diff options
Diffstat (limited to 'chapter22')
| -rw-r--r-- | chapter22/src/main/java/com/seaofnodes/simple/codegen/GlobalCodeMotion.java | 25 | ||||
| -rw-r--r-- | chapter22/src/test/java/com/seaofnodes/simple/Chapter21Test.java | 18 |
2 files changed, 33 insertions, 10 deletions
diff --git a/chapter22/src/main/java/com/seaofnodes/simple/codegen/GlobalCodeMotion.java b/chapter22/src/main/java/com/seaofnodes/simple/codegen/GlobalCodeMotion.java index 21a8ad76..530336d6 100644 --- a/chapter22/src/main/java/com/seaofnodes/simple/codegen/GlobalCodeMotion.java +++ b/chapter22/src/main/java/com/seaofnodes/simple/codegen/GlobalCodeMotion.java @@ -266,22 +266,22 @@ public abstract class GlobalCodeMotion { switch( mem ) { case MemOpNode st: assert late[st._nid]!=null; - lca = anti_dep(load,late[st._nid],lca,st,anti); + lca = anti_dep(load,late[st._nid],st.cfg0(),lca,st,anti); break; case CallNode st: assert late[st._nid]!=null; - lca = anti_dep(load,late[st._nid],lca,st,anti); + 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),lca,null,anti); + lca = anti_dep(load,phi.region().cfg(i),load.mem().cfg0(),lca,null,anti); break; case NewNode st: assert late[st._nid]!=null; - lca = anti_dep(load,late[st._nid],lca,st,anti); + lca = anti_dep(load,late[st._nid],st.cfg0(),lca,st,anti); break; default: throw Utils.TODO(); } @@ -290,12 +290,17 @@ public abstract class GlobalCodeMotion { } // - private static CFGNode anti_dep( MemOpNode load, CFGNode stblk, CFGNode lca, Node st, int[] anti ) { - // Stores are already placed. Constrain the load at that block only. - if( anti[stblk._nid]==load._nid ) { - lca = stblk.domLCA(lca,null); - if( lca==stblk && st!=null && !(st instanceof CallNode) && st._inputs.find(load) == -1 ) - st.addDef(load); // Same-block load must precede the store. + private static CFGNode anti_dep( MemOpNode load, CFGNode stblk, CFGNode defblk, CFGNode lca, Node st, int[] anti ) { + // A conditional writer can precede the load without dominating its late block. + // Walk back to the first overlap with the load's placement range. + for( ; stblk != defblk.idom(); stblk = stblk.idom() ) { + // Store and Load overlap, need anti-dependence + if( anti[stblk._nid]==load._nid ) { + lca = stblk.domLCA(lca,null); // Raise Loads LCA + if( lca == stblk && st != null && !(st instanceof CallNode) && st._inputs.find(load) == -1 ) // And if something moved, + st.addDef(load); // Add anti-dep as well; Calls already end their block. + return lca; // Cap this stores' anti-dep to here + } } return lca; } diff --git a/chapter22/src/test/java/com/seaofnodes/simple/Chapter21Test.java b/chapter22/src/test/java/com/seaofnodes/simple/Chapter21Test.java index 926acf93..a52cb80b 100644 --- a/chapter22/src/test/java/com/seaofnodes/simple/Chapter21Test.java +++ b/chapter22/src/test/java/com/seaofnodes/simple/Chapter21Test.java @@ -17,6 +17,24 @@ import static org.junit.Assert.*; public class Chapter21Test { + @Test public void testReadBeforeConditionalStore() { + var code = new CodeGen(""" + struct S { int x; }; S !a=new S; S !b=new S; + a.x=10; b.x=20; S !p=a; if(arg&1) p=b; + int sum=0; + for(int i=0; i<6; i++) { + sum+=a.x; + if(i==2) p.x=30; + else if(i==4) b.x=40; + } + return sum; + """).parse().opto(); + // The i==2 read still sees 10: three reads of 10, then three of 30. + assertEquals("120",Eval2.eval(code,0)); + assertEquals("60",Eval2.eval(code,1)); + } + + @Test public void testArmBitfieldExtracts() { // Independent SXT/UXT instruction words, plus ASR, LSR and LSL aliases. int[] ops = {0x93401c20,0xd3401c20,0x93403c20,0xd3403c20, |