Update of /cvsroot/monetdb/pathfinder/compiler/mil
In directory sc8-pr-cvs16:/tmp/cvs-serv584/mil
Modified Files:
mil_dce.c
Log Message:
-- Remove unnecessary materialize operators (the ones where the output
of the materialize operator is only consumed by either a mposjoin or
a mvaljoin).
Index: mil_dce.c
===================================================================
RCS file: /cvsroot/monetdb/pathfinder/compiler/mil/mil_dce.c,v
retrieving revision 1.13
retrieving revision 1.14
diff -u -d -r1.13 -r1.14
--- mil_dce.c 15 Mar 2007 14:12:57 -0000 1.13
+++ mil_dce.c 15 Apr 2007 19:23:51 -0000 1.14
@@ -459,6 +459,137 @@
}
/**
+ * Remove unnecessary materialize operators (the ones where the output
+ * of the materialize operator is only consumed by either a mposjoin or
+ * a mvaljoin).
+ */
+static void
+mil_materialize_elimination (PFmil_t *n,
+ PFbitset_t *used_vars,
+ bool mark_used,
+ bool change)
+{
+ assert (n);
+ switch (n->kind) {
+ case m_seq:
+ /* descend in reverse pre-order, collect the used variables
+ * from the end to beginning of the program. */
+ for (int i = MIL_MAXCHILD; --i >= 0;)
+ if (n->child[i])
+ mil_materialize_elimination (n->child[i],
+ used_vars,
+ true,
+ change);
+ break;
+
+ case m_assgn:
+ assert(n->child[0]->kind == m_var);
+
+ /* Propagate the information whether the input has to
+ be materialized or not. */
+ mil_materialize_elimination (n->child[1],
+ used_vars,
+ PFbitset_get (used_vars,
+ n->child[0]->sem.ident),
+ change);
+
+ /* The variable is unused before the assignment. */
+ PFbitset_set (used_vars, n->child[0]->sem.ident, false);
+ break;
+
+ case m_var:
+ /* mark all variables as used if they should be marked as used */
+ if (mark_used)
+ PFbitset_set (used_vars, n->sem.ident, true);
+ break;
+
+ case m_mposjoin:
+ case m_mvaljoin:
+ /* The inputs to this operators may be un-materialized */
+ for (unsigned int i = 0; i < MIL_MAXCHILD && n->child[i]; i++)
+ mil_materialize_elimination (n->child[i],
+ used_vars,
+ false,
+ change);
+ break;
+
+ case m_materialize:
+ /* remove the materialize operator if we are
+ in the change mode and it the materialize
+ operator is not marked as used */
+ if (!mark_used && change)
+ *n = *(n->child[0]);
+ break;
+
+ case m_if:
+ {
+ /*
+ * to find the used variables of a if-then-else block, we must
+ * find them for the if and for the else part and join the sets.
+ */
+ PFbitset_t *else_used_vars = PFbitset_copy (used_vars);
+
+ /* invoke recursive call on if part */
+ mil_materialize_elimination (n->child[1],
+ used_vars,
+ true,
+ change);
+
+ /* invoke recursive call on else part */
+ mil_materialize_elimination (n->child[2],
+ else_used_vars,
+ true,
+ change);
+
+ PFbitset_or (used_vars, else_used_vars);
+
+ /* the variables of the condition are required */
+ mil_materialize_elimination (n->child[0],
+ used_vars,
+ true,
+ change);
+ } break;
+
+ case m_while:
+ /* ONLY collect the variables required for an iteration */
+ mil_materialize_elimination (n->child[1],
+ used_vars,
+ true,
+ false);
+ /* the variables of the condition are required
+ for the next iteration */
+ mil_materialize_elimination (n->child[0],
+ used_vars,
+ true,
+ false);
+
+ /* invoke dce on the loop body (used_vars now contains the
+ variables in the condition as well as the ones required
+ for another pass through the body */
+ mil_materialize_elimination (n->child[1],
+ used_vars,
+ true,
+ true);
+
+ /* the variables of the condition are required for the first
+ check of the condition */
+ mil_materialize_elimination (n->child[0],
+ used_vars,
+ true,
+ true);
+ break;
+
+ default:
+ for (unsigned int i = 0; i < MIL_MAXCHILD && n->child[i]; i++)
+ mil_materialize_elimination (n->child[i],
+ used_vars,
+ true,
+ change);
+ break;
+ }
+}
+
+/**
* Peform a dead MIL code elimination.
* It reads the code from the end to the beginning of the program and
* collects the used variables, starting from the serialize, error and
@@ -482,8 +613,11 @@
{
PFbitset_t *used_vars = PFbitset ();
+ PFbitset_t *used_vars2 = PFbitset ();
PFbitset_t *dirty_vars = PFbitset ();
+ mil_materialize_elimination (root, used_vars2, true, true);
+
/* variable unused is always used because it helps MonetDB to cleanup */
PFbitset_set (used_vars, PF_MIL_VAR_UNUSED, true);
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