On Tue, 14 Jul 2015, Richard Biener wrote:
> On Mon, 13 Jul 2015, Jeff Law wrote:
>
> > > 2015-07-13 Richard Biener <rguent...@suse.de>
> > >
> > > * tree-ssa-dom.c (record_temporary_equivalences): Merge
> > > wideing type conversion case from
> > > record_equivalences_from_incoming_edge
> > > and use record_equality to record equivalences.
> > > (record_equivalences_from_incoming_edge): Call
> > > record_temporary_equivalences.
> > Yea, if testing is clean, that's OK. Ought to be easier to then add code to
> > handle looking at the uses of X to see if they create an equivalence for the
> > destination of those use statements.
>
> Applied. The following patch adds the equivalences for the destination
> of use stmts if they simplify.
Actually I can't use FOR_EACH_IMM_USE_STMT any longer because
record_equivalence ends up calling has_single_use which doens't
handle the special marker FOR_EACH_IMM_USE_STMT inserts.
Thus the following - bootstrapped and tested on x86_64-unknown-linux-gnu.
Ok?
Thanks,
Richard.
2015-07-14 Richard Biener <rguent...@suse.de>
* tree-ssa-dom.c (dom_valueize): New function.
(record_temporary_equivalences): Also record equivalences
for dominating stmts that have uses of equivalences we are
about to record.
Index: gcc/tree-ssa-dom.c
===================================================================
--- gcc/tree-ssa-dom.c (revision 225761)
+++ gcc/tree-ssa-dom.c (working copy)
@@ -1401,6 +1401,20 @@ simplify_stmt_for_jump_threading (gimple
return lookup_avail_expr (stmt, false);
}
+/* Valueize hook for gimple_fold_stmt_to_constant_1. */
+
+static tree
+dom_valueize (tree t)
+{
+ if (TREE_CODE (t) == SSA_NAME)
+ {
+ tree tem = SSA_NAME_VALUE (t);
+ if (tem)
+ return tem;
+ }
+ return t;
+}
+
/* Record into the equivalence tables any equivalences implied by
traversing edge E (which are cached in E->aux).
@@ -1428,7 +1442,6 @@ record_temporary_equivalences (edge e)
additional equivalences. */
if (lhs
&& TREE_CODE (lhs) == SSA_NAME
- && is_gimple_constant (rhs)
&& TREE_CODE (rhs) == INTEGER_CST)
{
gimple defstmt = SSA_NAME_DEF_STMT (lhs);
@@ -1455,6 +1468,41 @@ record_temporary_equivalences (edge e)
}
}
}
+
+ /* If LHS is an SSA_NAME with a new equivalency then try if
+ stmts with uses of that LHS that dominate the edge destination
+ simplify and allow further equivalences to be recorded. */
+ if (lhs && TREE_CODE (lhs) == SSA_NAME)
+ {
+ use_operand_p use_p;
+ imm_use_iterator iter;
+ FOR_EACH_IMM_USE_FAST (use_p, iter, lhs)
+ {
+ gimple use_stmt = USE_STMT (use_p);
+
+ /* Only bother to record more equivalences for lhs that
+ can be directly used by e->dest.
+ ??? If the code gets re-organized to a worklist to
+ catch more indirect opportunities and it is made to
+ handle PHIs then this should only consider use_stmts
+ in basic-blocks we have already visited. */
+ if (e->dest == gimple_bb (use_stmt)
+ || !dominated_by_p (CDI_DOMINATORS,
+ e->dest, gimple_bb (use_stmt)))
+ continue;
+ tree lhs2 = gimple_get_lhs (use_stmt);
+ if (lhs2 && TREE_CODE (lhs2) == SSA_NAME)
+ {
+ tree res
+ = gimple_fold_stmt_to_constant_1 (use_stmt, dom_valueize,
+ no_follow_ssa_edges);
+ if (res
+ && (TREE_CODE (res) == SSA_NAME
+ || is_gimple_min_invariant (res)))
+ record_equality (lhs2, res);
+ }
+ }
+ }
/* If we have 0 = COND or 1 = COND equivalences, record them
into our expression hash tables. */
