MonetDB: Feb2013 - Compact dataflow removal

[Martin Kersten]

Changeset: 9d51e0959690 for MonetDB
URL: http://dev.monetdb.org/hg/MonetDB?cmd=changeset;node=9d51e0959690
Modified Files:
        monetdb5/optimizer/opt_dataflow.c
        monetdb5/optimizer/opt_dataflow.h
Branch: Feb2013
Log Message:

Compact dataflow removal
Removal of the dataflow instructions is removed from the main call.
It is better to leave it to the other optimizers to remove them
using removeDataflow(), for it reduces the cost in > 95% of the cases.


diffs (76 lines):

diff --git a/monetdb5/optimizer/opt_dataflow.c 
b/monetdb5/optimizer/opt_dataflow.c
--- a/monetdb5/optimizer/opt_dataflow.c
+++ b/monetdb5/optimizer/opt_dataflow.c
@@ -62,10 +62,15 @@ simpleFlow(InstrPtr *old, int start, int
        return 1;
 }
 
-void removeDataflow(InstrPtr *old, int limit)
+/* optimizers may remove the dataflow hints first */
+void removeDataflow(MalBlkPtr mb, InstrPtr *old, int limit)
 {
-       int i, flowblock=0;
+       int i, j, k, flowblock=0;
        InstrPtr p;
+       int *init= GDKzalloc(mb->vtop * sizeof(int)), skip = 0;
+
+       if ( init == 0)
+               return;
        /* remove the inlined dataflow barriers */
        for (i = 1; i<limit; i++) {
                p = old[i];
@@ -80,8 +85,33 @@ void removeDataflow(InstrPtr *old, int l
                        flowblock = 0;
                        freeInstruction(p);
                        old[i] = NULL;
+               } else {
+                       /* remember first initialization */
+                       if ( p->argc == 2 && isVarConstant(mb,getArg(p,1))  && 
init[getArg(p,0)] == 0)
+                               init[getArg(p,0)] = i;
+                       if( blockStart(p) && !skip)
+                               skip++;
                }
        }
+       /* remove the superflous variable initializations */
+       /* when there are no auxillary barrier blocks */
+       if ( !skip)
+       for (i = 1; i<limit; i++) {
+               p = old[i];
+               if ( p && init[ j = getArg(p,0)]  != i  &&  j && old[init[j]] 
== 0){
+                       /* check for self-use in second assignment */
+                       for ( k = p->retc; k < p->argc; k++)
+                               if ( getArg(p,k) == getArg(p,0) )
+                                       break;
+                       if ( k == p->argc) {
+                               freeInstruction( old[init[j]]);
+                               old[j] = NULL;
+                       }
+                       /* ignore further */
+                       init[j] = 0;
+               } 
+       }
+       GDKfree(init);
 }
 
 static int
@@ -223,7 +253,7 @@ OPTdataflowImplementation(Client cntxt, 
        }
        pushInstruction(mb,old[0]);
 
-       removeDataflow(old,limit);
+       //removeDataflow(mb, old,limit); To be done explicit by optimizers
 
        /* inject new dataflow barriers */
        for (i = 1; i<limit; i++) {
diff --git a/monetdb5/optimizer/opt_dataflow.h 
b/monetdb5/optimizer/opt_dataflow.h
--- a/monetdb5/optimizer/opt_dataflow.h
+++ b/monetdb5/optimizer/opt_dataflow.h
@@ -24,7 +24,7 @@
 #include "opt_support.h"
 
 #define OPTDEBUGdataflow  if ( optDebug & (1 <<DEBUG_OPT_DATAFLOW) )
-opt_export void removeDataflow(InstrPtr *old, int limit);
+opt_export void removeDataflow(MalBlkPtr mb, InstrPtr *old, int limit);
 opt_export int OPTdataflowImplementation(Client cntxt, MalBlkPtr mb, MalStkPtr 
stk, InstrPtr p);
 
 #endif
_______________________________________________
checkin-list mailing list
checkin-list@monetdb.org
http://mail.monetdb.org/mailman/listinfo/checkin-list