On Mon, 2013-09-09 at 14:25 +0800, bin.cheng wrote:
> Thanks for reviewing, I will correct all stupid spelling problem in the next
> version of patch.
>
> On Mon, Sep 9, 2013 at 8:15 AM, Bill Schmidt <wschm...@linux.vnet.ibm.com>
> wrote:
> >
> >>>+ int (i * S).
> >>>+ Otherwise, just return double int zero. */
> >
> > This is sufficient, since you are properly checking the next_interp
> > chain. Another possible form would be
> >
> > X = (B + i) * 1,
> >
> > but if this is present, then one of the forms you're checking for should
> > also be present, so there's no need to check the MULT_CANDs.
> I'm not very sure here since I didn't check MULT_CAND in the patch. Could
> you please explain more about this?
Sorry, perhaps I shouldn't have mentioned it. I was simply stating
that, although a candidate representing B + i could be represented with
a CAND_MULT as shown, there is no need for you to check it (as you
don't) since there will also be a corresponding CAND_ADD in one of the
other forms. Since you are walking the next_interp chain, this works.
In other words, the code is fine as is. I was just thinking out loud
about other candidate types.
>
> >
> >>>+
> >>>+static double_int
> >>>+backtrace_base_for_ref (tree *pbase)
> >>>+{
> >>>+ tree base_in = *pbase;
> >>>+ slsr_cand_t base_cand;
> >>>+
> >>>+ STRIP_NOPS (base_in);
> >>>+ if (TREE_CODE (base_in) != SSA_NAME)
> >>>+ return tree_to_double_int (integer_zero_node);
> >>>+
> >>>+ base_cand = base_cand_from_table (base_in);
> >>>+
> >>>+ while (base_cand && base_cand->kind != CAND_PHI)
> >>>+ {
> >>>+ if (base_cand->kind == CAND_ADD
> >>>+ && base_cand->index.is_one ()
> >>>+ && TREE_CODE (base_cand->stride) == INTEGER_CST)
> >>>+ {
> >>>+ /* X = B + (1 * S), S is integer constant. */
> >>>+ *pbase = base_cand->base_expr;
> >>>+ return tree_to_double_int (base_cand->stride);
> >>>+ }
> >>>+ else if (base_cand->kind == CAND_ADD
> >>>+ && TREE_CODE (base_cand->stride) == INTEGER_CST
> >>>+ && integer_onep (base_cand->stride))
> >>>+ {
> >>>+ /* X = B + (i * S), S is integer one. */
> >>>+ *pbase = base_cand->base_expr;
> >>>+ return base_cand->index;
> >>>+ }
> >>>+
> >>>+ if (base_cand->next_interp)
> >>>+ base_cand = lookup_cand (base_cand->next_interp);
> >>>+ else
> >>>+ base_cand = NULL;
> >>>+ }
> >>>+
> >>>+ return tree_to_double_int (integer_zero_node);
> >>>+}
> >>>+
> >>> /* Look for the following pattern:
> >>>
> >>> *PBASE: MEM_REF (T1, C1)
> >>>@@ -767,8 +818,15 @@ slsr_process_phi (gimple phi, bool speed)
> >>>
> >>> *PBASE: T1
> >>> *POFFSET: MULT_EXPR (T2, C3)
> >>>- *PINDEX: C1 + (C2 * C3) + C4 */
> >>>+ *PINDEX: C1 + (C2 * C3) + C4
> >>>
> >>>+ When T2 is recorded by an CAND_ADD in the form of (T2' + C5), It
> > ^ ^
> > a it
> >
> >>>+ will be further restructured to:
> >>>+
> >>>+ *PBASE: T1
> >>>+ *POFFSET: MULT_EXPR (T2', C3)
> >>>+ *PINDEX: C1 + (C2 * C3) + C4 + (C5 * C3) */
> >>>+
> >>> static bool
> >>> restructure_reference (tree *pbase, tree *poffset, double_int
> > *pindex,
> >>> tree *ptype)
> >>>@@ -777,7 +835,7 @@ restructure_reference (tree *pbase, tree *poffset,
> >>> double_int index = *pindex;
> >>> double_int bpu = double_int::from_uhwi (BITS_PER_UNIT);
> >>> tree mult_op0, mult_op1, t1, t2, type;
> >>>- double_int c1, c2, c3, c4;
> >>>+ double_int c1, c2, c3, c4, c5;
> >>>
> >>> if (!base
> >>> || !offset
> >>>@@ -823,11 +881,12 @@ restructure_reference (tree *pbase, tree
> > *poffset,
> >>> }
> >>>
> >>> c4 = index.udiv (bpu, FLOOR_DIV_EXPR);
> >>>+ c5 = backtrace_base_for_ref (&t2);
> >>>
> >>> *pbase = t1;
> >>>- *poffset = fold_build2 (MULT_EXPR, sizetype, t2,
> >>>- double_int_to_tree (sizetype, c3));
> >>>- *pindex = c1 + c2 * c3 + c4;
> >>>+ *poffset = size_binop (MULT_EXPR, fold_convert (sizetype, t2),
> >>>+ double_int_to_tree (sizetype, c3));
> >
> > I am not sure why you changed this call. fold_build2 is a more
> > efficient call than size_binop. size_binop makes several checks that
> > will fail in this case, and then calls fold_build2_loc, right? Not a
> > big deal but seems like changing it back would be better. Perhaps I'm
> > missing something (as usual ;).
> I rely on size_binop to convert T2 into sizetype, because T2' may be in other
> kind of type. Otherwise there will be ssa_verify error later.
OK, I see now. I had thought this was handled by fold_build2, but
apparently not. I guess all T2's formerly handled were already sizetype
as expected. Thanks for the explanation!
Bill
>
> Thanks.
> bin
>
>
>
>
