------- Comment #2 from dberlin at gcc dot gnu dot org 2006-08-11 14:33 -------
Subject: Re: [4.2 Regression] Performace problem with
indexed load/stores on powerpc
Here is the reassoc patch that puts them in the right order at the tree
level.
Index: tree-ssa-reassoc.c
===================================================================
--- tree-ssa-reassoc.c (revision 115962)
+++ tree-ssa-reassoc.c (working copy)
@@ -356,6 +356,13 @@ sort_by_operand_rank (const void *pa, co
&& TREE_CODE (oeb->op) == SSA_NAME)
return SSA_NAME_VERSION (oeb->op) - SSA_NAME_VERSION (oea->op);
+ /* For pointers, most things want the *base* pointer to go first to
+ try indexed loads. The base pointer is the one with the *lesser*
+ rank. For everything else, put them in order from greatest rank
+ to least. */
+ if (POINTER_TYPE_P (TREE_TYPE (oea->op)))
+ return oea->rank - oeb->rank;
+
return oeb->rank - oea->rank;
}
@@ -1309,7 +1316,9 @@ reassociate_bb (basic_block bb)
if (TREE_CODE (stmt) == MODIFY_EXPR)
{
tree lhs = TREE_OPERAND (stmt, 0);
+ tree lhst = TREE_TYPE (lhs);
tree rhs = TREE_OPERAND (stmt, 1);
+ tree rhst = TREE_TYPE (rhs);
/* If this was part of an already processed tree, we don't
need to touch it again. */
@@ -1318,10 +1327,10 @@ reassociate_bb (basic_block bb)
/* If unsafe math optimizations we can do reassociation for
non-integral types. */
- if ((!INTEGRAL_TYPE_P (TREE_TYPE (lhs))
- || !INTEGRAL_TYPE_P (TREE_TYPE (rhs)))
- && (!SCALAR_FLOAT_TYPE_P (TREE_TYPE (rhs))
- || !SCALAR_FLOAT_TYPE_P (TREE_TYPE(lhs))
+ if (((!INTEGRAL_TYPE_P (lhst) & !POINTER_TYPE_P (lhst))
+ || (!INTEGRAL_TYPE_P (rhst) && !POINTER_TYPE_P (rhst)))
+ && (!SCALAR_FLOAT_TYPE_P (rhst)
+ || !SCALAR_FLOAT_TYPE_P (lhst)
|| !flag_unsafe_math_optimizations))
continue;
--
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=28690
