( n.in(0) instanceof CFGNode cfg ) early = cfg; for( int i=1; i<n.nIns(); i++ ) - if( n.in(i).cfg0().idepth() > early.idepth() ) + if( n.in(i)!=null && n.in(i).cfg0().idepth() > early.idepth() ) early = n.in(i).cfg0(); // Latest/deepest input n.setDef(0,early); // First place this can go } @@ -109,8 +115,11 @@ public abstract class GlobalCodeMotion { private static void schedLate( StopNode stop) { CFGNode[] late = new CFGNode[Node.UID()]; Node[] ns = new Node[Node.UID()]; + // Record Load NIDs at all their CFG block choices, then check against + // Store block choices to force a Load above an anti-dependent Store. + int[] anti = new int[Node.UID()]; // Breadth-first scheduling - breadth(stop,ns,late); + breadth(stop,ns,late,anti); // Copy the best placement choice into the control slot for( int i=0; i<late.length; i++ ) @@ -118,7 +127,7 @@ public abstract class GlobalCodeMotion { ns[i].setDef(0,late[i]); } - private static void breadth(Node stop, Node[] ns, CFGNode[] late) { + private static void breadth(Node stop, Node[] ns, CFGNode[] late, int[] anti) { // Things on the worklist have some (but perhaps not all) uses done. WorkList<Node> work = new WorkList<>(); work.push(stop); @@ -148,22 +157,26 @@ public abstract class GlobalCodeMotion { continue outer; // All uses done, schedule - _doSchedLate(n,ns,late); + _doSchedLate(n,ns,late,anti); } - // Walk all inputs and put on worklist, as their last-use might now be done - for( Node def : n._inputs ) - if( def!=null && late[def._nid]==null ) { - work.push(def); - // if the def has a load use, maybe the load can fire - for( Node ld : def._outputs ) - if( ld instanceof LoadNode && late[ld._nid]==null ) - work.push(ld); - } + // A use just finished; reconsider its inputs and waiting loads, + // even when the shared memory input was already scheduled. + for( Node def : n._inputs ) { + if( def==null ) continue; + if( late[def._nid]==null ) work.push(def); + for( Node out : def._outputs ) + if( out instanceof LoadNode ld && late[ld._nid]==null ) + work.push(ld); + } + if( n instanceof LoopNode loop ) + for( Node phi : loop._outputs ) + if( phi instanceof PhiNode && late[phi._nid]==null ) + work.push(phi); } } - private static void _doSchedLate(Node n, Node[] ns, CFGNode[] late) { + private static void _doSchedLate(Node n, Node[] ns, CFGNode[] late, int[] anti) { // Walk uses, gathering the LCA (Least Common Ancestor) of uses CFGNode early = n.in(0) instanceof CFGNode cfg ? cfg : n.in(0).cfg0(); assert early != null; @@ -174,7 +187,7 @@ public abstract class GlobalCodeMotion { // Loads may need anti-dependencies, raising their LCA if( n instanceof LoadNode load ) - lca = find_anti_dep(lca,load,early,late); + lca = find_anti_dep(lca,load,early,late,anti); // Walk up from the LCA to the early, looking for best place. This is // the lowest execution frequency, approximated by least loop depth and @@ -197,8 +210,7 @@ public abstract class GlobalCodeMotion { CFGNode found=null; for( int i=1; i<phi.nIns(); i++ ) if( phi.in(i)==n ) - if( found==null ) found = phi.region().cfg(i); - else Utils.TODO(); // Can be more than once + found = phi.region().cfg(i).domLCA(found,null); // Can be more than one matching input. assert found!=null; return found; } @@ -206,32 +218,34 @@ public abstract class GlobalCodeMotion { // Least loop depth first, then largest idepth private static boolean better( CFGNode lca, CFGNode best ) { - return lca._loopDepth < best._loopDepth || - (lca.idepth() > best.idepth() || best instanceof IfNode); + return lca.loopDepth() < best.loopDepth() || + lca instanceof NeverNode || + lca.idepth() > best.idepth() || + best instanceof IfNode; } - private static CFGNode find_anti_dep(CFGNode lca, LoadNode load, CFGNode early, CFGNode[] late) { + private static CFGNode find_anti_dep(CFGNode lca, LoadNode load, CFGNode early, CFGNode[] late, int[] anti) { // We could skip final-field loads here. // Walk LCA->early, flagging Load's block location choices for( CFGNode cfg=lca; early!=null && cfg!=early.idom(); cfg = cfg.idom() ) - cfg._anti = load._nid; + anti[cfg._nid] = load._nid; // Walk load->mem uses, looking for Stores causing an anti-dep for( Node mem : load.mem()._outputs ) { switch( mem ) { case StoreNode st: assert late[st._nid]!=null; - lca = anti_dep(load,late[st._nid],st.cfg0(),lca,st); + lca = anti_dep(load,late[st._nid],st.cfg0(),lca,st,anti); break; case NewNode st: assert late[st._nid]!