http://gcc.gnu.org/bugzilla/show_bug.cgi?id=52976
--- Comment #6 from William J. Schmidt <wschmidt at gcc dot gnu.org> 2012-04-14
15:05:37 UTC ---
The following patch fixes both reduced test cases and appears to fix the SPEC
problems in PR52980 as well. Bootstrap/regression test in progress, and will
then do a complete set of SPEC builds to be sure.
The second problem involved a subtlety in the rank order of operands. When
introducing the calls to __builtin_powi, I needed to fiddle with the resulting
operand rank to ensure uses of the call result appear after the call.
Dominique, please let me know whether this cleans up all your polyhedron tests
without introducing new failures. Thanks!
Index: gcc/tree-ssa-reassoc.c
===================================================================
--- gcc/tree-ssa-reassoc.c (revision 186393)
+++ gcc/tree-ssa-reassoc.c (working copy)
@@ -544,6 +544,28 @@ add_repeat_to_ops_vec (VEC(operand_entry_t, heap)
reassociate_stats.pows_encountered++;
}
+/* Add an operand entry to *OPS for the tree operand OP, giving the
+ new entry a larger rank than any other operand already in *OPS. */
+
+static void
+add_to_ops_vec_max_rank (VEC(operand_entry_t, heap) **ops, tree op)
+{
+ operand_entry_t oe = (operand_entry_t) pool_alloc (operand_entry_pool);
+ operand_entry_t oe1;
+ unsigned i;
+ unsigned max_rank = 0;
+
+ FOR_EACH_VEC_ELT (operand_entry_t, *ops, i, oe1)
+ if (oe1->rank > max_rank)
+ max_rank = oe1->rank;
+
+ oe->op = op;
+ oe->rank = max_rank + 1;
+ oe->id = next_operand_entry_id++;
+ oe->count = 1;
+ VEC_safe_push (operand_entry_t, heap, *ops, oe);
+}
+
/* Return true if STMT is reassociable operation containing a binary
operation with tree code CODE, and is inside LOOP. */
@@ -1200,6 +1222,7 @@ undistribute_ops_list (enum tree_code opcode,
dcode = gimple_assign_rhs_code (oe1def);
if ((dcode != MULT_EXPR
&& dcode != RDIV_EXPR)
+ || oe1->count != 1
|| !is_reassociable_op (oe1def, dcode, loop))
continue;
@@ -1243,6 +1266,8 @@ undistribute_ops_list (enum tree_code opcode,
oecount c;
void **slot;
size_t idx;
+ if (oe1->count != 1)
+ continue;
c.oecode = oecode;
c.cnt = 1;
c.id = next_oecount_id++;
@@ -1311,7 +1336,7 @@ undistribute_ops_list (enum tree_code opcode,
FOR_EACH_VEC_ELT (operand_entry_t, subops[i], j, oe1)
{
- if (oe1->op == c->op)
+ if (oe1->op == c->op && oe1->count == 1)
{
SET_BIT (candidates2, i);
++nr_candidates2;
@@ -3275,8 +3300,10 @@ attempt_builtin_powi (gimple stmt, VEC(operand_ent
gsi_insert_before (&gsi, pow_stmt, GSI_SAME_STMT);
}
- /* Append the result of this iteration to the ops vector. */
- add_to_ops_vec (ops, iter_result);
+ /* Append the result of this iteration to the ops vector.
+ Give it a rank higher than all other ranks in the ops vector
+ so that all uses of it will be forced to come after it. */
+ add_to_ops_vec_max_rank (ops, iter_result);
/* Decrement the occurrence count of each element in the product
by the count found above, and remove this many copies of each
