[Bug middle-end/28690] [4.2 Regression] Performace problem with indexed load/stores on powerpc

[dberlin at dberlin dot org]

------- 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