=null; - lca = anti_dep(load,late[st._nid],st.cfg0(),lca,st); + lca = anti_dep(load,late[st._nid],st.cfg0(),lca,st,anti); break; case PhiNode phi: // Repeat anti-dep for matching Phi inputs. // No anti-dep edges but may raise the LCA. for( int i=1; i<phi.nIns(); i++ ) if( phi.in(i)==load.mem() ) - lca = anti_dep(load,phi.region().cfg(i),load.mem().cfg0(),lca,null); + lca = anti_dep(load,phi.region().cfg(i),load.mem().cfg0(),lca,null,anti); break; case LoadNode ld: break; // Loads do not cause anti-deps on other loads case ReturnNode ret: break; // Load must already be ahead of Return @@ -243,11 +257,12 @@ public abstract class GlobalCodeMotion { } // - private static CFGNode anti_dep( LoadNode load, CFGNode stblk, CFGNode defblk, CFGNode lca, Node st ) { - // Walk store blocks "reach" from its scheduled location to its earliest + private static CFGNode anti_dep( LoadNode load, CFGNode stblk, CFGNode defblk, CFGNode lca, Node st, int[] anti ) { + // Preserve the full store range for the earlier evaluator scheduler. + // It places nodes independently of GCM and may hoist this store. for( ; stblk != defblk.idom(); stblk = stblk.idom() ) { // Store and Load overlap, need anti-dependence - if( stblk._anti==load._nid ) { + if( anti[stblk._nid]==load._nid ) { lca = stblk.domLCA(lca,null); // Raise Loads LCA if( lca == stblk && st != null && Utils.find(st._inputs,load) == -1 ) // And if something moved, st.addDef(load); // Add anti-dep as well diff --git a/chapter15/src/main/java/com/seaofnodes/simple/node/CFGNode.java b/chapter15/src/main/java/com/seaofnodes/simple/node/CFGNode.java index 704dea8d..06596ce0 100644 --- a/chapter15/src/main/java/com/seaofnodes/simple/node/CFGNode.java +++ b/chapter15/src/main/java/com/seaofnodes/simple/node/CFGNode.java @@ -75,9 +75,6 @@ public abstract class CFGNode extends Node { public int _loopDepth; public int loopDepth() { return _loopDepth==0 ? (_loopDepth = cfg(0).loopDepth()) : _loopDepth; } - // Anti-dependence field support - public int _anti; // Per-CFG field to help find anti-deps - // ------------------------------------------------------------------------ // Support routines for Global Code Motion diff --git a/chapter15/src/main/java/com/seaofnodes/simple/node/CastNode.java b/chapter15/src/main/java/com/seaofnodes/simple/node/CastNode.java index fbf0e518..38d6a126 100644 --- a/chapter15/src/main/java/com/seaofnodes/simple/node/CastNode.java +++ b/chapter15/src/main/java/com/seaofnodes/simple/node/CastNode.java @@ -21,8 +21,6 @@ public class CastNode extends Node { @Override public String uniqueName() { return "Cast_" + _nid; } - @Override - public boolean isPinned() { return true; } @Override StringBuilder _print1(StringBuilder sb, BitSet visited) { diff --git a/chapter15/src/main/java/com/seaofnodes/simple/node/Node.java b/chapter15/src/main/java/com/seaofnodes/simple/node/Node.java index 7c22a50e..b65630bb 100644 --- a/chapter15/src/main/java/com/seaofnodes/simple/node/Node.java +++ b/chapter15/src/main/java/com/seaofnodes/simple/node/Node.java @@ -535,8 +535,6 @@ public abstract class Node implements OutNode { /** Return block start from a isCFG() */ public Node getBlockStart() { return null; } - /** Pinned in the schedule; these are data nodes whose input#0 is not allowed to change */ - public boolean isPinned() { return false; } // Semantic change to the graph (so NOT a peephole), used by the Parser. // If any input is a float, flip to a float-flavored opcode and widen any diff --git a/chapter15/src/main/java/com/seaofnodes/simple/node/PhiNode.java b/chapter15/src/main/java/com/seaofnodes/simple/node/PhiNode.java index 139e80a3..ddca3034 100644 --- a/chapter15/src/main/java/com/seaofnodes/simple/node/PhiNode.java +++ b/chapter15/src/main/java/com/seaofnodes/simple/node/PhiNode.java @@ -38,7 +38,6 @@ public class PhiNode extends Node { public CFGNode region() { return (CFGNode)in(0); } @Override public boolean isMultiTail() { return true; } @Override public boolean isMem() { return _declaredType instanceof TypeMem; } - @Override public boolean isPinned() { return true; } @Override public Type compute() { diff --git a/chapter15/src/main/java/com/seaofnodes/simple/node/ProjNode.java b/chapter15/src/main/java/com/seaofnodes/simple/node/ProjNode.java index 73c1fa15..cd57b85c 100644 --- a/chapter15/src/main/java/com/seaofnodes/simple/node/ProjNode.java +++ b/chapter15/src/main/java/com/seaofnodes/simple/node/ProjNode.java @@ -29,7 +29,6 @@ public class ProjNode extends Node { @Override public boolean isMultiTail() { return in(0).isMultiHead(); } @Override public boolean isMem() { return _type instanceof TypeMem; } - @Override public boolean isPinned() { return true; } @Override public Type compute() { |